Date of Award

12-1991

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Yung Kee Yeo, PhD

Second Advisor

Robert L. Hengehold, PhD

Abstract

Low temperature photoluminescence studies were performed on nine silicon germanium alloy superlattice samples. The luminescence spectra showed sharp peaks in the 0.95 to 1.05 eV energy range, and a broad band located 0.05 to 0.12 eV below the alloy bandgap. The sharp peaks were identified as transitions associated with impurity bound excitons. The linewidth was about 10 times that in pure silicon; in addition, the peaks shifted to lower energy as the sample temperature was raised from 1.4 to 15 K. These features were attributed to effects of random distribution of atoms in the alloy. The broad band shifted to lower energy as the temperature was raised and also narrowed considerably in bandwidth. This broad luminescence was attributed to recombination of excitons confined in potential wells created by local fluctuations in the alloy composition.

AFIT Designator

AFIT-GEP-ENP-91D-1

DTIC Accession Number

ADA243893

Comments

The author's Vita page is omitted.

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