Negative charge state of the DX center in AlxGa1-xAs:Si.

We present experimental data for the thermally activated capture of electrons on Si-induced impurity states in Al x Ga 1−x As in the strong-lattice-relaxation regime (DX centers). Experiments have been performed after photoionization in the region of transition from the normal to the metastable state of the defect, using hydrostatic pressure up to 8 kbar. An analysis of the isothermal as well as the thermostimulated capture kinetics strongly supports the hypothesis of the negative charge state of the DX center