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Origin of the Large Bandgap Bowing in Highly Mismatched Semiconductor AlloysWe use a combination of optical and soft x-ray fluorescence techniques to investigate the composition dependence of the band edge energies in ZnSe(1-x)Te(x) and ZnS(1-x)Te(x) alloys. The results reveal entirely different origins of the large bandgap bowing for alloys with small and large Te content. On the Te-rich side, the reduction of the bandgap is well explained by the band anticrossing interaction between the Se or S localized states and the ZnTe conduction band states. On the Se or S-rich side, an interaction between the localized Te states and the degenerate GAMMA valence bands of ZnSe or ZnS is responsible for the bandgap reduction and the rapid increase of the spin-orbit splitting with increasing Te concentration. Results of soft x-ray fluorescence experiments provide direct evidence for the valence band anticrossing interaction. The bandgap bowing over the entire composition range is accounted for by a linear interpolation between the conduction band anticrossing and valence band anticrossing models.
Document ID
20020066653
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Wu, J.
(California Univ. Berkeley, CA United States)
Walukiewicz, W.
(California Univ., Lawrence Berkeley National Lab. Berkeley, CA United States)
Yu, K. M.
(California Univ., Lawrence Berkeley National Lab. Berkeley, CA United States)
Ager, J. W., III
(California Univ., Lawrence Berkeley National Lab. Berkeley, CA United States)
Haller, E. E.
(California Univ., Lawrence Berkeley National Lab. Berkeley, CA United States)
Miotkowski, I.
(Purdue Univ. West Lafayette, IN United States)
Ramdas, A. K.
(Purdue Univ. West Lafayette, IN United States)
Su, Ching-Hua
(NASA Marshall Space Flight Center Huntsville, AL United States)
Sou, I. K.
(Hong Kong Univ. of Science and Technology Clear Water Bay, Hong Kong)
Perera, R.
(California Univ., Lawrence Berkeley National Lab. Berkeley, CA United States)
Curreri, Peter A.
Date Acquired
August 20, 2013
Publication Date
January 1, 2002
Subject Category
Metals And Metallic Materials
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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