Date of Award

12-2006

Document Type

Thesis

Degree Name

Master of Science in Material Science Engineering (MSMatSE)

Department

Materials Science

First Advisor

Dr. Mohamed Assaad Abdel-Raouf

Second Advisor

Dr. Noureddine Amrane

Third Advisor

Prof. Dr. Nacir Tit

Abstract

Group III nitrides are highly attractive materials because of their great potential for the development of optoelectronic devices in short wavelength, semiconductor lasers and optical light-emitters and detectors. GaN, AlN and InN are considered as the most important compounds in this class of materials. In this work, we present a theoretical investigation of the electronic properties (band structure, density of state and contour maps of the charge density distribution) and optical properties (refractive index, absorption and dielectric constants). Also, we investigate the band structures and optical properties of AlN/GaN and InN/GaN super lattices. A full-potential linearized plane-wave (FPLAPW) method is employed within the framework of the computer package WIEN2k. Comparisons between the properties of each system and those of its constituents are made. The values of the energy gaps of these compounds obtained by LDA differ significantly from the experimental values and generally agree more closely with other theoretical values. In addition, the charge densities have been presented and provide additional evidence for the similarity of the bonding of GaN, AlN and InN. Also, we have shown that the optical properties are excellently reproduced using LDA calculations, if we allow for a rigid shift of the band structure, namely using the so called scissors operator.

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