Density functional theory investigation of N interstitial migration in GaN

Using density-functional total energy calculations, we investigated N interstitial migration in GaN. Two migration paths were considered. The first path confines motion to a single c -plane of the lattice, while the second path involves movement both perpendicular and parallel to the c -axis. The latter path has a lower barrier for the positive charge states and will be the dominant mechanism for migration of the N interstitial in p -type GaN. The calculated barriers are 1.79, 2.12, and 1.98 eV for the +1, +2, and +3 charge states. These barriers are consistent with recent experimental results and indicate that interstitials will be mobile at typical processing temperatures. © 2006 American Institute of Physics.