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					         Center for
Nano- Science and Technology


             of


University System of Taiwan
                       TABLE OF CONTENTS

                                                                              Page
中文摘要                                                                             2
1.    Abstract                                                                   3
2.    Objectives and Background Information                                      3
3.   Infrastructure and Organization                                             7
4    Project Description                                                        10
     4.1 Center of Excellence                                                   10
     4.2 Research Programs                                                      11
         4.2.1 Nano-electronics and quantum computation                         11
               4.2.1.1 Nano CMOS                                                11
                4.2.1.2 Exploratory devices                                     14
                4.2.1.3 Quantum computation                                     18
         4.2.2 Nano-photonics                                                   19
               4.2.2.1 Nanodevice and fabrication                               20
                4.2.2.2 Nanostructure fabrication and patterning                24
                4.2.2.3 Nanostructure characterization                          28
         4.2.3 Nano-bioelectronics and bio-nanotechnology                       30
                4.2.3.1 Researches on the key technologies of nano-
                         bioelectronic devices                                  31
                4.2.3.2 Manipulation and detection of single biomolecules       34
                4.2.3.3 Cell/tissue engineering utilizing nanotechnology        37
     4.3 International cooperation                                              40
     4.4 Industrial collaboration                                                41
     4.5 Education                                                               42
5.   Expected Results and Achievement                                            43
     5.1 Cost-effective research at the frontiers of nano science and technology 43
     5.2 Education and training support in nano science and technology           44
     5.3 Impact on nano industry                                                 44
6.   Core facility                                                               45
7.   Budget and Personnel                                                        46
8.   Self-Assessment of the Participating Universities                           47
     8.1 National Central University         (NCU)                               47
   8.2 National Chiao Tung University (NCTU)                                    48
   8.3 National Tsing Hua University (NTHU)                                     48
   8.4 National Yang Ming University (NYMU)                                     49
9. Assessment of the Center for Nano-Science and Technology                     49
                                         1
中文摘要


  奈米科技是二十一世紀科技發展之重要領域,本計畫係經中央、交大、清華
和陽明四校教授多次討論,通力合作之結晶,計畫書充分顯示奈米研究之跨領域
性及四校共同成立奈米中心之重要性。整個計畫涵蓋奈米科技研究、教學及業界
合作三部份,四校將集中人力及物力共同追求在奈米科技研究之卓越,四校通力
合作,將此領域研究提昇至國際一流水準。


   四校奈米研究中心將建立中心實驗室及區域實驗室,所規劃的重點包括:奈
米材料、奈米科學、奈米元件及奈米生技。這些重點將針對下面四項目標進行研
 (1)奈米電子元件及量子計算技術,
究:                         (3)單一生醫分子
                  (2)奈米光電元件,
與細胞組織之操控與行為研究及(4)奈米生物電子元件之研發與應用。


  計畫書中亦涵蓋中心之組織架構、中心運作、研究計畫管理及中心之評估機
制。在引進人才方面,中心已爭取到瑞典 Lunds University 趙光安教授(專長為
奈米元件與 Spintronic 理論)同意擔任諮詢委員且回國參與研究,亦邀請張立綱
院士、朱隸文院士、何志明院士及 Prof. Dr. Manfred Pilkuhn 等擔任諮詢委員,此
外,四校也將積極爭取一些在國外做奈米研究之年輕學者加入本中心研究行列。




                         2
1.   Abstract

       This proposal for the establishment of a Center for Nano-Science and
Technology (CNST) is the outgrowth of numerous meetings ─ both intra- and
inter-university ─ involving many faculty members with diverse science and
technology backgrounds from the four campuses (NCU, NCTU, NTHU, NYMU) of
the University System of Taiwan (UST). This unprecedented feat of collaboration
(for Taiwan) both demonstrates the cross-disciplinary nature of nano-research and
conveys the sense of priority placed on this field by our university system. During
the course of the preparation of this proposal, we have glimpsed in microcosm the
benefits that can be derived when four universities work earnestly together toward a
common goal. Divided, we have done well in the past; united, we expect greater
excellence in the years to come. The challenges are daunting, but we do not intend to
fail in the test.



2.   Objectives and Background Information

     At the beginning of the twenty-first century, nanotechnology has taken the world
by storm. One hundred years after the discovery of quantum physics, which
revolutionized our view of the microworld, we are beginning to realize the dream of
the eminent physicist Richard Feynman who foresaw a future in which the most
powerful machines of the future would not be very large, but extremely small. The
resulting technology that may be possible by building devices and materials starting
from atomic and molecular levels will have a profound impact on the daily life of
every inhabitant of this planet.
     As a simple example, consider the following computer application. At its base,
machine computation relies on active elements that are either in an ON state or in an
OFF state to represent the 1 and 0 of binary arithmetic. A semiconductor is an
appropriate material for such logic or storage devices because small controlling
voltages can be applied to make currents flow (YES = ON = 1) or not flow (NO =
OFF = 0). But at the nanoscale, the distinction among insulator, semiconductor, and
conductor begins to blur because of tunneling effects associated with quantum
mechanics.      Thus, nanotechnology offers unprecedented opportunities and
challenges for the computer industry in its drive to pack active elements into a given
space more densely to make ever more powerful machines. This proposal contains
much more sophisticated examples than the above, but the principle should be clear.
     Although quantum mechanics has become the underlying theory of all the


                                          3
natural sciences, applications of the discipline to the manufacture of ordinary goods
has lagged. Except for specialized scientific experiments, the precision needed for
machinery and production tools seldom reached a nanometer, the size of a typical
molecule. But the requirements of technology are changing quickly. In the IC
industry, for example, the capacity and speed of large memory chips and fast CPUs
double every few years because of the shrinkage of the critical dimensions of
transistors, the basic building blocks of integrated circuits. Transistors with 130nm
channel length are already in production; very soon 90nm transistors will become
available. In this industry we are already at the dawn of the era of nanotechnology.
     Recent advances in Scanning Probe Microscopy (SPM) make it possible to
manipulate atoms one by one. Quantum dots, quantum wires, and quantum wells have
all been produced in laboratories. New components and new materials appear
continually, and they will lead to devices undreamt of just a few short years ago. The
breakthroughs possible with nanotechnology may well match in ultimate impact the
changes wrought for the benefit of mankind by the industrial revolution during the
18th century.
      No society with ambitions in the high-tech sector can afford to ignore the
economic consequences of the coming nanotechnology revolution. According to Dr.
M. C. Roco, Director of America’s National Nanotechnology Initiative (NNI), the
total market size for nanotechnology products and services, as projected by various
US industry associations, will add up to US$ 1 trillion in ten to fifteen years. Because
of this prospect, worldwide R&D investment in nano science and technology has
escalated rapidly in the past few years. For the year 2002 alone, the American
government’s budget for nanotechnology was more than US$500 million. Private
sector investment has been correspondingly impressive. Similar growth has occurred
in Japan, Canada, and Europe. In Taiwan, the National Science Council (NSC) and the
Industrial Technology Research Institute (ITRI) has formulated a national initiative on
nano science and technology. The total budget for the next five years will probably be
more than 1 billion US dollars. The R&D effort will cover all fields affected by and
affecting nanotechnology. Besides the semiconductor and electronics industry, these
areas include material science, chemical engineering, biology, medicine,
environmental engineering, and the physical and mathematical sciences.
     Because scientists and engineers in the nano field straddle the macroscopic and
microscopic worlds, where the traditional bulk properties of materials blend with the
quantum behavior of individual atoms and molecules, they are on relatively
unfamiliar ground. The applications are therefore not readily separated from the
basic research. University research groups will play a critical role in shaping the
future of the technology. Moreover, universities will be the principal supplier of the


                                           4
manpower needed by industry. In the past, the success of the IC and IT companies
located in the Hsinchu Science-based Industrial Park (HSIP) greatly influenced the
engineering curriculum at the major research universities of Taiwan. Nano science,
with its broader front of possible applications and its greater cross-disciplinary nature
will have an even greater influence. Indeed, no single department, and perhaps no
single university in Taiwan, can hope to construct anything approaching a
comprehensive research and education program in the nano sciences. We believe
that a Center with the combined resources – human capital and fiscal capital -- of the
four-university system consisting of NCTU, NTHU, NCU and NYMU provides a
viable organization to meet the challenges posed by the nano revolution.
      At present, each of the four universities in UST has its own nano program.
With the support of the MOE, we propose to perform a system-wide integration of our
diverse efforts in both research and education. New exciting directions could
emerge from the resulting synergy. For example, we are organizing an effort in
nano-biotechnology by bringing together NYMU, known for its expertise in
biomedical research, to work together with NCTU, known for its expertise in
microelectronics, NTHU, known for its expertise in materials science, and NCU,
known for its expertise in optics. The formation of the UST consortium is designed to
promote this type of large-scale cross-disciplinary program.
      The Center proposed here will play an integral part in the National Nano
Initiative. It will carry out research programs overseen by the NSC, and it will work
closely with ITRI to support their development efforts in nano technology. ITRI has
already signed R & D agreements with members of the four-university system. NCTU
and NTHU have formulated and started a program to train ITRI employees on various
topics in nano science and technology. A training program for HSIP employees on
nano technology is in the planning stages. The proximity of ITRI and HSIP to the
campuses of UST will make collaboration feasible, resulting in a shorter lag time
between basic research results and products ready for the marketplace.
    We hope to involve the Institute of Applied Science and Engineering Research
(IASER) of Academia Sinica once it is formed. The Center will also work closely
with national research institutions such as the National Nano Device Laboratory
(NDL), Synchrotron Radiation Research Center (SRRC), National Center for
High-Performance Computing (NCHC), National Center for Theoretical Sciences
(NCTS), and Precision Instrument Development Center (PIDC). Except for
Academia Sinica, all of these institutions are located in Hsinchu and have long
histories of cooperation with members of the UST. The relationship between the
UST nano science consortium and other institutes and organizations is illustrated
schematically by the following diagram.


                                           5
                                   NSC and MOE



                                      PIDC
             CTS
                                                             NCHC


     NDL
                                     CNST                              SRRC



 IASER
                            ITRI                  World communities in nano
                                                  science and technology

         Science Park



       It should be emphasized that all these national labs and organizations are within
10 kilometers from one another and from the NCTU and NTHU campuses of the UST
consortium. This makes possible close interaction and mutual stimulation. When
one adds the complementary scientific interests and expertise of the NCU and NYMU
faculties and staff, the commercialization experience of ITRI, the vertical integration
possible with HSIP, and the international reputation and presence of Academia Sinica,
one has a truly formidable force in the nano research arena. The combined manpower
involved in nano research alone will number more than 1000. The key to success
will be concentration of the diverse groups into a coherent team. The start made by
the integration of the individual thrusts of NCU, NCTU, NTHU, and NYMU into a
system-wide effort makes us optimistic about such collaboration.

    The objectives of the UST in establishing the Center for Nano Science and
Technology (CNST) are therefore simple and clear:

1. to create a center of research excellence to lead Taiwan aggressively into the
   burgeoning field of nano science and technology;
2. to provide a center of educational excellence for the advanced teaching and
   training of personnel in the field of nano science and technology;


                                           6
3. to act as a center of nucleation to help Taiwan become one of the frontrunners in
   the commercialization of nano technology.




3. Infrastructure and Organization

    The Center for Nano Science and Technology has three major functions:
Research, Education, and Service. Research in nano science requires talents and tools
from many diverse disciplines. A good program-management mechanism and a
central facility need to be established to coordinate the various activities to promote a
hierarchy of desirable and necessary interactions. Four different research branches
are listed in the organization chart. They are Nano Sciences, Nano Materials, Nano
Devices and Applications, and Nano Biotechnology. There will be separate program
management teams and laboratories to handle projects in these four areas. A central
facility that houses expensive equipment and software tools common to many
research directions will be established to serve the needs of the entire Taiwan nano
community. This central facility will consist of a central processing lab for nano
fabrication, an analysis lab for structural analysis, and a computer center with
high-speed connections to the NCHC.

