TRANSPARENT TRANSISTORS Transparent electronics is a nascent technology involving the realization of invisible electronic circuits . Birth of transparent electronics appears to coincide with announcement of p-type transparent electrical conductor CuAlO2 .The availability of such p-type material, in conjunction with conventional transparent n-type transparent electrical conductor such as ZnO, In2O3 makes feasible construction of pn junction. The realization of mechanically flexible, optically transparent light weight thin film transparent transistor and circuit is essential for development of new generation electronic devices.
WELCOME 1 Outline Introduction Manufacturing methods Types of TTFT Applications Conclusions Reference 3 Transparent electronics is a nascent technology involving the realization of invisible electronic circuits . Birth of transparent electronics appears to coincide with announcement of p-type transparent electrical conductor CuAlO2 .The availability of such p-type material, in conjunction with conventional transparent n-type transparent electrical conductor such as ZnO, In2O3 makes feasible construction of pn junction. The realization of mechanically flexible, optically transparent light weight thin film transparent transistor and circuit is essential for development of new generation electronic devices. Methods of manufacturing Spin coating sputtering 5 Spin coating Deposition of the coating fluid onto the wafer or substrate Acceleration of the substrate up to its final, desired, rotation speed Spinning of the substrate at a constant rate; fluid viscous forces dominate the fluid thinning behavior Spinning of the substrate at a constant rate; solvent evaporation dominates the coating thinning behavior 6 Sputtering Sputter deposition is a method of depositing thin films by sputtering Eroding, material from a "target," which then deposits onto a "substrate Sputtered atoms ejected into the gas phase are not in their thermodynamic equilibrium state, and tend to deposit on all surfaces in the vacuum chamber 7 Sputtering 8 General structure 9 Parameters Modulation r atio (Ion/Ioff ). Threshold voltage (Vt). Operating voltage. 10 Types Metal oxide thin film transistors Metal oxide nano wire semiconductor transistors Organic semiconductor transistor 11 Metal oxide TTFT Structure 12 Metal oxide semiconductor transistor Operates as n channel enhancement mode device Channel conductivity increases with + ve gate voltage VGS and VDS are in the range of 0-40v Magnitude of operating voltage and threshold voltages are directly proportional to gate insulator thickness. Drain current is depends on width to length ratio The average optical transmission in visible region of electromagnetic spectrum is around 75 percent 13 Forward characteristics Vds and Vgs are in the range of 0 to 40V ID is in the range of micro ampere Conductivity of the channel increases with increases with increase in gate voltage Threshold voltage is around 10-20 v 14 Drain current to drain voltage characteristics 15 Transfer characteristics and gate leakage current for a TTFT with a width-to-length ratio of 10:1 for VDS=10 V 16 Optical transmission spectra for entire structure 17 Optical char these spectra portray the raw transmission through the entire structure ZnO and ITO thickness for these device are 100&300nm Average optical transmission of visible region of electro magnetic spectrum is 75% Reduction in transmission light intensity is around 17% 18 Metal oxide thin film semiconductor transistor Transparent/flexible TFTs reported here are based on high-quality In2O3 semiconducting channel material doped/highly conducting In203 contacts, and a CPB gate dielectric on Melinex PET substrates The dielectric material is a cross linked polymer blend (CPB) film fabricated by spin-coating a mixture of polyvinylphenole (PVP) and a silane cross linker 19 Cross section of metal oxide semi conductor TTFT 20 Optical chara of metal oxide semiconductor TTFT 21 Metal oxide nanowire semiconductor transistor high performance transparent nanowire transistors (NWTs) individual In2O3nanowires as channels a multilayer self-assembled organic nano-dielec as the gate insulator NWTs use an individually addressable indium zinc oxide(IZO) or indium tin oxide (TO) bottom-gate Al as source/drain electrodes 22 Metal oxide nano wire transistor 23 Chara of metal oxide NWT 24 Optical chara 25 Organic semi conductor TTFT Top-contact bottom-gate transparent channel flexible n type OFETs were fabricated with NDI-8CN2 to demonstrate the unique materials properties. Thin NDI-8CN2 films (50 nm) were vapour-deposited onto acetate overhead transparency film coated with a spin-cast PEDOT:PSS polymeric gate P-UV polymer dielectric as gate insulator 26 Structure of organic TTFT 27 Chara of Organic TTFT 28 Optical Chara of Organic TTFT 29 Applications Wind shield display Solar cell Flat display LCD Printers Gas sensors 30 conclusions With the coming of transparent transistor entire semiconductor field undergo rapid change. Electronic goods will become so cheap and forming use and through. Since made on flexible substrate material will be flexible and thus causing to folded kept in pocket and handling become easy. The present thin film technology will be replaced by the transparent transistor thus causing better crystal display that too as cheep coast. 31 References Transparent transistors new class of semiconductors makes for fast , flexible, and invisible electronics By Boyd ,J,; Moore, S. K.; This paper appears in: Spectrum, IEEE Publication Date:2005 Volume:42,Issue:3 ZnO-based transparent thin-film transistors-R.L. Hoffman and B J Norris,December 2002 Transparent thin film transistors with Zinc iridium oxide channel layer;N.L.Dehull and E.S.kettenring; Journal in Applied physics December. H. Yanagi, K. Ueda, H. Ohta, M. Orita, M. Hirano, and H. Hosono, SolidState Commun. 121, 15 ~2001 H. Ohta, K. Kawamura, M. Orita, M. Hirano, N. Sarukura, and H, ! Hosono, Appl. Phys. Lett. 77, 475 ~2000 32 THANK YOU 33
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