The Electrical Properties of Zinc Selenide Heat-Treated in Controlled Partial Pressures of Constituent Elements

ZnSe single crystals, some of which had been previously heat-treated in molten Zn or doped with Cu, were heat-treated in Zn or Se vapor. The Hall effect and the electrical conductivity were measured and examined as a function of the vapor pressure. Conduction after heat treatment in Se vapor is considered to be dominated by Zn vacancies, Se interstitials, or associated defects containing one of these, while the high n-type conductivity observed after heat treatment in Zn vapor is dominated by Se vacancies or Zn interstitials. With decrease of the acceptor impurity concentration, the transition vapor pressure from low to high conductivity shifts from a high Zn vapor pressure to a low one corresponding to the total pressure minimum.