Bistable Optical Thin CdS Film Devices: All-Optical and Optoelectronic Features

We have performed experiments on thin (6 µm) spray-deposited CdS films. All-optical and optoelectronic (hybrid) bistabilities were observed at 210 K. We have been successful for the first time in demonstrating that it is possible to reach, in thin CdS films, the same contrasted bistable loops in both transmission and photocurrent. The origin of the bistability is explained by the measured dependence of transmission on temperature. A generalized model based mainly on Urbach's rule is presented for calculating the temperature dependence of transmission. A good agreement between theory and measurement is obtained.