Gallium interstitials in GaAs/AlAs superlattices

Abstract

Optically detected magnetic resonance of point defects in a GaAs/AlAs superlattice is reported for the first time. The spectrum is characterized by g=2.007 and hyperfine coupling, ${}_{}{}^{69}{}_{}{}^{}$A=0.054 ${\mathrm{cm}}^{\mathrm{-}1}$ and ${}_{}{}^{71}{}_{}{}^{}$A=0.069 ${\mathrm{cm}}^{\mathrm{-}1}$, due to Ga. The electronic state has ${\mathit{A}}_1$ symmetry consistent with theoretical predictions for the interstitial Ga atom but not for the ${\mathrm{Ga}}_{\mathrm{As}}$ antisite. Recombination via these defects reduces the intrinsic excitonic emission of the superlattice. The wave function shows no axial perturbation from the nearby potential barriers, demonstrating its localized character.