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Efficient ab initio plus analytic calculation of the effect of GaN layer tensile strain in AlGaN/GaN heterostructures

Date, Mihir and Mukherjee, Sudipta and Ghosh, Joydeep and Saha, Dipankar and Ganguly, Swaroop and Laha, Apurba and Ghosh, Prasenjit (2019) Efficient ab initio plus analytic calculation of the effect of GaN layer tensile strain in AlGaN/GaN heterostructures. In: JAPANESE JOURNAL OF APPLIED PHYSICS, 58 (9).

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Official URL: https://dx.doi.org/10.7567/1347-4065/ab39d0

Abstract

We have addressed the existing ambiguity regarding the effect of tensile strain in the underlying GaN layer on AlxGa1-xN/GaN heterostructure properties. The bandgaps and band-offsets for AlxGa1-xN on strained GaN were first computed using density functional theory (DFT), in the generalized gradient approximations (GGA) and hybrid functional Gaussian-Perdew-Burke-Ernzerhof (Gau-PBE) regimes. We propose a simple model to relate the GGA and Gau-PBE bandgaps, which is used to determine the realistic bandgaps of strained AlGaN. The bandgaps and band-offsets from the DFT calculations are then used to analytically calculate the two-dimensional electron gas density in an AlxGa1-xN/GaN hetero-interface. Our bandstructure calculations show that it is not possible to induce significant change in band-offsets through strain in the GaN layer. The charge-density calculations indicate that such strain can, however, modulate the polarization charge and thereby enhance the 2DEG density at the AlGaN/GaN interface substantially.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to IOP PUBLISHING LTD
Keywords: BAND-GAP; ALXGA1-XN; TEMPERATURE; DEPENDENCE; CONSTANTS
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Depositing User: Id for Latest eprints
Date Deposited: 20 Nov 2019 10:04
Last Modified: 20 Nov 2019 10:04
URI: http://eprints.iisc.ac.in/id/eprint/63589

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