      Education is a unique and important responsibility for our Nano Center. By
combining the teaching resources from four top universities with the experience and
star power of Academia Sinica, ITRI, and HSIP, we can provide a breadth of training
in nano science and technology that competes with the best efforts in the world.
Together, we have the personnel (over 150 faculty members actively involved in
research in this field) and the motivation to put forward a comprehensive curriculum
in nano science and technology. Students from research universities throughout
Taiwan and staff from Taiwan’s high-tech industries will be eligible to take courses
from any campus of the UST. Many of these courses will be offered on-line. Graduate
students in UST will be able to select research subjects jointly supervised by
professors in different disciplines from any combination of the four campuses.
Flexibility and opportunity will be the hallmarks of our teaching program.

      International collaboration with overseas universities, companies, and research
institutes will be another important feature of our Nano Center. The Center will
work closely with the Offices of International Relations on the campuses of the UST
to promote programs of exchange involving students, visiting scholars, and industrial
collaborators. Apart from formal courses, we will hold regular seminars and
workshops to bring together top-notch researches and policy makers from all over the
                                           7
world for discussion and debate. Global reach and interaction will be the hallmarks
of our interface with the rest of the world.

      The organization of the CNST is shown in the following Figure. There will be
four departments supervised and helped by a Center Director and central
administrative staff. The four departments have charge of education, the common
facility, the four research programs, and research collaborations within Taiwan and
overseas. The Center Director reports to a steering committee, consisting of the Deans
of Research and Development from the four campuses of the UST, who will provide
policy guidance for the operation of the Center and an interface with research efforts
in other fields within and outside the system. An advisory committee consisting of
representatives appointed by the Presidents of Academia Sinica and ITRI, a prominent
expert from HSIP, and suitable scientists, industrialists, and policy makers of world
renown will provide external input on promising research directions as well as
periodic reviews of the performance of the Center.




                                          8
                                                                  Center for Nano Science and Technology

                Steering committee
                                                                                                                             Advisory committee
         (representatives from four schools)


                                                                               Center director




Education                              Common facility                      Research programs                Research collaborations                       Administration




    Nano curriculum              Lab management and safety                  Program management                                                                 finance
                                                                                                                           International

                                                                                                                           collaboration

                                                                                           Nano Science                                                        Human resources
                                               Common processing lab.
    Nano seminars


                                                                                        Nano Materials                     ITRI                                Industrial relations

                                               Computing center                                                            collaboration

    Training courses
                                                                                           Nano Devices                                                        Legal depart.


                                               Common analysis lab
                                                                                                                           Collaboration with other
    Conferences and                                                                     Nano biotechnology
                                                                                                                           universities and institutions
    workshops



                                                                                       9
4. Project Description

4.1 Center of Excellence

     Through a highly successful electronics and semiconductor industry promoted
by enlightened industrial policies that were the envy of the world, Taiwan derived
tremendous economic benefits and technological prestige. As we move from the
computer age to the nano age, the question arises whether Taiwan can maintain its
technological edge. The driving force for the computer age is semiconductor
technology, which has a well-understood scientific base. The nano age involves
much less well-studied areas of knowledge and a much broader base of needed
technology development and manufacturing processes. Many of the batch
processing techniques from the semiconductor industry are useful, perhaps even
indispensable, for the new efforts in nanotechnology and its closely related cousin,
MEMS (microelectromechanical systems). As a proven leader in providing
mistake-free electronic and optical components at the lowest cost, Taiwan may be in
a good position to compete internationally in the ultimate manufacture of nano
devices and systems. However, the transition may be rough if Taiwan does not
participate in the high-end processes of human resource training, knowledge
creation, technology innovation, and end-product development and marketing.
Because of its multi-disciplinary character, capital investment requirements, and
far-reaching industrial applications, we need enlightened governmental policies in
the promotion of academic-industrial cooperation in this highly competitive area.
The CNST of UST can play a critical role in the necessary vertical and horizontal
integrations of human and material resources.

     Nano science and technology is one of the great intellectual voyages of
exploration of our time. The most important ingredient in any intellectual endeavor
of this type is human talent. Especially needed are talents in materials science,
chemical engineering, mechanical engineering, biology and biomedicine, and the
physical and mathematical sciences. The top talents in these fields to be found in
Taiwan today reside at the research universities and Academia Sinica. Because of
our history, tradition, and location, the UST is in the best position among all Taiwan
research universities to recruit outstanding people from abroad who are the
internationally recognized experts in the field. We are also in the best position to
provide the sound training program in the basic quantum physics and chemistry
needed by students to deal with the microscopic world of nanostructures. By
combining forces with Academia Sinica, ITRI, and HSIP, we will become a center
of academic and industrial excellence to power the nano revolution in Taiwan.

                                          10
4.2 Research programs

    The description for the research program is divided into three major parts:
    4.2.1 Nano-Electronics and Quantum Computation,
    4.2.2 Nano-photonics,
    4.2.3 Nano-Bioelectronics and Bio-Nanotechnology.


4.2.1 Nano-Electronics and Quantum Computation

       More than two decades ago, Gordon Moore of Intel formulated his famous
“law” that the number of transistors incorporated into a memory chip increases by a
factor of two every eighteen months. Roughly half of this increase comes from a
reduction of the feature sizes on the chips; the other half, from factors like design
improvements or increases in chip die sizes. This trend has governed the strategy of
silicon IC technologies in the past. Any extrapolation of this curve into the future
relies on questionable assumptions that technological advances can evolve to meet
continued reductions of the feature size and that the economics of silicon IC demand
will continue to justify further integration efforts.
     Everyone agrees that the required long-term technological advances can come
only by developing nanotechnology. The Semiconductor Industry Association
(SIA) roadmap projects feature sizes of 70 nanometers by 2010. Further reductions
demand new materials, novel process techniques [such as atomic-layer chemical
vapor deposition (ALCVD) for ultra-thin film deposition with atomic layer
accuracy], and the scaling/simulation of devices at higher levels of integration.
The path to feature sizes smaller than 0.07 micron might also be achievable by
bottom-up self-assembly approaches. These approaches require exploration of
phenomena at the quantum scale and the invention of new tools for molecular-scale
synthesis and manipulation.
     The program in this category will consist of R & D in three major areas: Nano
CMOS, Exploratory Devices, and Quantum Computation.


4.2.1.1 Nano CMOS

   The leading IC company TSMC has announced 90 nanometers fabrication by
2003. Presumably, technologies for 65 nm are under consideration. It is therefore
desirable for our program to deal with the technology development of 45 nanometers
and smaller, without which the most advanced and essential industry in Taiwan
would have difficulty. The 45 nm complementary metal-oxide-semiconductor
(CMOS) technologies will include the build-up of an extremely thin high-k

                                          11
dielectrics on top of a Si strained layer structure ( SiGe / Si strained / SiGe graded) ,
followed by a novel gate structure and nano-scale interconnects. We will cooperate
with the engineers of TSMC and the Electronic Research and Service Organization
(ERSO) of ITRI on this research. Special emphasis will be placed on the
investigation of the various interfaces encountered in the nano CMOS structure.


High-k Dielectrics
     Reductions in the current sizes of CMOS devices require the gate oxide to be
reduced in “equivalent” thickness to less than 1 nm.     However, the leakage current
becomes unacceptably high because of direct electron tunneling across dielectrics of
this thickness.   To achieve equivalent oxide thicknesses (EOT) of gate dielectrics
           
below 10 A , workers have studied higher-k materials such as Ta2O5, Al2O3, ZrO2,
HfO2, etc. Although progress has been achieved, the ensuing thermal processing
cycles cause the diffusion of metal and oxygen and degrade the electrical properties
of MOSFET. Therefore, the quality of gate dielectric or gate dielectric/Si interfaces
is one of the key issues for developing nano-scale MOSFET.
     An idea to be pursued in this proposal includes surface nitridation by
mono-layer silicon nitride gas as a buffer layer in the formation of high-k metal
                              
oxide with EOT below 10 A .        We have already made thin Si3N4 films by this
process.   We will next try to find the optimal composition ratios, time for oxidation,
and thickness for forming effective high-k metal oxide films.         The high-k metal
oxide is deposited by an Atomic Layer Deposition (ALD) system, which we will set
up as part of the research program, on the interfacial buffer layer of Si3N4 (or
alternatively, SiNO).     Preliminary research may occur with e-gun or sputter
techniques in the absence of ALD. The deposition will be followed by an
appropriate annealing process, whose temperature parameters we will attempt to
define and control. We will investigate the effect of proper silicon doping to reduce
diffusion during post-deposition annealing. Poly-Si or TiN films will be used as
the gate electrodes to minimize reaction with the gate dielectrics.      The goal is to
achieve a gate dielectric of EOT as thin as possible, compatible with the electrical
properties of the MOS device.
    The challenging part of this project is to optimize the process for making a
                                     
buffer layer with a thickness of 3-5 A or less. This film has to approach a mono-layer,
if we are to achieve the desired effective oxide thickness.      With an ALD system,

                                            12
the task can be satisfactorily completed. University Professor G. Lucosky of North
Carolina University has agreed to participate and help guide this research activity.
His experience and expertise will be tremendously helpful in our study.


Novel Gate Structure or Materials
     Double-gate structure is one of the best alternatives in limiting the short-channel
effects in scaled devices because of the excellent gate control of the channel
potential. To reduce the effect of dopant statistics, the channel region should be
undoped. Consequently, threshold voltage control is best realized by adjusting the
workfunction of the gate electrode. This means changing materials to either SiGe or
metals. We are equipped with an ion implanter using various solid sources, which
could greatly facilitate the metal gate fabrication.
      Current implementations of double-gate structure and metal electrode are
somewhat incompatible. Hence, we propose to look at novel ways of integrating
metal gate electrodes with a double-gate structure.


  Nano-scale Interconnect
    Reductions in IC feature sizes and the continuing trend toward larger chips with
higher levels of integration lead to an increase in the RC delay associated with the
on-chip interconnect. The interconnect RC delay exceeds the gate delay and tends
to dominate the overall performance of the circuit when the feature size becomes
less than 0.25 micron. The performance degradation is due to higher resistance of
the metal leads and higher capacitance between the more tightly spaced
interconnects. Therefore, future developments will replace aluminum alloy
interconnects with copper, and incorporate low-k inter-layer dielectrics (ILD).
Although the 0.18 micron generation of devices already implement copper
metallization using chemical mechanical polish (CMP) and dual damascene
techniques, further reductions of feature size to beyond 65 nm will encounter new
challenges. One is the inapplicability of current electroplating techniques without
ultra-thin diffusion barriers and adequate step-coverage. We have developed a
Photo-assisted Chemical Vapor Deposition technique and used it successfully to
deposit 40 nm copper film under temperature as low as 125 ℃ with good stress
lifetime and gap fill ability. Further development on photo-assisted ALCVD is
proposed to achieve better control of the barrier/copper layer deposition process.
For planarization, we will research a CMP-less technology integrating Cu
electropolishing and single-step CMP with high removal selectivity between Cu and
barrier metals.
    The second part of this project is aimed at developing a low-k ILD suitable for

                                           13
45 ~ 65 nm devices.            An ECR-CVD technique has been used to deposit
amorphous carbon nitride (a-CN)with good thermal stability, adhesion and k value
< 2.0. Future development will include continued efforts on a-C:N, or new
materials like a-C:N:F, etc.


