Energetics and kinetics of native point defects in Ga2Se3from first principles

Abstract

Based on first-principles calculations, the Ga vacancy and antisite defect Se${}_{\mathrm{Ga}}$ are the only intrinsic shallow acceptors in Ga${}_{2}$Se${}_{3}$. The Ga interstitial is always a donor, $+$3 charge state under $p$-type conditions or $+$1 charge state under $n$-type conditions. Both the Se vacancy and Se interstitial are neutral defects except under an extremely $p$-type condition. Both the Ga interstitial and Se interstitial are predicted to be a very fast diffuser under $n$-type conditions, with a migration barrier value of $<$0.3 eV. Under $p$-type conditions, the calculated migration barrier of the Ga interstitial has a quite large value of $>$1.0 eV. The $+$2 charge state is stable for the Se interstitial under the extremely $p$-type condition, and the corresponding migration barrier is 0.68 eV. The migration barriers of the Ga vacancy and Se vacancy are $>$0.8 eV and $>$1.3 eV, respectively.