title: Vacancy defects as compensating centers in Mg-doped GaN.
abstract: We apply positron annihilation spectroscopy to identify V(N)-Mg(Ga) complexes as native defects in Mg-doped GaN. These defects dissociate in postgrowth annealings at 500-800 degrees C. We conclude that V(N)-Mg(Ga) complexes contribute to the electrical compensation of Mg as well as the activation of p-type conductivity in the annealing. The observation of V(N)-Mg(Ga) complexes confirms that vacancy defects in either the N or Ga sublattice are abundant in GaN at any position of the Fermi level during growth, as predicted previously by theoretical calculations.
authors.affiliation: Laboratory of Physics, Helsinki University of Technology, FIN-02150 Espoo, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Hautakangas
authors.forename: J
authors.initials: J
authors.lastname: Oila
authors.forename: M
authors.initials: M
authors.lastname: Alatalo
authors.forename: K
authors.initials: K
authors.lastname: Saarinen
authors.forename: L
authors.initials: L
authors.lastname: Liszkay
authors.forename: D
authors.initials: D
authors.lastname: Seghier
authors.forename: H P
authors.initials: HP
authors.lastname: Gislason