The effect of Si on the growth mode of GaN

In the growth of InGaN on a SiH4-exposed GaN surface, a change in the growth mode is observed for low SiH4 doses. To help explain this observation the potential energy surface of Ga and N adatoms on a GaN (0001) surface containing an isolated Si atom in the terminating layer was calculated using plane wave density functional theory. The surface Si atom decreases the diffusion barrier of Ga and N adatoms relative to the corresponding diffusion barriers on the ideal GaN (0001) surface. In addition, the adatorn binding energies were not significantly affected by the Si surface atom. It was therefore concluded that the observed transition in growth mode of GaN cannot be simply explained by the presence of isolated Si atoms on the GaN surface. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.