Ordering-Induced Optical Transitions And Hole-Reversal In Si/Ge Short-Period (001) Superlattices

M. A. Gell

doi:10.1117/12.947314

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18 August 1988 Ordering-Induced Optical Transitions And Hole-Reversal In Si/Ge Short-Period (001) Superlattices

M. A. Gell

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Proceedings Volume 0943, Quantum Well and Superlattice Physics II; (1988) https://doi.org/10.1117/12.947314
Event: Advances in Semiconductors and Superconductors: Physics and Device Applications, 1988, Newport Beach, CA, United States

Abstract

Pearsall et al [Phys Rev Lett 58, 729 (1987)] have recently presented electroreflectance data on short-period Si/Ge (001) superlattices grown on (001) Si substrates. It is clear from the electroreflectance spectra, that structure exists which more than likely originates from the Si/Ge superlattices. In this paper, results of calculations based on empirical pseudopotentials with spin-orbit coupling are presented which demonstrate that the basic conjectures of Pearsall et al concerning the Si/Ge (4:4) superlattice are correct. New assignments are suggested for transitions which have been observed and predictions are made which can be used to test these assignments. The character of superlattice states close to the band edges are discussed in terms of their real-space charge density and their origin in wavevector space. In particular, a reversal of |mj| = 3/2 and |mj| I = 1/2 valence states with changing buffer layer composition is demonstrated in terms of the effects on subband energy levels, subband dispersions and polarisation-dependence of cross-gap transition probabilities.

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M. A. Gell "Ordering-Induced Optical Transitions And Hole-Reversal In Si/Ge Short-Period (001) Superlattices", Proc. SPIE 0943, Quantum Well and Superlattice Physics II, (18 August 1988); https://doi.org/10.1117/12.947314

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