We have observed photoinduced reactions between pairs of zinc and oxygen impurities in gallium phosphide. From photoluminescence studies we find that the nearest-neighbor (Zn, O) pairs are dissociating, after which they re-form as further separated pairs. The activation energy for the dissociation is found to be 0.60±0.07 eV for the photoinduced reaction, and 2.6±0.6 eV for the purely thermal reaction. We tentatively identify the photoinduced reaction as being due to excitation of local phonon modes by nonradiative electron-hole recombination.

• Received 6 July 1981

DOI:https://doi.org/10.1103/PhysRevLett.47.925