The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing
The GaBixAs1-x bismide III-V semiconductor system remains a relatively underexplored alloy particularly with regards to its detailed electronic band structure. Of particular importance to understanding the physics of this system is how the bandgap energy E-g and spin-orbit splitting energy Delta(o)...
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my.utm.338842018-11-30T06:39:09Z http://eprints.utm.my/id/eprint/33884/ The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing Batool, Z. Hild, K. Hosea, Thomas Jeffrey Cockburn Lu, X. Tiedje, T. Sweeney, S. J. Q Science The GaBixAs1-x bismide III-V semiconductor system remains a relatively underexplored alloy particularly with regards to its detailed electronic band structure. Of particular importance to understanding the physics of this system is how the bandgap energy E-g and spin-orbit splitting energy Delta(o) vary relative to one another as a function of Bi content, since in this alloy it becomes possible for Delta(o) to exceed Eg for higher Bi fractions, which occurrence would have important implications for minimising non-radiative Auger recombination losses in such structures. However, this situation had not so far been realised in this system. Here, we study a set of epitaxial layers of GaBixAs1-x (2.3% <= x <= 10.4%), of thickness 30-40 nm, grown compressively strained onto GaAs (100) substrates. Using room temperature photomodulated reflectance, we observe a reduction in E-g, together with an increase in Delta(o), with increasing Bi content. In these strained samples, it is found that the transition energy between the conduction and heavy-hole valence band edges is equal with that between the heavy-hole and spin-orbit split-off valence band edges at similar to 9.0 +/- 0.2% Bi. Furthermore, we observe that the strained valence band heavy-hole/light-hole splitting increases with Bi fraction at a rate of similar to 15 (+/- 1) meV/Bi%, from which we are able to deduce the shear deformation potential. By application of an iterative strain theory, we decouple the strain effects from our experimental measurements and deduce E-g and Delta(o) of free standing GaBiAs; we find that Delta(o) indeed does come into resonance with E-g at similar to 10.5 +/- 0.2% Bi. We also conclude that the conduction/valence band alignment of dilute-Bi GaBiAs on GaAs is most likely to be type-I. AIP Publishing 2012-06 Article PeerReviewed Batool, Z. and Hild, K. and Hosea, Thomas Jeffrey Cockburn and Lu, X. and Tiedje, T. and Sweeney, S. J. (2012) The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing. Journal of Applied Physics, 111 (11). pp. 1-7. ISSN 0021-8979 http://dx.doi.org/10.1063/1.4728028 DOI:10.1063/1.4728028 |
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Q Science Batool, Z. Hild, K. Hosea, Thomas Jeffrey Cockburn Lu, X. Tiedje, T. Sweeney, S. J. The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
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The GaBixAs1-x bismide III-V semiconductor system remains a relatively underexplored alloy particularly with regards to its detailed electronic band structure. Of particular importance to understanding the physics of this system is how the bandgap energy E-g and spin-orbit splitting energy Delta(o) vary relative to one another as a function of Bi content, since in this alloy it becomes possible for Delta(o) to exceed Eg for higher Bi fractions, which occurrence would have important implications for minimising non-radiative Auger recombination losses in such structures. However, this situation had not so far been realised in this system. Here, we study a set of epitaxial layers of GaBixAs1-x (2.3% <= x <= 10.4%), of thickness 30-40 nm, grown compressively strained onto GaAs (100) substrates. Using room temperature photomodulated reflectance, we observe a reduction in E-g, together with an increase in Delta(o), with increasing Bi content. In these strained samples, it is found that the transition energy between the conduction and heavy-hole valence band edges is equal with that between the heavy-hole and spin-orbit split-off valence band edges at similar to 9.0 +/- 0.2% Bi. Furthermore, we observe that the strained valence band heavy-hole/light-hole splitting increases with Bi fraction at a rate of similar to 15 (+/- 1) meV/Bi%, from which we are able to deduce the shear deformation potential. By application of an iterative strain theory, we decouple the strain effects from our experimental measurements and deduce E-g and Delta(o) of free standing GaBiAs; we find that Delta(o) indeed does come into resonance with E-g at similar to 10.5 +/- 0.2% Bi. We also conclude that the conduction/valence band alignment of dilute-Bi GaBiAs on GaAs is most likely to be type-I. |
format |
Article |
author |
Batool, Z. Hild, K. Hosea, Thomas Jeffrey Cockburn Lu, X. Tiedje, T. Sweeney, S. J. |
author_facet |
Batool, Z. Hild, K. Hosea, Thomas Jeffrey Cockburn Lu, X. Tiedje, T. Sweeney, S. J. |
author_sort |
Batool, Z. |
title |
The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
title_short |
The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
title_full |
The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
title_fullStr |
The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
title_full_unstemmed |
The electronic band structure of GaBiAs/GaAs layers: influence of strain and band anti-crossing |
title_sort |
electronic band structure of gabias/gaas layers: influence of strain and band anti-crossing |
publisher |
AIP Publishing |
publishDate |
2012 |
url |
http://eprints.utm.my/id/eprint/33884/ http://dx.doi.org/10.1063/1.4728028 |
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1643649459496681472 |
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13.160551 |