Ab initio calculation for the decomposition process of GaN (0001) and (000(1)over-bar) surfaces

The activation energies for Ga and N desorption from a GaN surface were calculated using the density functional theory to understand the decomposition process of the GaN(0 0 0 1) and (0 0 0 (1) over bar) Ga- and N-terminated surfaces under a hydrogen atmosphere. It was found that the Ga atoms on the GaN(0 0 0 1) Ga and (0 0 0 (1) over bar) Ga surfaces desorbed as GaH molecules from the surface and the Ga desorption energy for a GaN(0 0 0 1) surface was smaller than that for a GaN(0 0 0 1) surface. In the case of N-terminated surfaces, the N atoms on the GaN(0 0 0 (1) over bar) N and (0 0 0 1) N surfaces desorbed as NH3 molecules from the surface and the N desorption energy for a GaN(0 0 0 1) surface was smaller than that for a GaN(0 0 0 (1) over bar) surface. (C) 2007 Elsevier B.V. All rights reserved.