Identification of the arsenic-antisite-arsenic-vacancy complex in electron-irradiated GaAs

We report the observation by electron paramagnetic resonance of a new irradiation-induced defect in n-type GaAs. It is characterized by the spin Hamiltonian parameters S=1/2, g=1.97±0.06, A=0.068±0.004 cm^-1, I=3/2 (100%) and attributed to the complex formed by an arsenic-antisite defect and an arsenic vacancy on a first-nearest-neighbor position AsGaAs₃VAs. We consider it to be the precursor defect to the isolated antisite defect AsGa{As}₄$, which is subsequently formed by the trapping of a mobile arsenic interstitial by this complex. Contrary to this last defect, the level associated with the 0{→} + transition of the antisite-vacancy complex is shallow with an ionization energy E≤0.35 eV from the conduction band.