A study of the photoconducting properties of CdSSe(Cu) with a view to its use in solid-state image intensifiers

Abstract

Photoconductive characteristics of CdSSe(Cu) in a silicone resin binder layer have been studied in a configuration similar to that under actual use in a solid-state image intensifier (SSII). The dark current was measured for various fields and at different temperatures. The dependence of photocurrent on applied voltage, temperature, and intensity and wavelength of incident light has also been studied. The observed space-charge-limited photocurrent for high illumination and fields is ascribed to non-uniform illumination of the sample. The intensity dependence of photocurrent suggests an exponential trap distribution, which also explains the response time variation with temperature. Spectral studies indicate an increase in the red sensitivity over that expected on the basis of the band gap. This has been attributed to the filtering effect of selective absorption. The photocurrent to dark current ratio is shown to be greater than 104 for the light intensities and voltage used. It has been concluded from the above studies that CdSSe(Cu) can be used in SSII.