First-principles calculations were made of positron states and annihilation at vacancies and vacancy complexes in InN. Momentum distributions of annihilating electron-positron pairs in indium (VIn) and nitrogen vacancies (VN) as well as mixed vacancy clusters were calculated. Based on the modelled data the possibility of their experimental detection and distinction using positron annihilation spectroscopy was discussed. No localization of the positron density was found for isolated VN and VN clusters of up to 4VN. On the other hand, VIn and mixed vacancy clusters acted as efficient positron traps in InN. While the calculated momentum distributions for the divacancy and VIn were quite close, mixed vacancy clusters which contained one VIn and two or more VN showed well distinct spectra, that could be distinguished in suitable positron annihilation experiments.

Towards Experimental Identification of Vacancy Complexes in InN. C.Rauch, I.Makkonen, F.Tuomisto: Physica Status Solidi A, 2011, 208[7], 1548-50