Luminescence and Photoconductivity in Cadmium Sulfide at the Absorption Edge

Abstract

Measurements of optical transmission, photoconductive response, luminescent edge emission, and excitation spectrum for edge emission have been made on single crystal specimens of CdS at 77\ifmmode^\circ\else\textdegree\fi{}K and 4\ifmmode^\circ\else\textdegree\fi{}K. At the lowest temperature there is an energy gap of more than 0.1 electron volt between the absorption edge and the onset of emission. Coupled with information from the emission spectrum and the infrared properties of CdS, this observation suggests that edge emission in this material may occur at a special center and not be characteristic of the pure lattice.