Computational studies on GaN surface polarity and InN/GaN heterostructuresby density functional theory and molecular dynamics

We have performed periodic density functional calculations and molecular dy namics (MD) simulations to investigate the reconstructions of the GaN (0001 ) surface and the heteroepitaxial growth process of InN thin films on the G aN surface. Crown GaN planes have a polar configuration. Surface energy cal culations predict that the reconstruction of the N-terminated CaN (0001) su rface is energetically more favorable than that of the Ga-terminated surfac e. MD results suggest that the growth of InN thin films on Ga- and N-termin ated surfaces is different. On the N-terminated surface, the surface morpho logy of the grown InN layer is three-dimensional and rough. On the other ha nd, on the Ga-terminated surface, it is observed that the InN molecules hav e adequate migration mobility for growth and this suggests that the growth follows the two-dimensional growth mode.