Temperature dependence of the band gap shrinkage due to electron-phonon interaction in undoped n-type GaN

TL;DR

This study investigates how temperature affects the band gap shrinkage in undoped n-type GaN due to electron-phonon interactions, using photoluminescence spectra and modeling to analyze spectral shifts and broadening.

Contribution

It introduces a semi-empirical model based on phonon dispersion that accurately fits experimental data on GaN's temperature-dependent band-edge shifts.

Findings

Semi-empirical model fits experimental data well

Electron-phonon coupling constants are quantified

Temperature influences band gap and emission linewidths

Abstract

The photoluminescence spectra of band-edge transitions in GaN is studied as a function of temperature. The parameters that describe the temperature dependence red-shift of the band-edge transition energy and the broadening of emission line are evaluated using different models. We find that the semi-empirical relation based on phonon-dispersion related spectral function leads to excellent fit to the experimental data. The exciton-phonon coupling constants are determined from the analysis of linewidth broadening.