Spectral response of CdS with Ag, Cu, and in impurities

Abstract

High-resistance (ρdark ≈ 108 Ω · cm) photosensitive CdS samples (ρlight ≈ 102–103 Ω · cm at saturation) were obtained from low-resistance (ρ ≈ 0.1 Ω · cm) nonphotosensitive CdS single crystals by thermal diffusion of Cu, Ag, and In in vacuum at 2 · 10−5 torr. The spectral response of impurity and pure high-resistance photosensitive single-crystal CdS samples was studied in the wavelength range from 0.35 to 3μ. The short-wave and long-wave limits of the spectral curves, the wavelength range of maximum photoconductivity and the forbidden band width, the depth of impurity levels, the upper edge of the impurity band, and the depth of maximum-density activation centers have been determined from the spectral curves. The results are discussed and compared with published data.