Strongly nonparabolic variation of the band gap in InxAl1-xN with low indium content
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Accepted version
Date
2015-12-14
Authors
Zubialevich, Vitaly Z.
Dinh, Duc V.
Alam, Shahab N.
Schulz, Stefan
O'Reilly, Eoin P.
Parbrook, Peter J.
Journal Title
Journal ISSN
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Publisher
IOP Publishing
Published Version
Abstract
80–120 nm thick InxAl1−xN epitaxial layers with 0 < x < 0.224 were grown by metalorganic vapour phase epitaxy on AlN/Al2O3-templates. The composition was varied through control of the growth temperature. The composition dependence of the band gap was estimated from the photoluminescence excitation absorption edge for 0 < x < 0.11 as the material with higher In content showed no luminescence under low excitation. A very rapid decrease in band gap was observed in this range, dropping down below 5.2 eV at x = 0.05, confirming previous theoretical work that used a band-anticrossing model to describe the strongly x-dependent bowing parameter, which in this case exceeds 25 eV in the x → 0 limit. A double absorption edge observed for InAlN with x < 0.01 was attributed to crystal-field splitting of the highest valence band states. Our results indicate also that the ordering of the valence bands is changed at much lower In contents than one would expect from linear interpolation of the valence band parameters. These findings on band gap bowing and valence band ordering are of direct relevance for the design of InAlN-containing optoelectronic devices.
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Keywords
InAlN , AlInN , band gap , band gap bowing parameter , photoluminescence excitation
Citation
Zubialevich, V. Z., Dinh, D. V., Alam, S. N., Schulz, S., O’Reilly, E. P. and Parbrook, P. J. (2015) 'Strongly nonparabolic variation of the band gap in InxAl1−xN with low indium content', Semiconductor Science and Technology, 31(2), 025006 (11 pp). doi: 10.1088/0268-1242/31/2/025006
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© 2016 IOP Publishing Ltd. This is the Accepted Manuscript version of an article accepted for publication in Semiconductor Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0268-1242/31/2/025006