Photoconductivity in CdS:Fe at Liquid Helium Temperature

Abstract

The Morigaki-Hoshina’s model of the optical quenching bands in ESR signal due to the Fe³⁺ ions in CdS was examined and confirmed through photoconductivity measurements at 4.2°K. The observation of corresponding quenching bands in photoconductivity suggests that the bonding level t₂^b should be immersed into the valence band or at least lie at 0.1 meV or near above it. From the features of photoresponse, the presence of the deep lying electron-ejectable centers is concluded in the forbidden gap. The result of photoconductivity measurements in microwave region is also presented which seems to support the results in the d. c. case.