Structural and optical characterization of CdS nanofibers synthesized by dc-sputtering technique

CdS nanofibers have been prepared by direct current-sputtering technique without using any catalyst or matrix. X-ray diffraction patterns and selected area electron diffraction patterns confirmed the cubic CdS phase formation in the thin films, although the initial target material was hexagonal CdS powder. TEM micrographs have confirmed the nanofiber formation with diameters in the range 2–4.3 nm and length of a few microns. XRD patterns showed the crystal size increased with the increase of deposition time. UV–Vis spectra of the films have showed nearly 90% transparency in the visible range and the bandgap is higher compared to that of the bulk material. The direct bandgap increased from 3.06 to 3.56 eV with decrease of deposition time from 20 to 7 min. The crystallite sizes have also been determined from the shift of the direct bandgap with that of bulk CdS and they lie in the range 2.82–3.65 nm.