4.2.1.2 Exploratory Devices


CNT-based Nano-electronics
  Carbon Nanotube (CNT) is a new form of carbon material resulting from
research on C60. In addition to its unusual mechanical properties, CNTs can be
metallic or semiconductive. Several investigators at IBM have reported that CNTs
can be used as a field effect transistor in nano-electronics (R. Martel, T. Schmidt, H.
R. Shea, T. Hertel, P. Avouris, Appl. Phys. Lett. 1998, 73, 2447-2449). CNTs were
found to be always p-type, i.e., the current carriers are holes, and the circuits are ON
only when a negative bias gate voltage is applied. Later, the same group developed
a post-growth method to convert CNTs to n-type field effect transistors (V. Derycke,
R. Martel, J. Appenzeller, P. Avouris, Nano Lett. 2001, 453-456). The post-growth
doping method for converting p-type to n-type CNTs, however, is tedious in practice.
It is desirable to develop intrinsic n-type CNTs field effect transistors by other
methods, such as by doping the CNTs during growth. Other research groups have
demonstrated the importance of in-situ doping of heteroatoms and encapsulation of
metals during the growth process of CNTs.
    CNTs can be prepared by many different processes, such as, plasma discharge of
graphite electrodes in an inert atmosphere, chemical vapor decomposition of
hydrocarbons by metal catalysts, laser ablation of graphites in a high temperature
oven, hydrothermal chemical reactions, etc. The electronic properties of CNTs are
strongly dependent on chirality, defects, diameters, number of layers, etc. The
relative influence of these factors is not understood. It is necessary to control the
processes of growth to have a good handle on these factors, and thus on the
electronic properties of CNTs. The first part of this project is to achieve the
controlled preparation of various kinds of carbon nanotubes, doped by heteroatoms
(such as, N, P, B, etc.) or by having various metals (such as, Fe, Co, Ni, etc.) or
composite materials encapsulated inside the internal hollow space.
    The second part of the project includes the study of electronic transport at the
nano-scale and the development of ambient temperature single-electron transistors
(SETs) based on CNTs. CNTs are important because their sizes are ideal for many
applications in nanodevices. But before this dream can be realized, we must first
understand the low-dimensional mechanism of electrical conductivity in CNTs,


                                           14
which is a hot subject of current research. Defects in the CNT or a bending of the
tube may turn it into a SET device. Hence, studying the conduction mechanism and
the device applications of CNT is a good starting point for developing this kind of
nano-technology.
    In the literature, we find three ways to make electrical contacts to CNT. The first
method is to lay down many gold electrodes on an insulating substrate, and then
drop a little CNT suspending solvent in the area of the electrodes. One then has to
find a CNT laying across two or more electrodes for further measurements. In
many cases, with the tip of a scanning probe microscope (SPM), one has to get rid of
the excess amorphous carbon which is inevitably associated with CNT’s. A second
method is to deposit CNT on an area where electrodes separated by micrometers are
previously deposited. One then has to find a useable CNT to which one attaches gold
electrodes by e-beam lithography. A lift-off of the device completes the process. A
third method is to grow CNT’s on preset catalytic micro-pads, and then to deposit
gold electrodes on those catalytic pads with an appropriately connected CNT.
   We prefer the third method (or its possible improvements) because the locally
grown CNTs have not gone through chemical or physical purification processes that
may introduce defects in the CNTs. Once we have perfected the growth and
assembly processes, we will be able to make detailed studies of the mechanism of
electrical conduction in CNTs. We will begin by answering simple questions such as
whether certain types of CNT are semiconductive or metallic and how their
electronic properties depend on the preparation process. We will next explore the
possibility of turning CNTs into active devices by introducing artificial defects in the
tube. We will begin with SET devices.


      The working principle of SET devices, which has been studied for many years,
is based on the tunneling conduction of current carriers through a nanometer-sized
quantum dot, which can be gated with another electrode not involved in the electric
conduction. We view the fabrication of SET devices as a demonstration of the
nano-device capability of CNTs. After we can make SET devices with a
reasonable yield rate, we will apply them to devices in metrology. In the present
metrological community, SET devices are made by e-beam lithography with double
layers of PMMA resist and the multiple-angle evaporation of aluminum, taking
advantage of the fact that aluminum can be oxidized to make good junctions in a
reproducible manner. However, metrological SET devices currently operate only at
extremely low temperatures, and thus are restricted in their possible applications.
We will examine two methods for fabricating the high temperature SET devices.
    One method is to fabricate a thin wire of highly doped Si on a SOI (silicon on


                                           15
insulator) substrate. The irregular structures in the 20 nm wide Si wire serve as
quantum dots required for SET. Once gated by imposed voltage on an extra
electrode, the current flowing through the Si wire can exhibit the characteristic
oscillations of SET even at room temperature. Another method is to use SPM to
carve an isolated quantum dot in a thin (< 100A ) metal film between two electrodes,
with nano-oxidation. Oscillatory I-V curves of these devices at room temperature
have been observed by several groups. Our physics group possesses the expertise in
the two nano-lithographic techniques needed for fabricating room temperature SET
devices.


Silicon-based Quantum Dots Superlattice Structure Devices
    Luminescent material based on silicon has attracted great attention in recent
years because it can combine the state-of-the–art silicon integrated circuits with
optoelectronic applications. Our approach to self-assembled silicon quantum dots
growth exploits recent developments in plasma-assisted chemical-vapor deposition
of silicon-rich nitride and oxynitride thin films. Devices with intense and
sequentially adjustable light emission ranging from infrared to blue can be
fabricated via the simple process by varying the nano-dot sizes ( 1-5 nm). The
photoluminescence yield of these films is comparable to bulk GaAs samples at room
temperature. Our group found the first case of white light electroluminescence (EL)
from a silicon nitride film structure (H.L. Hwang et al., Applied Physics Letters
2002).
    The strong photoluminescence is believed to originate with an interface of
trapped states stabilized by the quantum confinement effect. Unfortunately, the
semi-insulating nature of the silicon nitride matrix, in which silicon clusters are
embedded, severely limit applications. In this project, we propose a novel method to
grow silicon-based quantum dots/nanowires structures, in which the nearly perfectly
two-dimensional ordered identical–size metal nanoclusters will be spontaneously
obtained in Si (111) 7x7 substates ( J.L. Li et. al. PRL 88,0661011 (2002)). We will
use metal-catalyzed quantum dots/nanowire synthesis and repeated modulation of
the reactants methods to fabricate the aligned QDs / nanowire superlattics (Liber, et.
al., Nature 415, 617 (2002)). Our goal is to characterize the photoluminescence,
nonlinear optical properties, electrical transport, and electroluminescence of
QDs/nanowire superlattice structures with a view to potential commercial
applications.




                                          16
Metal/Insulator Tunnel Transistors (MITT) Devices
    Most nano-devices are at a stage of demonstration of principle. They are still a
long way away from being usable in real circuits. As we noted earlier, the transistors
made of CNTs have to be operated at very low temperatures and are difficult to
fabricate in a controlled fashion. SET devices also have to be operated at low
temperatures. Active devices made of self-assembling organic molecules have the
advantage of natural production; however, their present performance is unequal to
devices made by semiconductor technology. Among all nanometer-scale electronic
devices, the metal/insulator tunnel transistor (MITT), which is operated very
similarly to a MOSFET, may be the most promising for immediate development.
    In a MITT, current flowing through a thin tunnel insulator can be modulated by a
gate voltage. The electric field generated by the applied gate bias modulates the
transmission probability through a lateral tunnel barrier between the source and
drain electrodes. When the gate electrode is positively biased toward the source
electrode, the potential at the interface between the metal source electrode and
tunnel insulator interface is distorted to make its profile sharper. Quantum
mechanics tells us that the Fowler-Nordheim tunneling current flowing through the
insulator is strongly affected by the barrier width through which the electrons have
to pass. Thus, this current can be increased by applying a positive gate bias.
Because the transmission probability is exponentially dependent upon the height and
width of the tunnel barrier, a small change in tunnel barrier induced by a moderate
gate bias can result in a large change in current. As we mentioned at the beginning,
the distinction between insulator and semiconductor blurs at the nanoscale.
    There are many advantages of such a device, among which the most important is
the potential for scaling to small dimensions. The fabrication process is also
relatively simple, especially in comparison with other nano devices. In addition, the
maximum operating temperature of such a device is determined by the height of the
tunnel barrier and not by a lithographically defined lateral dimension, as in other
nanoelectronic devices.
    Many research directions remain relatively unexplored. The performance of
MITT devices depends strongly on the potential barrier between the metal and the
insulator. Experiments are needed on various metals and insulators with different
barrier heights. In order for MITT to have a high on/off ratio, the Schottky
emission current should be minimized. It has been observed that the
Fowler-Nordheim tunneling current becomes dominant when the gate voltage is
larger than 1 V. The best achieved on/off ratio of MITT is 105, pretty good for a
device at this early stage of development, but there is still room for improvement.
The subthreshold slope at the present time is about 300 mV/dec, which is poor


                                          17
compared to conventional MOSFETs.


4.2.1.3 Quantum Computation


Single quantum-dot detection and single photon source
      A semiconductor quantum dot is an artificial nanostructure that provides
three-dimensional quantum confinement and results in energy levels that are
atom-like. Coulomb interactions, enhanced by strong carrier confinement, may split
a given energy level into several fine structure states. In single quantum-dot photon
emission, we can observe very sharp multiexciton lines. Using these exciton lines,
we can deduce the interactions of carriers in confined states. We can then apply the
information in these confined states to the design of quantum devices, giving the
possibility of quantum computation. In addition, the energy of photon emission
depends on the number of mulitiexcitons that exist in the quantum dot. When the
recombination time of the multiexciton state is longer than the recombination time
of the free electron-hole pair, we can realize the single photon emission of a
fundamental quantum-dot exciton transition. The single photon source is a stream of
equally spaced photons that in a given time interval contains one and only one
photon. This nonclassical light source is important for the recently proposed optical
implementations of quantum cryptography and quantum computation.

       The samples in our proposed experiment is self-assembled In(Ga)As quantum
dot, which will be grown by MBE in SK mode. The density of the quantum dot
should be controlled to facilitate single quantum-dot detection. We propose to set
up an experimental system of single quantum-dot photoluminescence,
electroluminescence, and photocurrent. For single photon detection, we require a
Hanbury-Brown-Twiss interferometer for photon correlation and time resolution. We
shall try to observe the antibunching of the photon source in single quantum
emission correlation experiments.

Quantum computing
     The physical manipulation of information is a fundamental process that
characterizes the computer age. Information processing relies on the operation of
real physical systems. Although the chip functions in a modern computer already
incorporate quantum mechanical laws in their design and operation, the processing
of the information that the chips manipulate and store still follows classical rules. It
is natural to ask whether any advantages could be gained by processing the
information quantum-mechanically and what features of quantum mechanics could
be used to make a fundamental difference.
     The work of Bell in 1964 on the EPR (Einstein, Podolsky, and Rosen) paradox

                                           18
provides deep insight into this question. Bell's inequality in quantum mechanics
shows that there is a fundamental difference between the correlations among
separated quantum systems and the correlations among separated classical systems.
It is this property that makes the quantum information processing different from the
classical information processing. The realization that the unavoidable disturbance
involved in measurement could be put to practical use leads to the development of
quantum cryptography. Significant progress has been made on this subject both
theoretically and experimentally. On the other hand, the realization that quantum
entanglement is an information resource leads to non-intuitive ideas about quantum
computers and quantum teleportation. It has been shown that there are
computational tasks which could be solved by a quantum computer more efficiently
than any classical computer. However, the number of useful quantum algorithms
which have been discovered remains small. In addition, the quantum information
processors capable of carrying out the computation are restricted to a few qubits.
Many ideas await development in quantum computing. Our own work will focus on:
(1) looking for new quantum algorithms that will do the job more efficiently than the
classical computer, (2) investigating experimental methods that could manipulate
more qubits.



4.2.2    Nanophotonics

     The first commercial product of semiconductor nanostructures is the quantum
well laser. Shortly after the successful production of semiconductor quantum wells,
the advantage of using such structures in semiconductor lasers was quickly realized.
The basic idea was the deformed density of states in a reduced-dimension structure.
Quantum well lasers were demonstrated in the early 80s. Now nearly all
semiconductor lasers use quantum wells for their active elements. Theoretical
studies of the laser performance of quantum wires and quantum dots predicted even
better performance, but premium quantum wire lasers and quantum dot lasers did
not come into existence until the late 90s. The time lag arose from the difficulties in
fabricating high quality quantum wires and quantum dots. The growing of quantum
dots by self-assembly has largely solved the problem of their manufacturing quality.
However, the control of the dots or wires in their shapes, dimensions, and physical
locations is still in its infancy. The future competitiveness of different manufacturing
methods for semiconductor quantum devices will rely on the solution of these
problems.



