Acceptor Binding Energies in GaN and AIN

Abstract

AbstractWe present binding energy calculations for Mg, Zn, and C substitutional shallow acceptors in GaN and AIN for both, wurtzite (WZ) and zincblende (ZB) crystal phases. The calculations are performed within the effective mass theory through the 6 × 6 Rashba-Sheka-Pikus and the Luttinger- Kohn matrix Hamiltonians for WZ and ZB bulk crystals, respectively. An analytic representation for the pseudopotential is used to introduce the nature of the impurity atom. The energy shift due to polaron effects is also considered in this approach. The estimated ionization energies are in good agreement with those reported experimentally and those reported theoretically employing other methods. We find that the binding energies for ZB GaN acceptors are shallower than the corresponding impurities in the WZ crystalline phase. The binding energy dependence upon the crystal field splitting in the WZ compounds is analyzed.