Temperature dependent band gap shrinkage in GaN: Role of electron–phonon interaction

We present an experimental investigation of temperature dependent band-gap shrinkage in GaN using photoluminescence spectroscopy. The near-band-edge transition energy shifts to lower energy with increasing temperature. The parameters that describe the temperature-dependent red-shift of the band-edge transition energy are evaluated using different models. It has been found that the semi-empirical relation based on phonon-dispersion related spectral function leads to an excellent fit to the experimental data.