Strain effect on band structure of InAlAs digital alloy

J. Zheng, Y. Tan, Y. Yuan, A. W. Ghosh and J. C. Campbell, Journal of Applied Physics , 125 (8) :082514 (2019).
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Recently, InAlAs digital alloys have been shown to exhibit unique electronic dispersion properties, which can be used to make low-noise avalanche photodiodes. In this paper, the strain effect is analyzed for its impact on the band structure of the InAlAs digital alloy. Simulation using a tight binding model that includes the strain effect yields bandgap energies that are consistent with experimental results. The bandgap would be larger without strain. In addition, a positive relationship has been found between minigaps of the InAlAs digital alloy and the band offset between bulk InAs and AlAs at the same position in k-space.