Optical characterization of high-purity cubic GaN grown on GaAs (001) substrate by metalorganic chemical vapor deposition

The optical properties of cubic GaN films have been investigated in the tem perature range of 10-300 K. Five peaks were observed at 10 K. From the depe ndence of photoluminescence emissions on the temperature and excitation int ensity, we have assigned two of the five peaks (2.926 and 2.821 eV) to dono r-acceptor pair (DAP) transitions. Furthermore, these two peaks were found to be related to a common shallow donor involved in the peak position previ ously reported at 3.150 eV. The intensities of DAP transitions were much we aker than that of excitonic emission even at low temperature, indicating a relatively high purity of our samples. (C) 2000 American Institute of Physi cs. [S0003-6951(00)00921-9].