Influence of Cd source concentration on photo-current response property of CdxZn1−xS film prepared by chemical bath deposition

The CdxZn1−xS thin films were prepared by chemical bath deposition in a solution containing cadmium chloride, zinc chloride, thiourea, sodium citrate and ammonia. It was found CdxZn1−xS thin films could be successfully prepared at different CdCl2 concentrations from 0.04 M to 0.01 M. The morphological, structural, optical properties of CdxZn1−xS films fabricated by different Cd source concentrations were investigated by XRD, SEM and UV–vis-NIR spectroscopy, respectively. The CdxZn1−xS films prepared at 0.03 M and 0.02 M CdCl2 showed uniform, dense surface morphology and good crystallinity. With the concentration of CdCl2 in solution decreasing from 0.04 M to 0.01 M, the zinc content increased. Accordingly, the optical band gap increased from 2.45 eV to 3.07 eV. The photo-current response properties were mainly discussed. All the films showed obvious photoconductive phenomenon. The CdxZn1−xS film prepared at 0.02 M CdCl2 showed a best photo-current response, which presented fastest raise-up and fall-down photo-current when the light was turned on and off.