Epitaxial films were grown onto c-cut sapphire substrates by means of pulsed KrF laser deposition. The properties of the films were improved by increasing the growth temperature to 800C, and the N pressure during growth to 10mTorr. The room-temperature photoluminescence exhibited a strong band-edge emission at 3.4eV. Transmission electron microscopy revealed that the predominant defects were stacking faults which were parallel to the interface, and screw dislocations oriented along the c-axis. This contrasted with previous results in which most of the threading dislocations had been of edge type, with a Burgers vector of 1/3<11•0>.

Optical and Structural Properties of Epitaxial GaN Films Grown by Pulsed Laser Deposition T.F.Huang, A.Marshall, S.Spruytte, J.S.Harris: Journal of Crystal Growth, 1999, 200[3-4], 362-7