Optically Induced Migration of Interstitial Zinc in ZnSe: Caught in the Act

Optically detected EPR studies of zinc-vacancy--zinc-interstitial Frenkel pairs produced by 2.5 MeV electron irradiation at 4.2 K in ZnSe reveal transformations between pairs of differing separations induced by optical excitation at cryogenic temperatures. The interstitial is identified as the mobile constituent by directly observing its conversion between Td sites surrounded by four Se atoms and those surrounded by four Zn atoms. The interstitials, therefore, have been caught in the act of a single recombination-enhanced diffusion half jump, uniquely revealing the exact path taken in the one-jump diffusion process.