                                           19
    The program in this category will consist of the following three major areas:
Nanodevice Fabrication, Nanostructure Fabrication and Patterning, Nanostructure
Characterization.


4.2.2.1 Nanodevice Fabrication


Photonic Crystal Device
     Confining and manipulating light in a periodic dielectric media, the so-called
photonic crystal, is a subject of intensive research. The problem is similar to
electrons in a crystal in which the electron energies are grouped into energy bands.
As such, certain ranges of wavelengths in the electromagnetic spectrum of photonic
crystals are forbidden. This property makes this new medium attractive for many
modern applications. Although the idea of crystals with periodic dielectric constants
is quite simple, the fabrication of such crystals remains a challenge. In this part of
the project, we emphasize semiconductor-based photonic materials and devices.
Combining the crystal growth techniques of Sec. 4.2.2.2 with the microfabrication
techniques using e-beam lithography, we hope to produce many useful devices.
     Most of the photonic crystals made today are used for passive devices such as
waveguides, reflectors, couplers. filters, etc.. We will investigate the possibility of
making active devices. An interesting idea is to put the active light emitters or
detectors at the lattice sites of a photonic crystal. If the wavelength of the emitters or
the detectors is in the bandgap of the crystal, the light sources or detectors will
become isolated with minimal cross talk. If the wavelength is in the bands, the light
devices will be coupled. Potentially useful optical interconnects can be fabricated in
this manner.


Quantum-dot light-emitters and detectors
     The devices to be pursued include quantum dot lasers and high temperature
quantum-dot infrared photodetectors. The devices currently fabricated on
InGaAs-based materials will be extended, by the methods discussed in Sec. 4.2.2.2,
to other materials that offer superior performance: higher speed, higher integration
density, and higher operation temperature, but with minimal power consumption.
These devices are expected to give great impact on the electronic and photonic
industry for the years to come. Details are described as follows:
1. Quantum dot lasers: For long wavelength applications, InAs-based and
   GaSb-based quantum dot lasers will be explored with focus on dot density, size
   uniformity, emission wavelength, gain profile, and carrier relaxation. These
   characteristics are closely related to the threshold current, temperature sensitivity,


                                            20
   and modulation speed. GaN-based quantum dot laser, which covers the UV and
   blue spectral range, is also one of the core subjects in our technology roadmap.
   Specific nanofabrication techniques developed for quantum dot formation can be
   implemented according to the requirements of lasers. Heteroepitaxy of GaN on
   Si will also be investigated to improved performance and lower cost of devices.
2. Quantum dot infrared photodetectors: Vertical incident quantum dot infrared
   photodetector operated at 77 K and above is the other key device that is under
   examination. Active region with quantum dots of different compositions will be
   designed for multi-color detection. We will investigate the sensitivity of TE
   and TM modes to the shape of the quantum dots. Last but not least, we will study
   the origins of the dark current of these devices. Preparation of quantum-dot
   active layer with reduced carrier leakage via wetting layer and spacer layer are
   essential to achieve high temperature operation. Material systems used for the
   detectors will include InAs-based, GaSb-based and GaN-based quantum dots.
   The flexibility of using quantum dots of different materials will open up the
   opportunities for various system integration and device applications.


 THz source device
       In the microwave frequency range, the classical theory of electrodynamics is
sufficient to understand the interaction between photons and charge carriers. In the
optical range, the understanding of corresponding interactions requires quantum
theory. Guided by theory, researchers have succeeded in fabricating solid-state light
sources in both of these frequency ranges. However, radiation at frequencies in the
THz range represents an awkward regime where neither the classical theory of
electrodynamics, nor simple quantum theories of light can be straightforwardly
utilized for the design of a laser. This is a contributing reason why so far there is no
THz (far infrared) solid state laser.
      Hot carriers (fast electrons) in semiconductors may provide an empirical
answer for resolving this dilemma in solid state electronics. Amplification of THz
radiation may result from the inversion of specific quantum transitions in a system
of hot carriers. The idea of using inverted systems of free carriers in semiconductors
for the generation of THz radiation is not new. The key task is to achieve population
inversion in momentum space. In 1999, a THz lasers using P-Ge under external
uniaxial stress was proposed and demonstrated experimentally by an international
collaboration involving UST members. The uniaxial stress split the valence band
and the impurity level. When a high electric field is applied to the sample, the
carriers generated by impact ionization are accelerated to a higher energy in the band
that is in resonant with the upper impurity level, causing a population inversion


                                           21
between the split impurity levels. This P-Ge sample was later replaced by a Si-Ge
quantum well structure. The built-in stress provided the pump needed for population
inversion. Under electrical pumping, very strong stimulated emission was obtained
in the frequency range between 2 THz and 10 THz. We expect the lasers to operate
close to liquid nitrogen temperatures. This achievement is the starting point of our
present research project.
      We have already established a THz radiation measurement center with all the
necessary electrical and spectral characterization tools. We have fine epitaxial
facilities for both Si/Ge growth and Ge III-V growth; however, ultimately, we will
not wish to be limited to only the growth of these materials. We have also built-up
a theoretical analysis capability, which is important to this project for the
classical/quantum crossover reasons discussed earlier. In greater detail, we propose
to pursue the following studies:
1. Si/SiGe/Si THz Lasers: To achieve population inversion, we need properly
   designed  -doped layers to create a high electric field in the alloy quantum well.
   Both this electric field and the laser frequency can be tuned by applying a
   transverse bias voltage.
2. THz AlGaAs/InGaAs/AlGaAs Lasers: Larger lattice mismatch and smaller
   binding energy for acceptors, compared to the SiGe case, make it easier to form
   resonant states.
3. Semiconductor Thz Cascade Lasers: We will extend the intra impurity lasing
   mechanism to transitions from excited states to the ground state in the same
   impurity. By a proper design of a series of delta-doped impurities between two
   heavily doped ohmic contacts, carriers tunnel resonantly, under a correct bias,
   from the impurity ground states in one delta-doped layer into the impurity excited
   states in the adjacent delta-doped layer. The subsequent relaxation of carriers to
   the impurity ground states can be accompanied by stimulated emission. This
   process repeats from one delta-doped layer to the next, and cascade lasing is
   realized. We have measured I-V curves of the samples, fabricated according to
   our theoretical modeling, and have confirmed the occurrence of the desired
   physical processes.
     Our mechanism of population inversion requires the delta-doped layers to be
the active region. To increase the pumping efficiency, we must understand the
dynamical processes. This is a new research topic and experimental/theoretical
analysis are needed in the band structure of stressed quantum wells and impurity
states, self-consistent potential profiles, transport of carriers, luminescence spectra
and lasing characteristics, cavity design, and photoconductivity.



                                           22
Spintronic devices

     In today’s semiconductor technology, electron spin has not taken a significant
role, except for its contribution to a factor 2 in the density of states. Traditional
magnetic materials, which utilize electron spin, do not seem to mix well with
semiconductors. But with advances in nanotechnology and growth techniques for
new materials, semiconductor spintronics is coming of age and may become an
important technology of the future. At a minimum, with the additional degree of
freedom, the functionality of electron devices can be greatly increased. While most
of the research in this area concentrates on semiconductors doped with dilute
magnetic impurities, we have been working on semiconductor spintronics without
magnetic impurities. We have found that in some narrow bandgap semiconductor
nanostructures, the spin-orbit interaction can be strong enough to make spin a useful
parameter for device applications. This effect can be controlled by the structure
design and the external electric field. We have investigated spin-dependent tunneling
(through single barrier and through double barriers), spin-dependent scattering, and
spin-splitting without a magnetic field. The results are very encouraging and are well
in the measurable range in today’s technology. The following figure, Fig. 1, shows
the calculated spin-polarized current ratio of a InAs-GaAs-InAs-AlAs-InAs resonant
tunneling structure. Very significant spin-polarization is observed. Such device can
be potentially used as a spin filter.



                                            0 .1

                                                0

                                           -0 .1
                                       p
                                           -0 .2

                                           -0 .3
                                                                    b
                                                                                          a
                                           -0 .4        c
                                           -0 .5
                                                    1       1 .5        2          2 .5       3   3 .5

                                                                        5     -1
                                                                   Fz (10 V cm )

Fig.1 (a). a spin-dependent resonant tunneling structure, (b). calculated ratio of spin
polarized current. Different curves correspond to different external electric field.


     The effects we have investigated are potentially important for future spintronic
devices such as spin-filters, spin-injectors and spin-modulators. As various
semiconductor nanostructures become available and better understood, we plan to
                                           23
work on nanostructures besides conventional quantum dots and wells. We will
extend our investigation to the optical and magnetic properties of quantum rings,
quantum molecules and ordered quantum structures. In particular, we will establish a
theoretical group to do the work mentioned above. This group will also interact with

the activities in the other sections of this program.




4.2.2.2 Nanostructure fabrication and patterning

Self-assembly

      The self-assembly and growth of semiconductor quantum dots depends on the
accumulated strain in the layers that we put on the host substrates. If the substrate is
spatially uniform, the strain distribution is uniform across the wafer as a lattice
mismatched material is put on top of the substrate. When certain critical thickness or
strain energy is reached as the epilayer thickness is increased, random quantum dots
are spontaneously formed. There is basically no preference on where the dots should
be located.

      But if we alter the host material, either in surface topology or strain distribution,
it becomes possible to tailor the distribution of the quantum dots. Different research
groups have used different methods to achieve the selective growth of quantum dots.
We have successfully pioneered the controlled growth of single quantum dots and
single quantum dot arrays on pre-patterned structures using strain engineering. The
following figure, Fig. 2, shows the AFM scanning photograph of the quantum dot
array that we fabricated. The picture shows a regularly spaced array of mesas with a
single quantum dot on top of each mesa. We plan to refine this technique by further
reducing the mesa size and increasing the mesa density. We will explore the
possibilities of using such techniques in optoelectronic device applications, such as a
single dot laser in a photonic crystal resonator. One advantage of this technique is
the improved dot size uniformity. Because of the size and the strain of each mesa are
pre-defined, the dots tend to form with the same size. If the density of the dots can
be increased, quantum dot lasers with very small inhomogeneous broadening will be
possible.




                                             24
                                                    Fig.2 The AFM picture of a
                                                    two-dimensional array of single InAs
                                                    quantum dots grown on top of GaAs
                                                    mesas based on strain engineering




     In most conventional semiconductor quantum structures, the confined regions
have a lower energy than the barriers. There are then confined states in the quantum
structures. Anti-quantum confinement, where the potential energy in the confined
region is higher than that of the outer region, yield a different type of quantum
structure. Many interesting phenomena can be expected from such anti-structures,
but they are seldom studied. We have recently successfully achieved GaAs quantum
anti-dots in InAs matrix. The growth mechanism also depends on the strain build-up
in the epilayer grown on top of a substrate with different lattice constant. It is similar
to the self-assembly growth of the InAs quantum dots in GaAs matrix, but the roles
are reversed. The formation of the anti-dots depends on how much GaAs is
deposited. As the GaAs layer thickness increases from 1.5 monolayers to 2.5
monolayers, the growth changes from a layer-by layer growth mode to the island
growth mode, thereby forming quantum dots. The anti-dots are expected to have
interesting magnetic properties as electrons revolve around the dots in magnetic
fields. Another interesting phenomenon we would like to investigate is the
spin-dependent scattering from the anti-dots. We have theoretically investigated the
spin-dependent scattering in nanostructures and found that the dependence is much
stronger with anti-dots as scattering centers than with quantum dots. We have also
fabricated self-assembled quantum wires (anti-wires) recently. We are able to
fabricate devices with orientation-dependent mobility by burying anti-wires in a
AlInAs/ InGaAs modulation-doped structure. These GaAs anti-wires on InGaAs are
grown on top of InP.

