Date of Award

3-1999

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

David E. Weeks, PhD

Abstract

The focus of this research is an investigation of energy band anisotropy in simple quantum well structures. This anisotropy results from the asymmetry of the periodic potential within the crystal lattice. For sufficiently high doping levels, band structure anisotropy is expected to play an important role in the evaluation of the electronic and optical properties of the quantum well structures. The analysis uses a model based on a 6x6 Luttinger-Kohn k.p approach for bulk material valence band structure together with the Envelope Function Approximation. The model is used to analyze Si/SiGe, AlGaAs/GaAs, and GaAs/InGaAs quantum wells for the 001 and the 110 growth directions. The resulting band structures show significant anisotropy for materials grown in both the 110 and 001 directions. In all cases the materials grown in the 110 direction show a more pronounced anisotropy than the materials grown in the 001 directions. For the 001 growth directions, the band structures were effectively isotropic for values of k-parallel less than 0.4 inverse angstrom for Si/SiGe, 0.6 inverse angstrom for GaAs/AlGaAs, and 0.5 inverse angstrom for InGaAs/GaAs.

AFIT Designator

AFIT-GAP-ENP-99M-07

DTIC Accession Number

ADA361447

Comments

The author's Vita page is omitted.

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