Vacancy complexes in GaAs: Effects on impurity compensation.

Abstract

The energetics of shallow impurity compensation in GaAs via reactions of the type ${\mathit{V}}_{\mathrm{As}}$\ensuremath{\rightarrow}(${\mathit{V}}_{\mathrm{Ga}}$+${\mathrm{Ga}}_{\mathrm{As}}$), where V denotes a vacancy and ${\mathrm{Ga}}_{\mathrm{As}}$ a Ga-antisite defect is examined. It is proposed that in n-type GaAs this single-atom-displacement reaction is unstable with respect to a similar type of process, namely, 2${\mathit{V}}_{\mathrm{As}}$\ensuremath{\rightarrow}(${\mathit{V}}_{\mathrm{As}}$+${\mathit{V}}_{\mathrm{Ga}}$+GaAs). The latter does not lead to any compensation of donors, thereby removing discrepancies between theoretical predictions and experimental results on donor passivation by native defects in GaAs.