Effect of local alloy disorder on emission kinetics of deep donors (D X centers) in AlxGa1−xAs of low Al content

We report measurements by deep level transient spectroscopy of electron emission from the deep donor level (DX center) in Si-doped GaAs and AlxGa1−xAs of very low Al content. For the first time, discrete emission rates corresponding to different local configurations of Ga and Al atoms around the Si donor are resolved. The large change in emission kinetics previously observed between GaAs and AlxGa1−xAs (x≥0.14) is thus shown to arise from the local alloy disorder which is absent in GaAs.