EFFECTS OF THE LOCAL ENVIRONMENT ON THE PROPERTIES OF DX CENTERS IN SI-DOPED GAAS AND DILUTE ALXGA1-XAS ALLOYS

Si-doped GaAs and dilute AlxGa1-xAs alloys under hydrostatic pressure have been studied using deep level transient spectroscopy (DLTS). In GaAs the DLTS spectrum of the DX center is a single peak. In AlGaAs however, multiple peaks, resulting from different thermal emission rates from donors having different numbers of Al atoms as near neighbors, are observed. The pressure dependence of the electron occupation of individual DX levels shows that the larger the number of Al atoms near the Si donor, the lower the energy position of the DX level.