Published online by Cambridge University Press: 15 March 2011
We report on high quality GaN layers grown with the use of one intermediate layer. The defect analysis shows that the density of dislocation is only 8×107/cm2 in these layers, compared to over 1010/cm2 for layers grown without the intermediate layer (IL). Electron microscopy on cross-section samples shows that deposition under certain specific conditions of a low- temperature IL directly benefits the quality of the subsequently deposited GaN layer. The growth of the GaN top layer appears to be similar to growth observed for lateral epitaxial overgrowth layers. This first time observation opens the possibility for using standard growth methods of GaN compounds to achieve a dislocation density comparable to that achieved with lateral overgrowth epitaxy.