       The arrangement of the quantum structures in a host matrix depends on the
strain distribution and the materials used. If proper care is used, it is possible to
grow quantum structures with a naturally formed regular pattern like a crystal, yet
the structure is artificially designable. So a three-dimensional superlattice of
quantum structures is possible. One-dimensional superlattices have been used

                                            25
extensively in devices with tailored bandgap. Now we can imagine designing a
totally new branch of 3-D superlattice crystals tailored for specific applications.
The possible uses are almost limitless. We are just seeing the beginning of these new
forms of materials made from ordered nanostructures. Further exciting advances are
expected in the future.

       Based on the same principle of InAs quantum dots on GaAs, GaSb/InAs type
II quantum dot pairs will be prepared and characterized. Since Sb is a surfactant for
III-V materials, three-dimensional heterostructures can also be prepared by
modulating the compressive and tensile strain between quantum dots and growth
front in contrast to the vertically aligned InAs quantum dots on GaAs. In this case,
InP and related materials will be involved. GaAs grown at low temperatures is
supposed to contain abundant nano particles from precipitation after thermal
annealing. These nano particles can be used as quantum dot stressors. Another
material system, i.e. GaN, is also a subject of investigation for applications in
nano-devices. Its distinct properties from other III-V compounds, the effect of
growth conditions on the properties of quantum dots, such as size, density, shape,
phase separation, uniformity, and optical quality, can all be studied in detail.

       Regrowth methods via surface engineering can also form patterned quantum
dots. To obtain quantum dot arrays with designated patterns for device applications,
we will explore several low damage techniques to produce surface sites with
morphological or energetic changes for the nucleation of quantum dots. For example,
surfaces with nano-posts or dents result by a combination of e-beam lithography and
dry/wet etching processes. Alternatively, focused ion beams can register a surface
with good precision. As a final example, through a masked surface, a high dose of
As or other ions can be implanted to a specific location on the substrate, thereby
forming localized nucleation sites.

Electrochemical STM

      Certain nano-dot applications require the control of (a) the dot size, (b) the
dot distribution, and (c) the dot fabrication speed. Although quantum structure
fabrication by self-assembly technology is easy to apply, it has drawbacks in the
control of dot size and locations. Scanning Tunneling Microscopy (STM), invented
in 1982 by Gerd Bining and Heinhrich Rochrer, is an alternative to making
nano dots and to characterizing nano-scale materials. The recent development of
multiple tips by Calvin F. Quate of Stanford University, using MEMS techniques,
provides a tool for the mass production of nano devices. We propose altering the


                                          26
conventional STM process to take place in an electrochemical solution environment
(instead of in UHV) to allow dot fabrication on an industrial scale. We believe that
EC-STM (ElectroChemical-STM) provides an attractive solution for the challenge
of low-cost, nano-structure fabrication and patterning.

     EC-STM possesses advantages in allowing the etching and electroplating steps
to proceed concurrently. Furthermore, proper manipulation of the STM can
accomplish many of the necessary nano structure fabrication tasks, because
electrical, physical, and mechanical phenomena are all represented in the
additionally incurred electrochemical reactions. In this project we will fabricate
wide-gap gallium-nitride based films and their quantum-dots structures by EC-STM.
We will adopt techniques like the jump-to-contact method developed by D.M. Kolb
and the Nernst Equation.

    Gallium-nitride based white-light LEDs have proven higher luminescence
efficiencies and longer lifetimes than widely used fluorescent lamps. White light
LEDs may become the major lighting source for daily illumination in the coming
decades. To improve the luminescence beyond 100 lumen/W, to reduce the
operation voltage, and to increase the thermal stability of the GaN based LED, we
will pursue devices exploiting relevant quantum features. We propose to fabricate
GaN quantum dots arrays by the conventional method of MOCVD epitaxially grown
GaN thin film immersed in electrolyte. A scanning tip of a commercial eEC-STM is
used to generate locally the proper electrochemical environment to etch away the
film with a specific etchant or to oxidize the nano clusters. We can also manipulate
the EC-STM to expose some masking layer. The mask pattern can be transferred
to the GaN film by our novel electrochemical techniques, followed by the
fabrication of the desired quantum dots structure. The above mentioned MEMS
techniques can be applied to fabricate the multiple tips used for more advanced
EC-STMs. The following figure, Fig. 3, depicts schematically the proposed device
structure, in which current passes primarily through the dots array, bypassing the
heavily defected GaN layers created by to the lattice mismatch between the substrate
and the epitaxial layers.




                                         27
       Fig.3. Novel device structure for GaN-based quantum dot light emitter




4.2.2.3 Nanostructure characterization

Optical properties

        The optical characteristics of nanostructures are closely associated with the
excitonic states in the systems. We expect the radiation to manifest a coherent
characteristic in cases when systems containing more than one exciton or when the
distance between nanostructures, in which an individual exciton reside, is much
smaller than  , the wavelength of the photon emitted by the annihilation of
excitons. This phenomenon, which earned its name from atomic parallels, is called
superradiance.       The physical origin of superradiance came from the
indistinguishability of identical particles in quantum mechanics. Both the
superradiant decay rate and the frequency shift depend on the effective dimension of
the system and hence contain important information about the nanostructures. The
decay rate of the exciton will be enhanced by the breaking of the crystal symmetry.

For instance, the enhancement factor is  d in a linear chain, and  d  in a thin
                                                                           2



film, where d is the lattice constant of the chain or the film. Further enhancement
is expected if the nanostructures are embedded in a microcavity. We propose to study
the superradiance characteristics of arrays of quantum dots, wires, and rings.

Quantum transport properties

       Finite-frequency quantum-transport characteristics of nanostructures provide
an effective way of probing the quantum states in the structures, as well as inducing

                                          28
coherent dynamical quantum processes in them. The ac signal can be coupled to
the nanostructures via photons or ac biased side-gates. The frequencies of interest
range from hundreds of MHz. to hundreds of GHz. This research field is still in its
infancy and is expected to expose new phenomena and insights about the
microscopic nature of nanostructures. In the case when an ac biased side-gate is on
top of a quantum point contact, the conductance G is predicted to exhibit resonance
characteristics that correlates with the frequency, the Fermi energy, and the subband
bottom. A coherent inelastic scattering by the traversing electron occurs into its
sideband, and its energy is lowered by n . In addition, we have predicted such
ac biased side-gates to cause new resonances in G, when fabricated in numbers
larger than one, evenly spaced, and situated on top of a narrow channel. An ac
version of Bragg’s reflection provides an explanation. The ac biased side-gate
technology, when applied to coupled quantum dots, can cause an electron to make a
transition from an energy level in one dot to an energy level in another dot. Subject
to the alignment of the Fermi level, this could give rise to a transport current even
when there is no source-drain bias. Thus, the finite frequency quantum transport,
enabled by the ac biased side-gate technology, is effectively a spectroscopic probe
for the quantum states in the system. We will develop this ac biased side-gate
technology and establish the corresponding transport characteristics in quantum dots,
wires, and rings.

        A study on the effects of photons upon the quantum transport in
nanostructures such as quantum point contacts can lead to the design of a
frequency-tunable photon detector. Again, the frequency of our interest ranges from
hundreds MHz. to hundreds GHz. A previous experimental attempt, by Alamo et al,
had the entire structure─including both the source and drain electrodes─exposed
to the electromagnetic (EM) field. Bolometric effects interfered with the
interpretation; the heating of the electron gas at the electrodes masked the possibility
of observing photon-assisted quantum-transport features. New configurations are
needed. We thus propose to deposit two separate metallic thin films on top of a
narrow channel, leaving a gap between the two films. These thin films will function
both as a protection against the source underneath and the drain electrodes and as an
antenna coupling to the EM field. The submicron-sized gap and vertical separation
warrant that the narrow channel is within the near-field regime and hence is exposed
only to an EM field with a more localized profile. Our prediction is that the dc
conductance G is sensitive to both the frequency and the intensity of the EM field.
With the additional implementation of split-gate technology, we can tune the
effective width of the quantum point contact, which will allow us to monitor the
frequency of the EM field. Thus, we hope to use the effect for the design of

                                           29
frequency-tunable photon detectors.




4.2.3 Nano-Bioelectronics and Bio-Nanotechnology

     Biological systems have a unique ability to control the phase, orientation, and
topographies of nanostructures. In addition, biological macromolecules have several
advantageous properties such as their intrinsic nano-scale dimensions, little gate
propagation delays, repetitive features, recognizable motifs, precise scaffolds for
self-assemblage, and high specificities in binding and catalysis. These properties
have made biological macromolecules ideal targets for industrial applications in the
fields of nanobioelectronics. Much of the research effort in bioelectronics is
directed toward self-assembled monolayers, thin films, biosensors, and
protein-based photonic devices.

     Bionanotechnology focuses on the construction of artificial cell growing
environments, which are extremely complex 3-D structures in the micrometer to
nanometer range. Clinical and experimental investigations have reported that
cellular topographies have significant effects on cell function and tissue integration.
Topographical cues, independent of biochemistry, generated by the extracellular
matrix, for examples, affect cellular activity. Scientific study has also documented
that cell growing substrates directly influence the ability of cells to orient themselves,
migrate, proliferate and even differentiate. The fabrication of such biomimetic
substrates can be based on many different types of materials, including polymers of
synthetic and biological origin. The resulting “cell/tissue architectures” may find
both research and clinical applications.

      Concurrently, advances in optical techniques and high-performance
photon-detectors have made possible the rapid, precise, and high signal-to-noise
ratio detection of single biomolecules. The frontier of single-molecule study in
biotechnology is attracting worldwide attention. This field provides an unparalled
opportunity for innovation in biomedicine. The techniques of detection and
characterization involve the trapping of single molecules, perhaps using laser light,
followed by nano-scale measurement and mechanical perturbation, in which
complicated assay concepts and theoretical analyses are cross-relevant, and open to
the joint efforts of many disciplines.

     Single molecule biotechnology can roughly be divided into two regimes: one is
the single molecule detection (including spectroscopy); the other is the single

                                            30
molecule manipulation. At the beginning of our project, we will choose a
florescence resonance energy transfer (FRET) detection system and a laser tweezers
system for each regime. A complete single-molecule research program will require
diverse instrumentation techniques including micro-imaging, detection, spectroscopy,
measurement and manipulation. For our proposed research team, we have gathered
many scientists specializing in biology, biochemistry, photoelectrics, precision
mechanics, micro-electromechanics, data analysis, and system integration.

4.2.3.1 Researches on the key technologies of nano-bioelectronic devices

     In this program, two classes of nano-bioelectronics are subjects for detailed
study: (1) “DNA bridges” for computer and molecular switch applications; and (2)
enzyme-based bio-logic gates, bio-transistors, bio-memories, and bio-fuel cell devices
and their possible applications in controlling the electronic signal flow in electronic
computers and telecommunications switching systems. We will also explore, at the
same time, the interface in handling, connecting and transporting the biological signal
among different bio-electronic devices.

DNA-based molecular electronics

      We propose to study “DNA bridges” for computer and molecular switch
applications. The DNA computer will contain the following specific features:
intrinsic nanometer scale, neural network-like approach to solutions, and massively
parallel action of in vitro biochemical reactions. Specific aims for the subproject
will include the designing of oligonucleotides, microchip design and manufacture,
immobilization of alkanethiol-capped oligonucleotide on Au electrode of chip,
assembly and functional analysis of the DNA-based nano-bioelectronic device, and
applications of such novel devices. In the first stage of this project, we will study
the effect of DNA length as a function of DNA topology. We will apply DNA
engineering techniques to create DNA molecules with specific topologies, shapes,
and arrangements of secondary and tertiary structures. We will measure the
melting point, rigidity, and spatial complementarily of DNA molecules. We will
also set up an atomic force microscope for monitoring the self-assembly of DNA
and DNA-directed assembly of protein.

