The electronic properties and optical gap of (Zn,Mg)(S,Se) wide-gap solid solutions are studied using ab initio techniques and starting from the previously determined atomistic structure of the alloy. Compositional disorder is shown to close the gap substantially with respect to the predictions of the virtual-crystal approximation. The bowing of the fundamental gap versus composition predicted by our calculations is in very good agreement with experiments available for the Zn(S,Se) pseudobinary alloy. At temperatures typical of molecular-beam epitaxy growth, the quaternary alloy displays a rather large amount of short-range order whose effect is to slightly but unmistakably open the gap. Our results agree well with recent experimental data for the quaternary alloy. (C) 1999 American Institute of Physics. [S0003-6951(99)02044-6].

Effects of disorder on the optical gap of (Zn,Mg)(S,Se) / Saitta, A. M.; de Gironcoli, S.; Baroni, S.. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 75:18(1999), pp. 2746-2748. [10.1063/1.125136]

Effects of disorder on the optical gap of (Zn,Mg)(S,Se)

de Gironcoli, S.;Baroni, S.
1999-01-01

Abstract

The electronic properties and optical gap of (Zn,Mg)(S,Se) wide-gap solid solutions are studied using ab initio techniques and starting from the previously determined atomistic structure of the alloy. Compositional disorder is shown to close the gap substantially with respect to the predictions of the virtual-crystal approximation. The bowing of the fundamental gap versus composition predicted by our calculations is in very good agreement with experiments available for the Zn(S,Se) pseudobinary alloy. At temperatures typical of molecular-beam epitaxy growth, the quaternary alloy displays a rather large amount of short-range order whose effect is to slightly but unmistakably open the gap. Our results agree well with recent experimental data for the quaternary alloy. (C) 1999 American Institute of Physics. [S0003-6951(99)02044-6].
1999
75
18
2746
2748
Saitta, A. M.; de Gironcoli, S.; Baroni, S.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/16428
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