Radiative capture rates at deep defects from electronic structure calculations

TL;DR

This paper introduces a first-principles methodology using hybrid density functional theory to accurately calculate radiative carrier capture rates at deep defects in semiconductors, validated against experimental data.

Contribution

It presents a novel computational approach for determining radiative capture coefficients at deep defects, enhancing the accuracy of defect modeling in semiconductors from electronic structure calculations.

Findings

Good agreement with experimental capture coefficients for GaAs and GaN defects.

Validation of the Condon approximation even with large lattice relaxations.

Demonstration of the method's accuracy in predicting defect-related radiative processes.

Abstract

We present a methodology to calculate radiative carrier capture coefficients at deep defects in semiconductors and insulators from first principles. Electronic structure and lattice relaxations are accurately described with hybrid density functional theory. Calculations of capture coefficients provide an additional validation of the accuracy of these functionals in dealing with localized defect states. We also discuss the validity of the Condon approximation, showing that even in the event of large lattice relaxations the approximation is accurate. We test the method on GaAs:$V_\text{Ga}$-$\text{Te}_\text{As}$ and GaN:C$_\text{N}$, for which reliable experiments are available, and demonstrate very good agreement with measured capture coefficients.