     In the second stage, we will investigate the DNA-directed immobilization of gold
nanoparticles for supramolecular surface architecture formation. We will use
specific nucleic acid hybridization to immobilize gold nanoparticles on solid supports.
The colloidal gold nanoparticles will be applied to enhance the signal detection.
Following the design/synthesis of self-assembled DNA and the immobilization of the
                                          31
gold-linked oligonucleotides, we will examine the molecular switch properties of
DNA bridges by adjusting the temperature or the electric field. When the
temperature or electric field is controlled below some critical point, namely Tm of
DNA, the bridge is paved with a series of short DNA fragments. Alternatively, if the
temperature is above the Tm, hydrogen bonds, which lead to the self-assembly of
DNA, will collapse to hold a high-impedance circuit. By changing the temperature
or electric field in a suitable range, we can turn the circuit on and off periodically.

Enzyme-based nano-bioelectronics

     Specific aims for this project include the design and generation of repetitive
and recognizable protein motifs, optimization and assembly of enzyme systems,
immobilization of protein to the electrode surface, biocatalysis and biosensing, and
applications of such devices in bio-electronics and medicine. In the first stage of
this project, we will apply protein-engineering techniques to construct protein
modules with specific binding, catalysis, electron transfer, or molecular Lego
properties. Specifically, the redox proteins and photo-transducing enzymes will be
subjected for protein module design and engineering. We will examine these
protein modules for binding, catalysis, and electron transfer properties. We will
also investigate the pH optimal, thermal stability, and substrate affinity of these
protein modules.

      In the second stage, we generate and test enzyme-based bio-logic models, based
on the specific regulation of the catalytic activity of enzymes by substrate
concentration, pH value, and anti-oxidants/radical scavenger, to mimic Boolean logic,
i.e., YES/NO, AND/OR and XOR/NXOR. The catalytic or electron transfer
modules of specific redox proteins will also be genetically or protein engineered to
build self-assemblages with improved electrochemical or energy transfer properties.
Combinatorial phage display techniques will be applied to generate peptides that can
recognize different semiconductor alloys and gold-binding proteins.

     Experience obtained from preliminary research and a literature search for
bio-memory devices showed that there are many obstacles before the integration
between biomolecule and semiconductor can actually happen. Signals between the
two need to be transferred by physical pathways interpretable by both. We have
examined many methods using variations of light, heat, acid, and alkali. For
example, the protein of bacteriorhodopsin has the property of translations in its
structure after the absorption of radiative energy. In addition, its photo-absorptive
sprectrum is changed. Thus, we can do the operations of read and write in


                                          32
bacteriorhodopsin by using light. Furthermore, this kind of memory is relatively
nonvolatile because the proteins have the property of stability. Rough estimates
show that the density of this memory will be larger than that of DRAM.

     We will also perform nano-bio-transistor research through the integration of
oxidoreductase-catalyzed reaction with the redox state change of conductive polymers
to generate an enzyme-field effect transistor for conductivity changes. We will apply
molecular directed evolution or molecular Lego approaches of oxidoreductase to
improve the sensitivity and reduce the reaction size to nano-scale. Although practical
systems may be some decades away using nano-bioelectronics, the time is ripe now to
do the basic research.

Microfluid delivery platform design

     In this section, we propose to study the technology of manipulating nano-scale
fluid channels between different bio-electronic devices. We will apply a novel polar
capillary method to manipulate nanoliter amounts of fluid. Capillary action is a
natural phenomenon, especially effective in small tubes or channels; therefore, it is a
perfect candidate for moving nano fluid systems. Recently, by combining MEMS
technologies, researchers have reported several methods to control fluid movement in
microchannels, including thermocapillary and electrocapillary action. In the first
method, the key concept is an uneven surface tension at the two ends of a droplet
subjected to a large temperature gradient. The uneven surface tension then drags the
droplet along the microchannel. Unfortunately, the thermocapillary method is not
unsuitable for enzyme or protein handling due to their sensitivity to temperature
changes. The electrocapillary, method relies on Lipmann’s principle: an uneven
surface tension is induced by a nonuniform distribution of electrical charge in double
layers. However, the thickness of the electro double layer often requires unrealtistic
input voltages or unusual properties of the working fluid.
       In contrast, the polar capillary method is based on the polarization of the
working fluid by two electro plates. The surface properties of the electro plates from
hydrophobic to hydrophilic can be changed through polarization. Consequently, the
fluid in the channel can be driven by control of the polarization state. Several
advantages, including reduced electrolysis effect, low temperature effect, and simple
fabrication make the polar capillary method the ideal method to integrate
bio-electronic devices and serve as the I/O interface of a nano-bioelectric system.

Future prospects and applications

   The fusion of biotechnology with the electronic industry has great potential for
                                          33
generating advanced technology and novel devices as well as for reducing their sizes
to nano-scale. Therefore, the integration of different research expertise provided by
this research team will further the construction of nano-bioelectronic devices and
materials to complex atomic specifications as well as the characterization,
manipulation, and repair of biological materials.

4.2.3.2 Manipulation and detection of the single biomolecule

   Single-molecule observation and manipulation have offered new tools for the
study of individual macromolecules, rather than ensemble averages, under
physiological conditions. These techniques provide time-resolved information and
spatial localization of single molecules and allow powerful insights into the kinetic
and dynamic behaviors of genetic materials and proteins.

 Laser tweezers system

     A new tool, laser tweezers (or “laser trapping”), made by focusing a laser beam
to a diffraction-limited spot, provides a means to generate and measure molecular
scale forces for the study of individual biomolecules, allowing experimentalists to
perform physiology at the macromolecular level. It has been proved important in the
micromanipulation of living cells, bacteria, protozoa, intracellular organelles,
chromosomes, microbeads, and liposomes. Owing to the versatile abilities of
micromanipulation, researchers have begun to use this tool to probe the molecular
details of such diverse activities such as vesicle transport, muscle contraction, and
RNA transcription. Laser tweezers designed for work with single-molecule assays
should have the following desirable features.

1. Imaging can be done at high magnification and with the greatest possible
   resolution. This means that the use of high numerical aperture, oil/water immersed
   objectives and condensers, epi-fluorescence-, video-enhanced-, and differential
   interference contrast-microscopy are all needed;
2. The microscope should be equipped with one or more optical traps, each capable
   of independent motion within the field of view;
3. Sensitive position detectors for objects trapped by the system are required;
4. The development of a precision feedback control system to create an isometric
   position clamp is necessary;

      Laser tweezers system designed for the single-molecule assays are extremely
sensitive to both mechanical and acoustic vibrations, and must be mounted on air
isolation tables. In addition, it helps to place such systems in clean rooms with good

                                          34
temperature control.

Fluorescence resonance energy transfer system

     The technique of fluorescence resonance energy transfer (FRET), extensively
explored due to the progress of dye techniques and optical detectors, needs two
fluorophores. These can be either naturally occurring or artificially introduced on
tagged biomolecules. The fluorophores may be located at two different sites of the
same molecule or on two different molecules. A donor fluorophore is excited by
incident light. The excitation energy can be transferred to an acceptor, appropriately
selected by its energy spectrum, which is in close proximity to the donor. This leads
to a reduction in the donor’s fluorescence intensity and excited state lifetime, and an
increase in the acceptor’s emission intensity. The efficiency (E) depends on the
inverse sixth-distance between donor and acceptor: E = 1/[1 + (R / Ro)6] where Ro is
the distance at which half of the energy is transferred.          It also depends on the
spectral characteristics of the dyes and their relative orientation.

      The effect can be used as a spectroscopic ruler: by measuring E and knowing or
calibrating Ro, the distance R can be inferred. Because Ro is typically 20–60 Å,
distances on this order can then be measured. The FRET is of particularly important in
studying the 1) localization of a macromolecule labeled with a single fluorophore F
with nanometer accuracy, 2) colorization of two macromolecules labeled with two
noninteracting fluorophores, 3) intramolecular detection of conformational changes by
spectroscopy-FRET, 4) dynamic colorization and detection of association or
dissociation by intermolecular spectroscopy-FRET, 5) fluctuations of protein structure
and enzyme-substrate interactions during catalysis. Fluorescence resonance energy
transfer system designed for work with single-molecule assays need to have the
following desirable features.

          a.   a small excitation volume (to reduce the background),
          b.   high-efficiency collection optics,
          c.   detectors with high quantum efficiency and low dark noise;
          d.   elimination of background fluorescence by various means such as a
               pinhole in the conjugate plane, prebleaching of impurities in the solvent,
               and using very low-fluorescing optical materials along the light path of
               the equipment.

Combined studies employing the laser tweezers system (single-molecule manipulation)
and the fluorescence resonance energy transfer system (single-molecule spectroscopy)
will be especially emphasized in the bionano science of the Center.
                                           35
DNA CD-ROM sequencing

      Despite public perceptions to the contrary, the international race to sequence
the human genome is an ongoing enterprise. One effort is to decode from a single
copy instead of thousands of copy because the former has the potential to speed up
the sequencing process. The other is to extend the length of sequencing segments
from 1k base pairs to 50k, which would simplify and accelerate the task of
reassembling the complete linear chain. The workhorse technique of both efforts is
the protein “exonuclease,” which degrades DNA bases one by one. Two difficulties
have emerged in the agenda: (1) how to control the speed of exonuclease and (2)
how to identify them. One of our strategies is to control the degrading by laser
energy trigger and to address them by a CD-ROM system using single-molecule
manipulation techniques. The CD-ROM backbone is chosen because it is a mature
technology, alleviating us of most of the burden in precision control, fast
localization etc. We can also readily access the support facility locally in Taiwan.

     Our contribution to any sequencing effort will focus on providing the
following single molecule capabilities:

1. Laser tweezers system:
        a. Basic setup: inverted culture microscope, precision workstation, laser
            scissor and laser tweezers.
        b. Complementary setup: micropipette, micro-flow chamber, high
            performance charge-coupled device (CCD) camera.
2. Fluorescent Resonance Energy Transfer:
        a. Basic setup: fluorescent microscope, laser systems, pinhole, filter,
            photomultiplier tube ( PMT).
        b. Complementary setup: avalanche photo-diode (APD), total
           internal-reflection (TIR) and surface plasma resonance equipment.
3. Sample preparation (collaboration with other core facilities):
        a. Isotope labeling and chemical dye labeling bench.
        b. Cell culture.
        c. Protein and DNA preparation.
4. Single molecule based ultra-fast/precision DNA sequencing
5. The combination of techniques below:
        a. Motor dynamic observations: actin-ATP-myosin, RNA polymerase,
            microtube-kinesin-spindle.
         b. Force measurementc.
         c. Manipulation of biomolecules: folding/unfolding of proteins and RNA.

                                         36
Single-molecule biomedical research

      Examples are given below of the kinds of biomedical research that can be
exploited by single-molecule detection and manipulation techniques. Items 1 and 2
represent topics for immediate investigation by our group.

 1. Collateral radiation damage is an important issue both in environmental and
    therapeutic contexts. Radiation dosimetry research has progressively moved
    from macro-dosimetry to micro-dosimetry to nano-dosimetry. Using a laser
    tweezers technique, we can measure the occurrence of DNA single-strand
    breakage and DNA double-strand break under different irradiation conditions,
    e.g., an environment with a high free-radical content.
 2. During the viral infection process, some proteins inside the virus envelope will
    come into contact with the host cell membrane through the pores of the
    envelope. X-ray studies can show the proteins attached to the pore. The
   snapshot character of the X-ray crystal photography means, however, that the
   dynamical processes of protein behavior remain hidden. Knowledge of this
   dynamic process has import for the understanding of and the prevention of
    infection. This knowledge is accessible through a combination of optical
    tweezers and single molecule FRET techniques.
 3. Correlation studies of the following would be valuable: between the
    conformational changes of an ion channel protein with the fluctuations of ionic
    current, and between the displacements and conformational changes of a
    DNA-processing protein (such as: DNA polymerase, nuclease).
 4. Macrophages infected by cytomegalovirus (CMV) become infectious when
    they contact fibroblast cells. The laser tweezers technology is able to bring two
    cells into direct contact. In combination with a FRET system, it is then feasible
    to observe how fluorescent-labeled CMV DNA is transferred from one cell
    (macrophage) to another (fibroblast). In addition, specific gene expression
    pattern of a single fibroblast cell infected with CMV can be detected.
 5. A hypothesis exists that electromagnetic waves might influence the activity or
    conformation of membrane receptor protein(s). This hypothesis can be tested
    by using single molecule techniques.

