Structures and Adsorption Behavior on N-Polar GaN(0001) Surface with Steps and Kinks: A DFT Study

Using density functional calculations, we systematically examine the adsorption characteristics of Ga and N atoms on stepped and kinked vicinal GaN(0001̅) surfaces under metal–organic vapor-phase epitaxy (MOVPE) growth conditions. The calculations reveal that surface reconstruction exerts a pronounced influence on the adsorption characteristics of Ga and N adatoms in the vicinity of step edges and kinks. In particular, we find that both Ga and N adatoms can be incorporated at kinks and step edges, in clear contrast to the behavior on conventional Ga-polar GaN(0001) surface. These findings provide valuable insights into the atomistic mechanisms governing the epitaxial growth of N-polar GaN, thereby advancing our understanding of the surface processes that determine crystal quality and morphology during the MOVPE growth.