Dominating behaviour of the donor-acceptor pair emission in mass-transport GaN

A comprehensive study of the donor-acceptor pair (DAP) luminescence band in mass-transport grown GaN in wide ranges of temperature and excitation conditions was performed. Based on spatially resolved micro-photoluminescence, secondary ion mass spectroscopy, Raman scattering and positron annihilation spectroscopy results, as well as on a kinetic analysis of the emission intensities, we propose an acceptor like complex, creating a state as a semiclassical potential well near the valence band bottom due to the tensile strain caused by the empty clusters to be responsible for the dominating behaviour of the DAP emission.