ABSTRACT
GaN and related compounds have been of great interest due to the development of applications such as high brightness light-emitting diodes and laser diodes operating in the blue/green to ultraviolet range. Relatively less information has been reported about the growth mechanisms of GaN on sapphire. In the late eighties, one of the major breakthroughs was the use of a low temperature nucleation layer to initiate the growth of the GaN active layers. The growth of high quality GaN is the major research topic for the fabrication of commercial devices such as light emitting diodes, lasers and high power electronic devices. The already numerous reports have shown that GaN grows along the c axis on top of the surface which exhibits a p2 symmetry. GaN layers contain a high density of defects such as inversion domains and stacking faults.
