Photogeneration of donor pairs in ZnSe < Ag > crystals

Experimental evidence is presented that photoinduced defect reactions in Zn Se[Ag] crystals give rise to the formation of (Ag-i(0))(2) interstitial don or pairs. As a result, the induced impurity photoconductivity spectrum show s, along with the band of 0.29 eV due to isolated Ag-i(0) atoms, a series o f narrow bands in the range 0.3-0.6 eV (quasi-line spectrum). The energy po sitions and relative intensities of these bands are accounted for in terms of different pair separations in (Ag-i(0))(2). The charge instability of Ag i under band-gap excitation, associated with multiple electron trapping pro cesses, leads to atomic instability, which gives rise to ionization-enhance d diffusion and the formation of (Ag-i(0))(2) donor pairs.