Band gap and band parameters of InN and GaN from quasiparticle energy calculations based on exact-exchange density-functional theory

TL;DR

This study uses advanced quasiparticle calculations based on exact-exchange density-functional theory to accurately determine the electronic properties of InN and GaN, including band gaps and effective masses, aligning well with experimental data.

Contribution

It introduces a novel application of G0W0 calculations on exact-exchange DFT for InN and GaN, providing improved predictions of electronic properties and deriving parameters for k·p models.

Findings

Predicted InN band gap of 0.7 eV.

Good agreement with experimental blue shift due to Burstein-Moss effect.

Effective mass dependence on electron concentration matches recent experiments.

Abstract

We have studied the electronic structure of InN and GaN employing G0W0 calculations based on exact-exchange density-functional theory. For InN our approach predicts a gap of 0.7 eV. Taking the Burnstein-Moss effect into account, the increase of the apparent quasiparticle gap with increasing electron concentration is in good agreement with the observed blue shift of the experimental optical absorption edge. Moreover, the concentration dependence of the effective mass, which results from the non-parabolicity of the conduction band, agrees well with recent experimental findings. Based on the quasiparticle band structure the parameter set for a 4x4 kp Hamiltonian has been derived.