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Title:Computational modeling of transport and growth-related processes of novel gallium-v materials for temperature-resilient and high-power electronics
Author(s):Ismail, Fawad Hassan
Director of Research:Ravaioli, Umberto
Doctoral Committee Chair(s):Ravaioli, Umberto
Doctoral Committee Member(s):Schutt-Aine, Jose E; Lyding, Joseph W; Bayram, Can; Mohamed, Mohamed Y
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
high power
computational modeling
density functional theory
monte carlo
mesh adaptation
molecular dynamics
epitaxial growth
atomistic simulation
gibbs-duhem integration
liquid-vapor coexistence
machine learning
deep learning
Abstract:Recently, there has been significant interest in exploring the potential in novel Ga-V materials for temperature-resilient and power electronics applications. These materials are based on mature and well-studied semiconductors, like GaAs and GaN, and there is untapped potential in utilizing unconventional elements, like Bi and Yb, to be used as alloy constituents. The successful run of Moore’s law, spanning half a century, combined with the maturity of computational methods in micro and nanotechnology, provides us with exciting potential for using atomistic and multi-scale modeling and simulation. In this work, we utilize the power of computing machinery to explore the material, transport, and growth-related aspects of Ga-V derived materials. To this end, this work has two main thrusts: (1) Dilute Bi alloy of GaAs is a promising candidate for semiconducting applications involving temperature-resilience. Inclusion of even a small percentage of Bi results in significant band-gap reduction compared to that in pure GaAs, owing to the appearance of an impurity level just below the valence band edge. As a consequence, hole mobility is experimentally reported to drop. We carry out first-principles electronic structure calculations to observe this impurity level using the density functional theory approach to disordered systems. Furthermore, we investigate the reduction in hole mobility using full-band Monte Carlo charge transport simulations. (2) In addition, GaN has emerged as one of the leading candidates for next generation power electronics technology. Some of the challenges related to the realization of its full potential include high-quality and reliable growth. Related issues manifest, among others, in crystal structure defects, and low p-dopant incorporation and activation. We carry out first-principles investigation of the formation energetics of point defects as well as defect complexes, with and without the inclusion of Yb. From a numerical point of view, we investigate the challenge of simulating high-power electronic devices, involving sharp variations in electric fields over short distances, through the moving mesh adaptation technique. Incorporation of Mg in GaN during epitaxial growth is investigated by simulating modulation doping. Critical assessment of semi-empirical interaction models is carried out in reference to first-principles calculations, to assess the relevance of Ga-Ga interaction in the cohesion of GaN. Finally, liquid-vapor coexistence properties are determined for a range of available interaction models for Ga, to assess their feasibility for inclusion in GaN high temperature growth-related process simulation.
Issue Date:2020-05-06
Rights Information:Copyright 2020 Fawad Hassan Ismail
Date Available in IDEALS:2020-08-27
Date Deposited:2020-05

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