Computational studies on gan surface polarity and InN/GaN heterostructures by density functional theory and molecular dynamics

We have performed periodic density functional calculations and molecular dynamics (MD) simulations to investigate the reconstructions of the GaN (0001) surface and the heteroepitaxial growth process of InN thin films on the GaN surface. Grown GaN planes have a polar configuration. Surface energy calculations predict that the reconstruction of the N-terminated GaN (0001) surface is energetically more favorable than that of the Ga-terminated surface. MD results suggest that the growth of InN thin films on Ga- and N-terminated surfaces is different. On the N-terminated surface, the surface morphology of the grown InN layer is three-dimensional and rough. On the other hand, on the Ga-terminated surface, it is observed that the InN molecules have adequate migration mobility for growth and this suggests that the growth follows the two-dimensional growth mode.