Impact of Disorder on the Optoelectronic Properties of GaNyAs1xyBix Alloys and Heterostructures

Muhammad Usman, Christopher A. Broderick, and Eoin P. O’Reilly
Phys. Rev. Applied 10, 044024 – Published 9 October 2018
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Abstract

We perform a systematic theoretical analysis of the nature and importance of alloy disorder effects on the electronic and optical properties of GaNyAs1xyBix alloys and quantum wells (QWs), using large-scale atomistic supercell electronic structure calculations based on the tight-binding method. Using ordered alloy supercell calculations, we also derive and parametrize an extended-basis 14-band kp Hamiltonian for GaNyAs1xyBix. Comparison of the results of these models highlights the role played by short-range alloy disorder—associated with substitutional nitrogen (N) and bismuth (Bi) incorporation—in determining the details of the electronic and optical properties. Systematic analysis of large alloy supercells reveals that the respective impacts of N and Bi on the band structure remain largely independent, a robust conclusion that we find to be valid even in the presence of significant alloy disorder where N and Bi atoms share common Ga nearest neighbors. Our calculations reveal that N- (Bi-)related alloy disorder strongly influences the conduction- (valence-)band edge states, leading in QWs to strong carrier localization, as well as inhomogeneous broadening and modification of the conventional selection rules for optical transitions. Our analysis provides detailed insight into key properties and trends in this unusual material system, and enables quantitative evaluation of the potential of GaNyAs1xyBix alloys for applications in photonic and photovoltaic devices.

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  • Received 12 January 2018
  • Revised 20 June 2018

DOI:https://doi.org/10.1103/PhysRevApplied.10.044024

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & TechnologyCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Muhammad Usman1,*, Christopher A. Broderick2,3, and Eoin P. O’Reilly2,4

  • 1School of Physics, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
  • 2Tyndall National Institute, Lee Maltings, Dyke Parade, Cork T12 R5CP, Ireland
  • 3Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB United Kingdom
  • 4Department of Physics, University College Cork, Cork T12 YN60, Ireland

  • *musman@unimelb.edu.au

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Vol. 10, Iss. 4 — October 2018

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