4.2.3.3 Cell/tissue engineering utilizing nanotecnology

      The construction of the biomimetic system for stem cell research, and artificial
liver and neuronal regeneration stands as the central goal of this project. We aim to
understand the functional domains of organismal cell/tissue activities, learn how


                                          37
employ microstructures and nanostructures in biological sysytems, and use this
knowledge base to design and synthesize new materials and devices for biomedical
applications.

Setting up biological assays to establish functional domains of organismal
cell/tissue activities

    To initiate the program, we will set up biological functional assays for
quantifying biological activities, such as cell adherence, substrate-induced cell
morphogenesis, proliferation, differentiation, secretion, and neuritis outgrowth.
Selective assays will then be utilized to build an experimental platform that addresses
the functional consequence of the topographic features on cell growing substrate.

Fabrication of the topographies of cell growing environment

     The control of the chemistry and topography of the substrate to which cells
attach is central to this part of the research. Success of this section would pave the
technical way for the accomplishment of the ultimate of goal of this program, i.e., to
use cell architecture and tissue engineering, in biomimetic systems.

     Surface characteristics play a major role for controlling the biocompatibility of
the biomaterials. Recent findings in cell biology have revised our concepts of
scaffold design, especially that of molecular motifs displayed on the surface. The
molecular cues deposited on the cell-growing substrate could be adhesive,
anti-adhesive, or related to the active ECM components for signal transduction. By
carefully designing the outlay of these molecules on the template, we could implant
the resulting material to modulate tissue regeneration or to act as a biosensing device.
We have developed various methods of surface modifications. By using these
techniques, we are able to control the following surface properties of biomaterials:

     1. different degrees of hydrophilicity and electric charge,
     2. grafting with linear as well as cross-linked macromolecules,
     3. patterning using stamp coating techniques originally developed by G.
        Whiteside.

     We are hence in a good position to create templates with various surface
patterns and to study the behaviors of cell adhesion and cell growth on these
templates. To investigate the effects of patterned surface on the phenotypic
expression of the cells grown on the template, we will characterize the nano
structures of these templates by ESCA, SIMS and AFM. Surface analyses using

                                           38
AFM operated in aqueous phase are especially informative in providing a tomogram
of the material in a state close to that in tissue. We can also obtain information
related to the mechanical properties of the material surface, which are key elements
in affecting the behavior of cells on the templates.

     The fabrication techniques proposed in this project enable the researchers to
position biomolecules and/or cultured cells at specific locations, and in certain
orders to create organized structures. Information obtained by these new
approaches may also shed light on issues of fundamental importance in cell biology.
Photolithography is one of the most extensively used techniques for patterning
distributions of biological molecules, such as proteins. Although photolithography
is a well-developed method, most biomolecules lose their activity following the
surface chemistry of conventional photolithographic protocols. We have recently
adapted an alternative method using elastomeric stamping to fabricate the culture
substrates.    This technique can be carried out conveniently, rapidly, and
inexpensively for relatively large features that are commonly encountered in biology
laboratories.

      In addition, supramolecular and self-assembling structures can be employed to
generate nanostructures, and for the construction of the three-dimensional architecture
of cell growing environments. Microfluidics and microelectromechanical systems
(MEMS) considerations influence the effective design and implementation of modern
bioarchitecture systems, as well as bioanalytical chemistry. MEMS devices can
potentially handle and manipulate biosamples in a much more efficient way than
conventional instruments.           We will employ increasingly sophisticated
microfabricated devices with greater functionalities developed in the other sections of
this cross-disciplinary research that are complementary to the studies proposed here.

Construction of cell architectures and biomimetic systems

     The development of the proposed bioartificial systems useful to stem cell
research and organ regeneration involves the design, modification, growth and
maintenance of living tissues embedded in synthetic scaffolds to enable them to
perform complex biochemical functions, including adaptive control and the
replacement of diseased tissues. To achieve this goal of the rational production of
precisely formulated nanobiological devices, one would need to consider at least the
following issues: (1) use of molecularly manipulated nanostructured biomimetic
materials; (2) application of microelectronic and nanoelectronic interfacing for
sensing and control; and (3) application of nanosystems to induce, maintain, and


                                          39
replace a missing function that cannot be readily substituted with a living cell, and to
accelerate tissue regeneration.

Expected Results and Applications

    Nanostructured tools should encompass surface patterned molecular arrays,
nanoscale synthetic scaffolding mimicking the cell-extracellular matrix
microenvironment, precise positioning of molecules with specific signals to provide
microheterogeneity, composites of bioinorganic and organic molecules, molecular
layering (coating), and molecular and supramolecular self-assembly and
self-organization (template-directed) assembly.        The nanoelectronic interface
includes electronic or optoelectronic biointerfaced devices based on individual cells,
their aggregates and tissues, organelles, and molecules, such as enzyme-based devices,
transport and ion-channel membrane proteins, and receptor-ligand structures,
including nanostructured semiconductor chips and microfluidic components.
Delivery nanosystems encompass both water and lipid core vehicles (for hydrophilic
and lipophilic components) of various geometries: liposomes, micelles, nanoparticles,
lipid shells (as imaging and contrasting agents), solid nanosuspensions, lipid
nanospheres, and coated film surfaces (molecular layering), all for use in delivering
drugs, proteins, cell modifiers, and genes. Nanoelectronic interface and delivery
nanosystems can be used for sensing, feedback, control, and analysis of function of
bioartificial systems.




4.3 International Collaboration

     The Center of Nano Science and Technology will seek collaborative
opportunities with leading research institutes worldwide. The collaborations take the
forms of cooperative research programs, exchange of scholars, exchange of students,
information sharing, and resource sharing. In the nanoscience community, Taiwan
cannot be isolated from the rest of the world. In this field, we are still behind the US,
Japan, and some European countries. We have to rely on international cooperation to
jump start our own programs. As members of the international community, we also
have an obligation to contribute to world knowledge and to make ourselves active
participants in this important field.

      All four members of this university system have their own International Affairs
Office, which have signed agreements with many foreign universities and research
institutes. With the establishment of this nanocenter, we will consolidate the

                                            40
collaborations to give the programs more focus. We have been contacted by several
leading institutes on nanotechnology, including the National Research Council of
Canada and the Air Force Office of Scientific Research of the US. Some of the
proposed research collaborations have reached fruition; others are being formulated.

     We will also invite scholars from other countries to come to the Center to
participate actively in our research programs. These scholars could be either
well-known scientists providing guidance in the research direction or young
post-doctors adding to our overall research capability. One successful example is the
THz project, where we collaborate with scientists from Sweden, Russia and the
Ukraine. Not only have we achieved excellent results, but we also established a THz
radiation center at NCTU because of this collaboration.

4.4 Industrial collaboration

     The high-tech industries of Taiwan are continually seeking opportunities to
expand into advanced product areas. Part of the reason for their past success is their
willingness to take risks in new product development and then quickly moving
ahead. They must be part of the nanotechnology revolution in Taiwan and play an
active role if it is to happen. Proximity to HSIP gives the Center an ideal location
to coordinate the efforts in training, directing, planning, and incubating the spinoff
nanotechnologies that these high-tech companies crave. The research outputs from
CNST will easily find application opportunities through cooperation with the
development activities of companies in the science park. Technology transfer to
industries will not only bring financial benefits to UST, but will also help the Center
to focus on technologies that have real applications.

     CNST will also work closely with ITRI, which is the main player in Taiwan for
industrial research for nanotechnology, and with Academia Sinica, which is the
foremost institution for basic research on the island. NTHU operates a joint center in
MEMS and Nanotechnology with ITRI, and Academia Sinica cooperates with the
four campuses of UST on a wide variety of basic research problems. Signed
agreements exist, and several planning meetings and workshops have been held to
discuss issues and research projects of future collaboration in nanotechnology.
NCTU and NTHU have also started a training program on nanotechnology for ITRI.
Fundamental subjects, such as quantum mechanics, solid state physics, and
introductory material science, as well as advanced courses in semiconductor
quantum devices, nanofabrication, and nanostructure analysis will be offered.



                                           41
      Apart from ITRI and Academia Sinica, several nearby national research
institutions will also be our partners in the research and development of nano
science and technology. The Synchrotron Radiation Research Center (SRRC),
which has the best quality X-ray source in the country, will work with us on surface
analysis, structure analysis, and microfabrication. The National Nano Device
Laboratory (NDL), which is operated by NSC and located in the campus of NCTU,
will collaborate on the development of the next generation of nanoelectronic devices.
They have many state-of-the-art device processing equipment that will prove
invaluable. The National Center for Theoretical Sciences (CTS), also under NSC but
located on the NTHU and NCTU campuses, will collaborate with us on the theories
of nanostructures. The National Center for High-Performance Computing (NCHC),
which has the best computer facility in the country, will provide us with the
computer power that we need for the numerical analysis of nanostructures. The
Precision Instrument Development Center (PIDC), which is the scientific instrument
development center, will cooperate with us on the development and setting up of
instruments and laboratories for the Center.         Combining the human and
instrumental resources of these five national research centers with those at UST,
ITRI, and Academia Sinica, will make the basic research, applied research, and
industrial development of Taiwan in nanotechnology competitive with the
capabilities of the best R & D groups in the world.




4.5 Education

     Apart from research, the most important mission of NCST is to educate and to
train students in the new area of nano science and technology. Because of the
multi-disciplinary nature of nanoscience, the traditional departments, either in
engineering or in natural science, cannot provide a broad enough educational
platform for Taiwan’s students. The Center will help the UST to formulate a
graduate-level curriculum that leads to Master and Ph.D degrees in nano science and
technology. With the participating professors from our four campuses, we will be
able to offer a wide variety of courses related to the nanosciences. Three different
tracks leading to specialties of nanoelectronics, nanomaterials and
nanobiotechnology will be offered. A sample of the course list for the three tracks is
shown in the following table.




                                          42
Common courses            Nanoelectronics            Nanomaterials              Nanobiotechnology
Introduction to nano-     Semiconductor devices      Synthesis of nano-         Engineering Bio-
sciences;                 and physics;               materials;                 materials;
Introduction to materials Solid state physics;       Surface chemistry;         Molecular Sensors and
sciences;                 Quantum transport          Analysis of nano-          Nano-devices;
Quantum physics;          theory;                    structures;                Cell and Tissue
Physical chemistry.       Low-dimensional            Solid state chemistry;     Engineering;
                          semiconductor devices      Structures of materials;   Bioinformatics;
                          and physics;               SPM and applications.      Genetechnology;
                          Optoelectronic devices;                               Biochemical Engineering;

                          Quantum computing;                                    Biophysics.
                          Spintronics.




The students in this program can select the subject they are interested in for their
thesis research and may choose any of the professors of the Center as their research
advisor. We will actually encourage professors from different disciplines to team up
in the joint supervision of graduate students and postdoctoral fellows. Through our
collaborative programs, our students will be able to gain further exposure to the
diverse forms of frontline research being carried out worldwide in nano science and
technology.




