Exciton-related photoluminescence in homoepitaxial GaN of Ga and N polarities

Abstract

A photoluminescence (PL) study of GaN homoepitaxial layers grown by metal-organic chemical-vapor deposition demonstrates the high optical quality of N-face layers deposited on vicinal (0001) GaN substrates. In contrast to broad PL emission in exact (0001) layers, narrow-bound (0.9 meV) and free-(A and B) excitonic transitions are observed. By following the PL spectra as a function of temperature and excitation power, the main optical transitions in the Ga- and the misoriented N-face layers are found to be the same. Observed differences are related to the distinct creation of donor and acceptor states in the samples of different polarities. © 2000 American Institute of Physics.