Microscopic identification of native donor Ga-vacancy complexes in Te-doped GaAs

Abstract

Native vacancies in Te-doped ${(5\ifmmode\times\else\texttimes\fi{}10}^{16}{--5\ifmmode\times\else\texttimes\fi{}10}^{18}{\mathrm{}\mathrm{cm}}^{\mathrm{\ensuremath{-}}3})\mathrm{ }\mathrm{GaAs}$ were investigated by means of positron lifetime and Doppler-broadening coincidence spectroscopy. The experimental data were related to theoretical calculations of the positron lifetime and the annihilation momentum distribution. Monovacancies were observed in all Te-doped GaAs samples under study. It will be shown that they can directly be identified to be Ga-vacancy--${\mathrm{Te}}_{\mathrm{As}}$-donor complexes. These complexes are the dominating type of vacancy defects in the doping range under observation.