Identification of the arsenic vacancy defect in electron-irradiated GaAs

Abstract

We report the systematic observation of a new electron-paramagnetic-resonance spectrum in a wide series of electron-irradiated GaAs crystals. The spectrum consists of a partially resolved multiplet of 700-G linewidth and an effective g factor of 2.00 for B\ensuremath{\parallel}[001] and 2.04 for B\ensuremath{\parallel}[110]. Comparison of its production behavior, photoexcitation spectrum, observability up to T=70 K and its thermal annealing at T=500 K with previous results obtained by capacitance spectroscopy, lead us to attribute it to the arsenic vacancy perturbed by a distribution of arsenic interstitials (${V}_{\mathrm{As}{}^{\mathrm{\ensuremath{-}}}}$-${\mathrm{As}}_{\mathrm{i}}$). The experimental spectrum is well simulated in this model with the spin-Hamiltonian parameters S=1, ${g}_{?}$(${V}_{\mathrm{As}}$-${\mathrm{As}}_{\mathrm{i}}$)=2.00, ${g}_{\ensuremath{\perp}}$(${V}_{\mathrm{As}}$-${\mathrm{As}}_{\mathrm{i}}$)=2.02 and D=0.4 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$.