Thickness versus composition phase diagrams for growth modes were determined for these structures. From the diagrams, strain energies were calculated by considering the stress relaxation which was due to the introduction of misfit dislocations. The surface energy was deduced from the bonding enthalpy of nearest-neighbour bonds on the surface, and the interface energy was estimated by considering the effects of dangling bonds due to lattice misfit and the sudden transition of bonding species at the hetero-interface. Again from the phase diagrams, it was found that layer-by-layer growth, as in

the case of the Frank-van der Merwe mode, was very difficult to achieve during the epitaxial growth of GaInN on GaN; if the InN fraction was large. The Volmer-Weber mode predominated in the phase diagram for GaInN/GaN structures. The influence of an AlN buffer layer, having a higher surface energy, was studied by introducing such a layer between the GaInN layer and the GaN substrate. It was recalled that layer-by-layer growth was more easily obtained if misfit dislocations were introduced, and an AlN layer was used as a buffer.

Effects of Misfit Dislocations and AlN Buffer Layer on the GaInN/GaN Phase Diagram of the Growth Mode. K.Nakajima, T.Ujihara, S.Miyashita, G.Sazaki: Journal of Applied Physics, 2001, 89[1], 146-53