Structural phase modification in Cu incorporated nanostructured zinc sulfide thin films

• Published in: The Journal of physics and chemistry of solids 2016-08, Vol.95, p.24-36
• Main Authors: Chalana, S.R., Jolly Bose, R., Reshmi Krishnan, R., Kavitha, V.S., Sreeja Sreedharan, R., Mahadevan Pillai, V.P.
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; Band gap renormalization; Copper incorporated zinc sulfide films; Doped films; Doping; Field emission; Localized energy states; Magnetron sputtering; Phase transformation; Phase transformations; Spectroscopy; Surface optical phonon; Thin films; Zinc sulfides
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2016.03.009

Cu incorporated zinc sulfide (ZnS) films are prepared by a RF magnetron sputtering technique and the influence of Cu doping concentration on the structural, morphological and optical properties is systematically analyzed using techniques like grazing incidence X-Ray diffraction (GIXRD), micro-Raman spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and UV–vis spectroscopy. XRD examination of the as-prepared films revealed the presence of polycrystalline structure with co-existence of cubic and hexagonal phases in the pure and lower Cu incorporated films. Increase in Cu doping concentration causes a gradual phase transformation from mixed phase to cubic phase. Micro-Raman spectra further confirms the structural phase modifications with the addition of Cu in ZnS. Morphological analysis shows compact distribution of elongated grain geometry with good connectivity and detectable grain boundary in the pure and Cu incorporated films. Increase in Cu incorporation results in the systematic reduction of RMS surface roughness. EDS analysis confirms the incorporation of Cu and surface vacancy defects in the doped films. All the films are transparent in the visible region and band gap calculation by Tauc plot shows that increase in Cu incorporation results in band gap renormalization. •Cu incorporated ZnS films were prepared by a RF magnetron sputtering technique.•Higher Cu incorporation inhibits the formation of hexagonal phase and increase the formation of cubic phase.•Cu incorporation plays a crucial role in the phase formation of cubic phase of ZnS.•Incorporation of Cu results in band gap renormalization in the as-synthesized ZnS films.