Photoluminescence line shape analysis of highly n‐type doped zincblende GaN

Abstract

An investigation of different n-type doped zincblende gallium nitride thin films measured by photoluminescence from 7 K to room temperature is presented. The spectra change with increasing free-carrier concentration due to many-body effects such as the Burstein–Moss shift and band-gap renormalization. The samples are grown by molecular beam epitaxy on a 3C-SiC/Si (001) substrate, and a free-carrier concentration above 1020 cm 3 is achieved by introducing germanium as a donor. The analysis of the measured spectra by a line-shape fit yields different transition processes for different doping concentrations and temperatures, such as a band–band transition and a band–acceptor transition. The conduction band dispersion of Kane’s model is perfectly suited to explain the experimental data quantitatively.