5. Expected Results and Achievements

5.1 Cost-effective research at the frontiers of nano science and technology

       The joint effort by four campuses will result in considerable cost savings. The
sharing of equipment, lab facilities, manpower, and administrative support will
facilitate more cost-effective research. Because the research programs are centrally
managed, unnecessary administrative overhead will be minimized, and duplicate
effort will be avoided. Equipment and lab spaces will be used more efficiently.
With the establishment of the dedicated core facility for nano science and
technology, most of the routine processing work and analysis work will be done in
one place and overseen by dedicated personnel. On the other hand, individual
research programs will retain the flexibility and quick response capabilities of a
distributed system.

                                                    43
      Within the UST, the four campuses have agreed that Chiao Tung University
will share its semiconductor processing facility, Tsing Hua University will share its
material analysis facility, Central University will contribute its optical measurement
capability, and Yang Ming University will have its medical and biological facilities
and faculties available for us to use and to consult.

5.2 Education and training in nano science and technology

      With around 150 faculty members actively participating in the nanoprograms,
we anticipate that we will have approximately 1200 master students and 600 Ph.D
students enrolled at any time doing thesis research in the field of nano science and
technology. This means that we can graduate 600 masters and 150 Ph.Ds each year.
This output of highly trained personnel should make a large impact on the
nanotechnology development of Taiwan.

      We will also provide on-the-job training courses for personnel working in
industry. A prototype program is the offering for ITRI employees. Each year we will
teach three 14-week sessions; each session has three course offerings. If on average
50 students attend each course, we will teach 450 person-courses each year. This
type of program will be extended to the engineers and scientists in HSIP. We can
then anticipate that we will provide training at a rate exceeding 1000 person-courses
per year in the field of nano science and technology.




5.3 Impact on nano industry

     An industry without the support of academia has no roots and cannot prosper
                                        very long. The foundation of the successful
               CNST                     electronic industry and the science park in
                                        Taiwan was laid when NCTU and NTHU
                                        were established more than 40 years ago.
                                        The people who contributed to the
                                        manpower behind this success are the
     SP                      ITRI       professors and the students who spent
                                        numerous hours in the laboratories. The
                                      nano industry, if it is to achieve its promise
                                      in Taiwan, will have to follow a similar path
of development, growth, and maturation. NCTU and NTHU are now joined by NCU
and NYMU. As a consequence, the team is stronger in both research and teaching,

                                          44
and this university system can be the driving force that integrates the nano science
effort of Taiwan and pushes its associated nanotechnology into the real world.

    The Center for Nano Science and Technology of the UST, when combined with
ITRI, HSIP, and Academia Sinica will form a circularly integrated Research-
Development-Commercialization chain as shown in the preceding figure. The
innovations generated by our researchers will turn into profitable commercial
products through this chain. The profit produced at the end will support more
advanced research through the partnership between industry and academia.




6. Core facility

       Nanoscience and technology cover a wide variety of disciplines requiring
different kinds of research tools. Because of the accuracy and precision needed for
the fabrication and manipulation of nanostructures, special and often expensive
instruments are required.

     The Center will have a central facility equipped with commonly used
processing, analysis, and testing equipment. Other specialized equipment will be
housed in individual laboratories in different universities. Some of the instruments
are given in the following list:

Central facility:

1. Clean room for nanofabrication
2. Basic semiconductor processing eqipment
3.   Atomic force microscope/scanning tunneling tunneling microscope
4.   TEM, SEM
5.   Focus ion-beam machine
6.   X-ray diffractometer
7.   E-beam lithography

Other laboratories:

1. MBE for semiconductors doped with magnetic impurities, MBE for high purity
   and high mobility materials
2. Low temperature I-V measurement system
3. Time resolved PL system


                                         45
4. Cluster beam synthesis system
5. Neutron scattering spectrometer
6. Single molecule manipulation system
7. Molecular imaging system (high resolution CCD, Zetasizer, etc.)
8. DNA and protein facility
9. SNOM/SPM/Micro-Raman system
10. Nanoparticle size analyzer
11. Low temperature magneto-optical measurement system
12. Biological SEM
13. Low temperature near field spectroscopy
14. Confocal microscope




7. Budget and Personnel

7.1 Budget

   The total budget is shown in the following table.    The numbers are in units of
   NT$ 1,000 .
                                    1st year       2nd year         3rd year
                Lab remodeling       10,000            30,000       20,000
                   Equipment        100,000            90,000      112,000
                   Personnel         5,000             15,000       30,000
                      Misc           15,000            15,000       20,000
                      Total         130,000        150,000         182,000

7.2 Personnel

    The Center will have a Director and three Associate Directors in charge of the
overall operation of CNST. Each functional branch will have a Coordinator. Under
the arm of individual research projects, each research department will have a
Program Manager responsible for program execution. All the Coordinators and the
Program Managers will be professors who are members of this Center. The actual
research programs will be carried out by professors and their students and postdocs
on the four campuses of UST. The estimated number of UST professors who will
participate in the nanoprograms is around 150. There will also be visiting scholars,
postdocs, and students. These personnel plus their overseas and on-island



                                         46
      collaborators form the research force behind the Center. The headcount for all the
      UST departments is listed in the following chart.




                                              CNST


                                         Center director 1
                                                                         Secretary 1
                                         Associate director 3

                                                333



Coordinator 1        Coordinator 1          Coordinator 1                 Coordinator 1         Coordinator 1
 Education          Common facility       Research programs           Research collaborations   Administration



                                           Program managers                  Assistants          Assistants
                    Lab manager 1                  4                             2                   2
Assistants 2


                                                      Faculty
                                                       150
                    Technicians 5

                                                      Vistors
                                                        10


                                                      Postdocs
                                                         50


                                                      Devices
                                                      Ph.D students
                                                          500




      8. Self-Assessment of the Participating Universities


      8.1 National Central University

      National Central University was known as the earth and physics research university
      in the country. In order to develop its uniqueness, NCU extended its research
      program to optoelectronic devices and material science in the last couple of years.
      NCU has strong device fabrication teams and spectroscopic characterization groups.
      NCU recently established a micro optoelectronic laboratory that provides capability
      to fabricate micro-optical components such as microlens, micromirrors, and
      diffractive optical elements. In addition, NCU has an excellent theoretical group in

                                                 47
condensed matter physics, who can provide valuable computational skills to the
analysis and development of nano-devices and nano-materials.


8.2 National Chiao Tung University

     National Chiao Tung University is best known for its programs in Electronics
and Information Sciences. It has the best semiconductor processing facility and the
computer facility in Taiwan. Many of our research programs support the
technologies being used in the Science Park. Indeed, most of the graduates from the
university join the companies in the Science Park. The close tie between the school
and the Science Park is similar to that between the Stanford University and the
companies of Silicon Valley. As one of the major research universities in Taiwan,
NCTU’s faculty body is internationally known for its research capability. Just in the
department of Electronics Engineering alone, there are eight IEEE fellows. NCTU
has an established Center for Nano Science and Technology. Our school center has
organized courses, seminars and workshops in the nanosciences. It has signed an
agreement with ITRI to design a program to train its engineers in nanotechnology.
NCTU has also recently established a “Tera Hertz Measurement Center” dedicated
to the semiconductor Tera Hertz program, which is an important application of the
semiconductor nanotechnology. The school has allocated 14 million NT dollars for
the support of this center. The semiconductor research center in Chiao Tung
University and the NSC’s Nano Device Lab. will provide state-of-the-art processing
capabilities for device fabrication.


8.3 National Tsing Hua University

  National Tsing Hua University is rated as one of the best research and teaching
institutions in Taiwan. One distinctive feature is our emphasis on
developing balanced and distinguished programs in both science and
engineering. The span and depth in fundamental science and engineering practice is
the most profound among Taiwan universities. True to our heritage, NTHU has
consistently promoted innovative education. Our graduates are not only the most
highly prized by industry (as documented in recent polls), but to date most of the
Chinese Nobel Laureates are graduates of either NTHU or our counterpart in
mainland China. NTHU has a long tradition in material science and engineering,
in which a strong basis on theory and experiments inform every aspect of our
research and teaching programs. As a consequence, our materials preparation and
characterization facilities compare favorably with those at the best universities in the


                                           48
world. We have ten clean rooms distributed among different departments and
research centers on campus ( Material Science, Physics, Chemical Engineering,
Nuclear Science and Engineering, and Electrical Engineering). NTHU is equally
well equipped with the state-of-the-art instruments like SIMS, ESCA, NMR,
HRTEM, RBS, HREEL, fs-PL, etc. The first ion-implanter and ECR-CVD in
Taiwan were installed and developed at NTHU. NTHU also maintains very close
ties with ITRI since ITRI’s inception more than three decade ago. Academia Sinica
cooperates with NTHU in several joint research and teaching programs. NTHU
professors participated in and were in charge of the successful building of the
Hsinchu Synchrotron Accerator Facility. NTHU's Nanotechnology and MEMS
Center (NTMC) was the first nano Center to be installed at a Taiwan university;
eighty professors from different disciplines participate in its research and education
activities. The Engineering Building III was renovated to become the first building
in Taiwan to be devoted to MEMS and Nano Science. With the establishment of the
UST Nano Center, researchers at NTHU will have ample opportunity to cooperate
closely with our colleagues in the greater nano community of Taiwan.

8.4   National Yang Ming University


       National Yang Ming University is a biomedicine-based research university,
which will make strong contributions to the proposed bionanotechnology
investigations.     All of the proposed biological or medical research topics involve
the active interests of research groups at NYMU. The new technologies explored
in this program may profitably be compared with conventional methodologies to
verify the validity of the new techniques. From a complementary perspective, the
novel nanotechnology-based approaches highlighted in this proposal may also open
up new horizons for traditional biomedical investigations. The medical center of
NYMU provides a critical route for the assessment of potential clinical applications
of the results and products generated by this program.




9.0 Program assessment and program review

The operation of the center and the progress of its programs will be reviewed in a
regular basis. Proposals for new research directions, programs and management
adjustment will also be reviewed from time to time.



                                          49
A program review board consisting of members from the technical advisory board
will be formed to conduct the yearly review. The review will consist of two parts:
the center operation and the research programs. The function of the program review
board is shown in Fig. 9.1. For the center operation, the lab management, budget
control, personnel control, and capital equipment expenditure will be reviewed. The
center director and the management office will prepare an annual report with
detailed descriptions of the center operation for the review board. The executive
office will also submit the next year plan for the board to review. The review board
will put the suggestions and comments in writing and send it back to the center. The
center will then prepare the revised plan for final review and approval. The whole
review process should be conducted and finished within a month before the start of


                             Program review board




          Center operation                           Research programs


     1. lab management                            1. research progress
     2. budget control                            2. research directions
     3. personnel control                         3. international
     4. capital equipment                            collaborations
        expenditure                               4. local collaborations
     5. next year plan                            5. impact to industries



  Fig. 9.1 The function of the program review board.

each fiscal year.

The progress of the research programs will also be reviewed yearly by the program
review board. The principal investigator of each program will prepare a progress
report with detailed description on the achievement and progress attained. The
review board will decide whether to continue fund the program based on the report.
Proposals for new research programs will also be reviewed at this time. Each
program should have a three year plan. If funded, the allocated fund will be for three
years with a contingency of yearly approval by the review board. The decision on
the acceptance of the research projects will be based on (1) scientific significance, (2)
technological impact, (3) qualification of the research team.

                                           50
       The review process is shown in the flow chart of Fig. 9.2. It consists of (1) review of
       the reports, on-site visit, and (2) review meetings including technical presentations
       by the PIs. The suggestions, comments and any decisions on the research projects
       from the review board will be compiled and given to the center director to formulate
       the final yearly plan.


                                       Program review board




          Review and on-site visit                                     Technical meeting



Annual report             New year plan                  Research progress reports     New proposals



                                          Suggestions and
                                          comments




                                          Final yearly plan

                Fig. 9.2 The flow chart of the review process.



       The monitoring of the center operation and the research programs will be conducted
       by the steering committee, also consists of members from the advisory board. The
       members of the steering committee will pay monitoring visits to the center at least
       twice a year. The mission of the committee, besides monitoring, is to help the center
       director in program management and fine tuning the research directions.




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