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Tuned and screened range-separated hybrid density functional theory for describing electronic and optical properties of defective gallium nitride

At a Glance

Section titled ā€œAt a Glanceā€
MetadataDetails
Publication Date2020-06-18
JournalPhysical Review Materials
AuthorsD. Kirk Lewis, Ashwin Ramasubramaniam, Sahar Sharifzadeh
InstitutionsBoston University, University of Massachusetts Amherst
Citations21

Abstract

Section titled ā€œAbstractā€

We apply a hybrid density functional theory approach, based on a tuned and screened range-separated hybrid (SRSH) exchange-correlation functional, to describe the optoelectronic properties of defective gallium nitride (GaN). SRSH and time-dependent SRSH (TDSRSH) are tuned to produce accurate energetics for the pristine material and applied to the study of a series of point defects in bulk GaN, a blue light-emitting material that degrades in the presence of defects. We first establish the accuracy of the method by comparing the predicted quasiparticle gap and low-energy excitation spectra of (TD)SRSH and many-body perturbation theory for both pristine GaN and GaN containing a single nitrogen vacancy. Aided by the reduced computational cost of (TD)SRSH, we then report on three additional technologically relevant point defects and defect complexes in GaN: the gallium vacancy, the carbon interstitial, and the carbon-silicon complex. We compute the low-energy optical absorption spectra for these defects and show the presence of defect-centered transitions. Furthermore, by estimating the Stokes shift, we predict, in agreement with previous studies, that the carbon substitutional defect is a candidate for the detrimental yellow luminescence in GaN. Furthermore, this study indicates that TDSRSH is a promising and computationally feasible approach for quantitatively accurate, first-principles modeling of defective semiconductors.

Tech Support

Section titled ā€œTech Supportā€

Original Source

Section titled ā€œOriginal Sourceā€

References

Section titled ā€œReferencesā€
  1. 2015 - The Physics of Semiconductors: An Introduction Including Nanophysics and Applications
  2. 1979 - Excitons

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