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Proceedings Paper

Subband-dispersion and subband-mixing effects on excitonic spectra in thin-barrier superlattices
Author(s): Jin-Joo Song; John M. Jacob; Jin Fu Zhou; S. J. Hwang; Pan-Sang Jung; Yia-Chung Chang; Charles W. Tu
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Paper Abstract

Excitonic effects associated with subband dispersion and subband mixing have been investigated using photoluminescence excitation spectroscopy at liquid helium temperatures. A wide energy range has been studied in high quality AlGa1As/GaAs superlattices (SL's) by tunable cw dye lasers. Series of SL's grown by molecular beam epitaxy (MBE) have been designed with constant well widths and aluminum concentrations while the barrier widths (Lb's) vary. Each SL series has been carefully designed to produce a broad range of subband dispersion. We have observed significant changes in the excitonic spectra of the n=1 heavy hole (1HH), light hole (1LH), and n=2 heavy hole (2HH), as the Lb's vary. In particular, a wealth of excitonic peaks and structures were observed in the vicinity of the 2HH excitons within a certain range of Lb's in our SL samples. These arise from band mixing between 1LH and 2HH in conjunction with subband-dispersion associated excitonic effects. The observed lineshapes were compared with computer generated curves based on a comprehensive exciton theory. We also report observations of pronounced line narrowing effects in a SL. The linewidths of the 1HH and 1LH exciton peaks decrease significantly as the Lb's decrease. This narrowing can be explained with a theory which incorporates combined effects of well-to-well coupling and layer width irregularities.

Paper Details

Date Published: 1 October 1990
PDF: 9 pages
Proc. SPIE 1283, Quantum Well and Superlattice Physics III, (1 October 1990); doi: 10.1117/12.20762
Show Author Affiliations
Jin-Joo Song, Oklahoma State Univ. (United States)
John M. Jacob, Oklahoma State Univ. (United States)
Jin Fu Zhou, Oklahoma State Univ. (United States)
S. J. Hwang, Oklahoma State Univ. (United States)
Pan-Sang Jung, Oklahoma State Univ. (United States)
Yia-Chung Chang, Univ. of Illinois/Urbana-Champaign (United States)
Charles W. Tu, Univ. of California/San Diego (United States)

Published in SPIE Proceedings Vol. 1283:
Quantum Well and Superlattice Physics III
Gottfried H. Doehler; Emil S. Koteles; Joel N. Schulman, Editor(s)

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