VIEWS: 16 PAGES: 1 POSTED ON: 12/29/2011
Statement of Research Interests Dr.Ziad Yousef Abu Waar Recently, there has been a great deal of interest in the fabrication of the low- dimensional (nanostructures) semiconductors. Of particular interest are quantum dots and ring like nanostructures. The motivations that simulate research in this field are basically related to the possibility of using these materials for studying basic properties and employing new devices. Here is a summery of some of my past research experiences in this field. I have designed a photoluminescence system to study the optical properties of the fabricated nanostructure systems. I have used droplet epitaxy technique to present a study on the formation of Ga droplets on (100), (311)A and (511)A GaAs substrates in which both substrate temperature and the amount of Ga supplied effects on the droplet formation, shape, size and density for the three different surfaces have been investigated. It is important to understand the Ga droplet formation, because it is the key point of understanding the density, shape and size of the GaAs nanostructures. Also I have used droplet epitaxy, by means of molecular beam epitaxy, on GaAs (100) surfaces to study the evolution between GaAs/Al0.3Ga0.7As Single ring like and double ring like nanostructures. Various growth temperatures, As4 fluxes, and monolayer depositions are examined in order to observe how to change the ring structures. Also I have investigated the influence of the size of GaAs/ Al 0.3 Ga 0.7 As double ring like nanostructures on their optical properties. I have performed a study of photoluminescence from uncapped non-oxidized and oxidized InAs quantum dots on GaAs substrate as a function of the thickness of a GaAs capping layer. A photoluminescence system in ultra-high-vacuum that was coupled onto a molecular beam epitaxy chamber was used in order to avoid the oxidation of the quantum dots surface. We have presented a method to control lateral ordering of one and multilayered In0.4Ga0.6As quantum dots grown on (100), (311)B, and (511)B GaAs substrates using natural surface anisotropic for (100), surface steps on high index GaAs substrates and the arsenic background. I was able to fabricate self-organized InAs quantum rings using the Stranski- Krastanov growth mode, and investigate their electronic and optical properties. Although the big efforts spent in this field many low-dimensional systems and their properties still rather ambiguous and unsettled. In my Future research I am planning to use self-assembled growth methods, particularly Stranski-Krastanov and droplet epitaxy to fabricate and characterize new and unexplored nonstructural systems using materials from III-V compounds (GaAs, InAs, InGaAs, AlGaAs).
"Research Interests Statement of Research"