Influences of Heat-treatment upon Cadmium Sulphide Single Crystals

Abstract

Ionization energies and electron trap depths in cadmium sulphide single crystals heat-treated in vacuum or in oxygen were obtained by measuring the dark conductivity as a function of the temperature and the thermally stimulated current, respectively. It was found that, in the case of crystals heat-treated in vacuum, the ionization energies were 0.04 eV, 0.7 eV, 1.0 eV and 1.4 eV, and the major electron trap depth was 0.50 eV below the conduction band, and the dark conductivities and the concentrations of the electron traps were reduced as the crystals were heat-treated in oxygen. And when the crystals were heat-treated in vacuum or in oxygen, it was found that the sensitivity of photocurrent at about 600 mμ was increased.