Epitaxial films were grown onto c-cut sapphire substrates by using pulsed 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 showed that the predominant defects were stacking faults, parallel to the interface, and screw dislocations along the c-axis. The latter differed from previous observations, using other deposition techniques, where most of the threading dislocations had been of edge type; with 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