The electronic band structure of GaBiAs/GaAs layers: Influence of strain and band anti-crossing
Batool, Z, Hild, K, Hosea, TJC, Lu, X, Tiedje, T and Sweeney, SJ (2012) The electronic band structure of GaBiAs/GaAs layers: Influence of strain and band anti-crossing JOURNAL OF APPLIED PHYSICS, 111 (11). ? - ?. ISSN 0021-8979
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The GaBi As 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 and spin-orbit splitting energy Δ vary relative to one another as a function of Bi content, since in this alloy it becomes possible for Δ to exceed E 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 GaBi As (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 , together with an increase in Δ , 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 ∼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 ∼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 and Δ of free standing GaBiAs; we find that Δ indeed does come into resonance with E at ∼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.
Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in Journal of Applied Physics 111 (11) 113108 and may be found at Z. Batool et al., JAP 111, 113108 (2012)
|Uncontrolled Keywords:||Science & Technology, Physical Sciences, Physics, Applied, Physics, MOLECULAR-BEAM EPITAXY, MODULATION SPECTROSCOPY, GAAS1-XBIX, PHOTOREFLECTANCE, SEMICONDUCTORS, TEMPERATURE, DEPENDENCE, GAP|
|Divisions:||Faculty of Engineering and Physical Sciences > Electronic Engineering > Advanced Technology Institute > Photonics|
|Depositing User:||Symplectic Elements|
|Date Deposited:||11 Oct 2012 09:57|
|Last Modified:||23 Sep 2013 19:43|
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