Ambient-Sensitive Photoelectronic Behavior of CdS Sintered Layers

Abstract

The temperature dependence of the equilibrium conductivity and the temperature and illumination dependence of the steady-state and transient photoconductivity of Cu and Cl doped sintered CdS layers are strongly affected by atmospheric oxygen. It is shown that the surface state due to chemisorbed oxygen determines the steady-state photoconductivity and the equilibrium dark conductivity in the adsorbate ambient. Further, an oxygen chemisorption surface state, 0.9 eV below the conduction band, together with the associated surface space-charge region cause the photocurrent to undershoot the equilibrium current upon cessation of illumination, and to overshoot the steady-state photocurrent on reillumination.