CHARACTERIZATION OF CHEMICALLY-DEPOSITED SILVER SULFIDE THIN FILMS

Abstract

Ag 2 S thin films have been deposited onto fluorinated tin oxide (FTO)-coated conducting glass substrates using chemical bath deposition (CBD) method. Photoelectrochemical (PEC) cell, optical properties, surface morphology, structural properties, compositional analysis and electrical properties of Ag 2 S thin films have been investigated. The PEC measurements indicate that the deposited Ag 2 S layers are n-type in electrical conduction. The transmittance of deposited layer is obtained to be about 13–87%. The absorbance of the films is found to decrease with increasing wavelength. The band gap of the Ag 2 S thin film is estimated to be 1.8 eV. It is observed from scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements that the substrates are well-covered with the deposited Ag 2 S layers without cracks and pinholes. The grain size of Ag 2 S thin films is estimated from SEM measurements to be in the range 100–210 nm. The mean roughness of Ag 2 S films is found from AFM measurements to be in the range 7.20–15 nm. X-ray diffraction shows that the films are well-crystallized and the deposited layers are mainly consisting of Ag 2 S phase with (-103) preferential plane. EDX analysis shows that a nearly stoichiometric composition of Ag 2 S is obtained. The resistivity is estimated to be in the range 3.5–7.0 Ω-cm.