Speaker: Yazeed Alaskar
Affiliation: Ph.D. Candidate - UCLA
Abstract: Integration of arsenide based III-V compound semiconductors on silicon (Si) has been the focus of significant research to integrate light sources on silicon. This is to enable an integrated optical solution for chip-chip interconnects in future computing systems and to make cost-effective and efficient multi-junction solar cells on silicon substrates. The primary obstacle to success is the lattice and thermal expansion mismatches between semiconductor compounds of interest and the silicon substrates.
In this talk, a novel heteroepitaxial growth technique, quasi van der Waals epitaxy, promises the ability to grow high quality As based compounds on silicon using two-dimensional (2D) layered materials as a buffer layer, where the van der Waals forces is dominant between the layers making the restrains of lattice and thermal expantion coeffecnt mismatches to be less dominant. The talk is structured into three parts. First, theoretical investigations of quasi van der Waals heteroepitaxial growth of arsenide based III-V compounds on layered materials, such as graphene, Indium Selenide (InSe), Boron Nitride (h-BN) and Molybdenum Selenide (MoS2), where the surface free energy and adsorption energies of Ga, Al, In and As is calculated using DFT calculations. Second, experimental demonstration of a novel low temperature technique for quasi van der Waals heteroepitaxial growth of arsenide based III-V compounds on graphene using Molecular Beam Epitaxy (MBE) will be presented. Third, using Indium Selenide as a buffer layer, high quality and defect-free InGaAs/GaAs double heterostrucure (DH) is integrated onto GaAs/ Si structure. The crystal quality of GaAs shows the lowest defect density of GaAs grown directly on Si up to date, making it a remarkable step in obtaining optical emiters on Silicon substatres. The optical properties of this heterostructure is characterized using micro photoluminescence (μ-PL) demonstrating room-temperature light emission out of InGaAs/GaAs heterostructure integrated on thin GaAs on InSe/Si.
Biography: Yazeed Alaskar is a PhD candidate at the Department of Electrical Engineering, University of California- Los Angeles (UCLA). He received his bachelor degree of science from King Saud University in 2006, and his master degree from University of Michigan-Ann Arbor in 2011, both in electrical engineering. He joined Device Research Laboratory (DRL) in September 2011 as graduate student researcher under the supervision of Prof. Kang L. Wang. Nowadays, his current research interests include quasi van der Waals Epitaxial growth of III/V semiconductors on layered materials. Also, his research interests involve Molecular Beam Epitaxy (MBE), optoelectronic devices and solar cells. He has authored and co-authored over 7 journal articles, conference proceedings in the field of heteroepitaxial integration of III-V semiconductors.
Date(s) - Nov 10, 2016
10:00 am - 12:00 pm
E-IV Tesla Room #53-125
420 Westwood Plaza - 5th Flr., Los Angeles CA 90095