Positron lifetimes in GaAs

Abstract

The suitability of the positron-lifetime technique to the study of native vacancies in GaAs is demonstrated. Significant variations in positron lifetime among a variety of as-grown GaAs single crystals were observed. The longest positron lifetime was found in undoped samples. Annealing in vacuum at 300–500 °C reduced the long-lifetime component. The results present strong evidence for the existence of Ga vacancies in the as-grown material.