Metalorganic vapor phase epitaxy growth and photoluminescence properties of cubic AlxGa1-xN

We have grown cubic AlxGa1-xN (0<x<0.25) films on GaAs (100) substrates by metalorganic vapor phase epitaxy. A strong excitonic transition, as well as a donor-acceptor pair transition and a deep-level emission, was observed in the photoluminescence spectra at 5 K in all the samples. With increasing Al fraction, all the emission lines shift to higher energy, nevertheless, with different shift rates. The temperature-dependent photoluminescence spectra show that the behavior of the donor-acceptor pair transition varied with Al fraction; at higher Al concentrations, the donor-acceptor pair transition tends to transform to a free-electron to acceptor transition and survive even at room temperature. This can also explain the energy shift to higher energy with increasing temperature for this emission line. (C) 1998 American Institute of Physics.