Studies on Dilute Magnetic Semiconducting Co-Doped CdS Thin Films Prepared by Chemical Bath Deposition method

The Co-doped CdS polycrystalline thin films were deposited onto the glass substrates by chemical bath deposition method. All the deposited films were characterized for structural, surface morphology, elemental, optical and magnetic properties using X-ray diffractometer, scanning electron microscopy (SEM), energy dispersive X-ray, UV–Vis. NIR spectrometer and Vibrating sample magnetometer before and after doping. The thin films exhibit hexagonal wurtizite structure with (0 0 2) preferential orientation and the calculated crystallite size is 29 and 18 nm for pristine and Co-doped CdS films respectively. X-ray photoelectron spectroscopy (XPS) analysis showed the presence of Cd, S and Co peaks along with O 1s peak. The studies revealed that the surface Cd atoms of films are found to be bound either to S atoms or O atoms. SEM images showed grainy surface for pristine which gets modified under Co doping. Energy dispersive analysis using X-rays confirmed the presence of Cd, S and Co in the films. From optical transmittance spectra, the bandgap was estimated and found to be varying from 2.4 to 2.27 eV with the increase of Co concentrations. The room-temperature ferromagnetic behavior was exhibited by Co-doped CdS films.