Enhancement of the photoresponse in chemical bath deposited PbS thins films by Br impurities

Improvement of the: photoresponse of PbS polycrystalline thin films prepare d by Chemical Bath Deposition (CBD) is normally achieved by the addition of oxidants into the bath [1-3]. In the present work the alternative use of h alogen impurities (bromine ions) is proposed. A dependence of the photoresp onse and the morphology of the deposited films on the Br concentration in t he bath is observed. The temperature behaviour of the film dark conductivit y is analysed. At a critical temperature T-c, at which the barrier height a s well as the width of the space-charge ge region near the grain boundaries approaches to zero a crossover from the barrier-limited to the mobility-li mited conductivity mechanism takes place.