1 October 1990 Subband-dispersion and subband-mixing effects on excitonic spectra in thin-barrier superlattices
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Proceedings Volume 1283, Quantum Well and Superlattice Physics III; (1990) https://doi.org/10.1117/12.20762
Event: Advances in Semiconductors and Superconductors: Physics Toward Devices Applications, 1990, San Diego, CA, United States
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.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jin-Joo Song, John M. Jacob, Jin Fu Zhou, S. J. Hwang, Pan-Sang Jung, Yia-Chung Chang, and Charles W. Tu "Subband-dispersion and subband-mixing effects on excitonic spectra in thin-barrier superlattices", Proc. SPIE 1283, Quantum Well and Superlattice Physics III, (1 October 1990); doi: 10.1117/12.20762; https://doi.org/10.1117/12.20762

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