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Full-Text Articles in Physical Sciences and Mathematics
Negative Band Gap Bowing In Epitaxial Inas/Gaas Alloys And Predicted Band Offsets Of The Strained Binaries And Alloys On Various Substrates, Gus L. W. Hart, Kwiseon Kim, Alex Zunger
Negative Band Gap Bowing In Epitaxial Inas/Gaas Alloys And Predicted Band Offsets Of The Strained Binaries And Alloys On Various Substrates, Gus L. W. Hart, Kwiseon Kim, Alex Zunger
Faculty Publications
We use pseudopotential theory to provide (1) the band offsets of strained GaAs and InAs on various substrates and (2) the energies Ev(x) of the valence and conduction bands of InxGa1-xAs alloy, as a function of composition. Results are presented for both the bulk alloy and for the alloy strained on InP or GaAs. We predict that while Ex(x) bows downward for relaxed bulk alloys, it bows upward for strained epitaxial alloys. The calculated alloy offsets are used to discuss electron and hole localization in this system.
Effect Of Ga Content On Defect States In Cuin1-XGaXSe2 Photovoltaic Devices, Jennifer T. Heath, J. David Cohen, William N. Shafarman, Dongxiang Liao, Angus Rockett
Effect Of Ga Content On Defect States In Cuin1-XGaXSe2 Photovoltaic Devices, Jennifer T. Heath, J. David Cohen, William N. Shafarman, Dongxiang Liao, Angus Rockett
Faculty Publications
Defects in the band gap of CuIn1-xGaxSe2 have been characterized using transient photocapacitance spectroscopy. The measured spectra clearly show response from a band of defects centered around 0.8 eV from the valence band edge as well as an exponential distribution of band tail states. Despite Ga contents ranging from Ga/(In+Ga)=0.0 to 0.8, the defect bandwidth and its position relative to the valence band remain constant. This defect band may act as an important recombination center, contributing to the decrease in device efficiency with increasing Ga content.