A Simple Approach to Growth Mode of InN and InGaN Thin Films on GaN(0001) Substrate

Abstract

The growth of InN and InGaN thin films on GaN(0001) substrates are simply interpreted by using the macroscopic theory using free energy formula with the aid of empirical interatomic potential calculations as well as ab initio calculations. Our empirical interatomic potential calculations reveal that the system with 2D growth with misfit dislocation (2D-MD) is more stable than that with 2D coherent growth (2D-coherent) for InN films beyond 0.7 monolayers (ML), and the thickness for the stabilization of 2D-MD decreases with In composition. Moreover, the analysis of free energies demonstrate that 2D-MD is favored under In-rich conditions while three-dimensional growth with both islands and misfit dislocations is favored under N-rich conditions. The difference in growth mode is due to the surface energy anisotropy depending on the growth condition. The results suggest the surface energy anisotropy is a crucial factor for determining the growth modes of InN and InGaN on GaN(0001) substrate.