Characterizing Native Point Defects in ZnO Bulk by Positron Annihilation Spectroscopy

Abstract

Positron annihilation spectroscopy was employed to study the native point defects in ZnO single crystal, in combination with calculated results of positron lifetime and electron momentum distribution. The theoretical and experimental results of the positron lifetime in ZnO bulk ensure the presence of zinc monovacancy, and zinc monovacancy concentration begins to decrease above 600oC annealing treatment. Oxygen vacancies have been characterized by coincidence Doppler broadening (CDB) spectroscopy, combined with calculated electron momentum distribution. CDB spectroscopies show that oxygen vacancies don't appear until 600oC annealing treatment, and increase due to ZnO decomposition with annealing temperature rising.