Vacancy defects in electron-irradiated ZnO studied by Doppler broadening of annihilation radiation

Abstract

Vacancy defects in ZnO induced by electron irradiation were characterized by the Doppler broadening of annihilation radiation measurements together with the local density approximation calculations. Zinc vacancies $({V}_{\mathrm{Zn}})$ are responsible for positron trapping in the as-irradiated state. These are annealed out below $200\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. The further annealing at $400\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ results in the formation of secondary defects attributed to the complexes composed of zinc vacancies and zinc antisites $({V}_{\mathrm{Zn}}\ensuremath{-}{\mathrm{Zn}}_{\mathrm{O}})$.