Preparation and characterization of nanocrystalline PbS thin films produced by chemical bath deposition

Abstract

Lead sulfide thin films are deposited on glass substrates at room temperature for 2 h by chemical bath deposition. The structure, surface morphology, optical and electrical properties of the thin films are characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, optical absorption spectroscopy and the Hall effect measurements. The obtained films show the formation of well crystallized PbS with a cubic rock salt structure and with the preferential orientation (111) plane. The lattice parameter and crystallite size of the films are found as a = 600 Å and 62 nm from the X-ray reflectivity data from the atomic force microscopy image, respectively. The band gap width of the films is determined as 2.84 eV. The optical parameters of the films such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant are evaluated. Moreover, from the Hall measurements, electrical resistivity, conductivity carrier mobility, and carrier concentration of the films are determined as 3.722 ω m, 0.268 ω-1 m-1, 8.486×10-1 m2 V-1 s-1, and 1.976×1018 m-3, respectively.