Absolute surface energies of semipolar planes of AlN during metalorganic vapor phase epitaxy growth

Abstract

We propose a new approach for calculating absolute surface energies of semipolar planes of AlN under metalorganic vapor phase epitaxy (MOVPE) growth conditions. The calculations using wedge-shape geometries demonstrate that the stable surface orientation depends on Al chemical potential. The calculated absolute surface energies of semipolar AlN112¯2 and 11¯01 are lower than that of N-polar AlN0001¯ surface under Al-rich condition. On the other hand, the surface energy of N-polar AlN0001¯ is lower than those semipolar surfaces under N-rich condition. The results on the orientation dependence of surface stability could provide valuable insights for the epitaxial growth conditions of AlN along semipolar orientations during the MOVPE growth.