First-Principles Calculations of Luminescence Spectrum Line Shapes for Defects in Semiconductors: The Example of GaN and ZnO

TL;DR

This paper uses first-principles calculations to model the luminescence line shapes of defects in GaN and ZnO, demonstrating a simplified one-dimensional approach that aligns well with experimental data.

Contribution

It introduces a density functional theory-based method for accurately predicting defect luminescence spectra, simplifying multi-dimensional vibronic problems to an effective one-dimensional model.

Findings

Luminescence lineshapes match experimental results closely.

Effective parameters reveal trends for defect identification.

The approach simplifies complex vibronic calculations.

Abstract

We present a theoretical study of broadening of defect luminescence bands due to vibronic coupling. Numerical proof is provided for the commonly used assumption that a multi-dimensional vibrational problem can be mapped onto an effective one-dimensional configuration coordinate diagram. Our approach is implemented based on density functional theory with a hybrid functional, resulting in luminescence lineshapes for important defects in GaN and ZnO that show unprecedented agreement with experiment. We find clear trends concerning effective parameters that characterize luminescence bands of donor- and acceptor-type defects, thus facilitating their identification.