Bi influence on growth and physical properties of chemical deposited PbS films

Abstract

PbS films were chemically deposited on glass substrates from chemical reducing bath doped with Bi. The growth and properties of PbS layers are investigated. The effect of the reducer and Bi 3+ ions on the deposition process was studied with a quartz-crystal microbalance technique. The reducer introduces a new deposition mechanism of electrochemical nature, which allows for thicker films. On the other hand, Bi 3+ ions introduce nucleation centers in the solution (Bi(OH) 3), which accelerate the homogeneous precipitation and diminish the film thickness. The PbS grain size within the layer increases with increasing the Bi content in the deposition bath. A considerable enhancement of the photoconductive signal was found in case of PbS films deposited from Bi doped bath. The signal has nonlinear behavior with the Bi content in the chemical bath. There is an optimum quantity of Bi for which the photoconductive characteristic reaches maximum.