| Linearized Muffin-Tin Orbital (LMTO) calculations were performed to study the electronic structure and bonding of point defects in cubic (zinc-blende) BN (c-BN), AlN (c-AlN), and GaN (c-GaN), and for a highly strained AlN/BN superlattice. Anion and cation vacancies were studied in c-BN and c-GaN, as were various anion and cation substitutional impurities: Be and Mg in c-BN, Mg in c-AlN, and O, Zn and Cd in c-GaN.; Benchmark calculations were performed to verify the accuracy and optimize the efficiency of the calculations. Large outward relaxation was predicted for atoms neighboring vacancies and impurities in c-BN. Small outward relaxation was predicted near Mg impurities in c-AlN. Except for the Zn impurity in c-GaN, donor and acceptor bands tended to be moderately to highly localized near defect sites. Type II alignment was predicted for the relaxed (001) AlN/BN superlattice. AlN layers bore the greatest strain and exhibited the greatest band bending. |
