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

Abstract

Native vacancies in Te-doped (5×1016-5×1018cm-3)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-TeAs-donor complexes. These complexes are the dominating type of vacancy defects in the doping range under observation. © 1999 American Physical Society.