Experimental and theoretical studies of band gap alignment in GaAs1−xBix/GaAs quantum wells

Band gap alignment in GaAs1−xBix/GaAs quantum wells (QWs) was studied experimentally by photoreflectance (PR) and theoretically, ab initio, within the density functional theory in which the supercell based calculations are combined with the alchemical mixing approximation applied to a single atom in...

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Bibliographic Details
Published in:Journal of applied physics 2014-12, Vol.116 (23)
Main Authors: Kudrawiec, R., Kopaczek, J., Polak, M. P., Scharoch, P., Gladysiewicz, M., Misiewicz, J., Richards, R. D., Bastiman, F., David, J. P. R.
Format: Article
Language:English
Subjects:
Alignment
Applied physics
Conduction bands
Density functional theory
Energy gap
Gallium arsenide
Low concentrations
Mathematical analysis
Quantum confinement
Quantum wells
Reduction
Valence band
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Summary:Band gap alignment in GaAs1−xBix/GaAs quantum wells (QWs) was studied experimentally by photoreflectance (PR) and theoretically, ab initio, within the density functional theory in which the supercell based calculations are combined with the alchemical mixing approximation applied to a single atom in a supercell. In PR spectra, the optical transitions related to the excited states in the QW (i.e., the transition between the second heavy-hole and the second electron subband) were clearly observed in addition to the ground state QW transition and the GaAs barrier transition. This observation is clear experimental evidence that this is a type I QW with a deep quantum confinement in the conduction and valence bands. From the comparison of PR data with calculations of optical transitions in GaAs1−xBix/GaAs QW performed for various band gap alignments, the best agreement between experimental data and theoretical calculations has been found for the valence band offset of 52 ± 5%. A very similar valence band offset was obtained from ab initio calculations. These calculations show that the incorporation of Bi atoms into GaAs host modifies both the conduction and the valence band. For GaAs1−xBix with 0 
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4904740