Chemical bath deposited CdxPb1−xS solid solution films: composition, structure, and optical properties

Abstract

Films of cubic substitutional CdxPb1−xS solid solutions have been synthesized by the chemical bath deposition with varying cadmium acetate salt Cd(CH3COO)2 in the reaction mixture within 0.01–0.08 mol/l on quartz substrates. The crystal structure, chemical composition and morphology were studied by the X-ray diffraction, scanning electron microscopy, elemental analysis, Auger spectroscopy, and Raman spectroscopy, as well as the evolution of the optical and photoelectric properties was determined. The thickness of the deposited films changes from ~ 0.4 to ~ 1.0 μm, and the content of cadmium x in the CdxPb1−xS solid solution varies from 0.036 to 0.090. All the CdxPb1−xS films have B1 crystal structure (NaCl type), but differ in the morphology (the size, form and predominant orientation of the particles forming the films). Forming the substitution solid solution is confirmed by the shift of the Raman lines at 72 and 134 cm−1 toward higher frequencies. The optical band gap determined from the absorption spectra varies from 0.46 to 0.70 eV. The dependences of the photoresponse value (volt-watt sensitivity) and the dark resistance on cadmium acetate concentration in the solution are represented.