In situ scanning tunnelling microscopic observations of the initial growth process of GaN in molecular-beam epitaxy revealed important differences between the growth on vicinal and flat SiC(00•1) substrates. On the basis of stop-growth scanning tunnelling microscopic studies, it was explained why there were orders-of-magnitude reductions in the densities of threading screw dislocations in the vicinal films. It was shown that, on vicinal surfaces, 3-dimensional islands developed into a characteristic shape. The islands coalesced much sooner than they did on flat surfaces. Fewer defects were therefore created at their boundaries.

Initial Stage of GaN Growth and its Implication to Defect Formation in Films. S.H.Cheung, L.X.Zheng, M.H.Xie, S.Y.Tong, N.Ohtani: Physical Review B, 2001, 64[3], 033304 (4pp)