High-resolution Laplace transform deep-level transient spectroscopy was used to study the influence of the local environment of the defect upon electron emission from DX centers which were related to group-IV (Si) donors in AlxGa1-xAs, where x was between 0.20 and 0.76, and in -doped GaAs and to group-VI (Te) donor elements in AlxGa1-xAs, where x was between 0.25 and 0.73, and in GaAs0.35P0.65. Experimental evidence indicated that substitutional-interstitial atomic motion was responsible for DX behavior and for associated metastability effects. The atom which was subjected to this transition was the Si of DX(Si) itself and, in the associated spectra, only 1 group of peaks was observed for AlGaAs. In the case of DX(Te), it could involve either Ga or Al; thus producing 2 groups of peaks in AlGaAs and 3 or 4 broad emission bands in GaAs0.35P0.65. These results ruled out the possibility that DX-type defect states were caused by a donor atom in a stable substitutional position with a small lattice relaxation or with a fully symmetrical large lattice relaxation.

L.Dobaczewski, P.Kaczor, M.Missous, A.R.Peaker, Z.R.Zytkiewicz: Journal of Applied Physics, 1995, 78[4], 2468-77