INCORPORATION OF CU-ZN CENTERS IN ZNSE FAR FROM EQUILIBRIUM

An investigation employing nuclear transmutation to probe the effects of copper doping in ZnSe is presented. Three experimental techniques a re developed in the investigation. With the first, as-grown ZnSe is ir radiated with thermal neutrons which results, after thermal annealing, in the incorporation of Cu-Zn, centers. Observations are consistent w ith isolated Cu-Zn being involved in the copper red and copper green e missions in ZnSe but not in the I-l(d) excitonic emission. With the se cond, it is shown that zinc annealing can be used effectively in inves tigations involving the irradiation of as-grown ZnSe since the zinc an nealing treatment significantly reduces background PL emissions in bul k ZnSe. The third technique employs homoepitaxial ZnSe layer growth fr om previously irradiated elemental sources. The epitaxial layers displ ay no dominant I-l(d) excitonic emission and a very low level of deep emissions. Because, with the techniques described here, the copper ato ms are introduced at zinc sites after crystal growth processes are com plete, the copper atoms are notable to interact with other dopants or lattice defects during growth as they can when incorporated by other m eans. The absence of interactions during crystal growth permits the un ambiguous incorporation, far from equilibrium, of isolated Cu-Zn cente rs in ZnSe. Copyright (C) 1996 Elsevier Science Ltd