Structural and optical properties of CuS-ZnS nanocomposite films containing different at% of Zn

CuS-ZnS nanocomposite films were synthesized through the interaction of H2S gas with nanostructured Cu-Zn films deposited through vacuum evaporation technique at a relatively high pressure of an inert gas. The film samples were synthesized for four different atom% of Zn. XPS analysis showed that both Cu and Zn existed in the +2 oxidation state in the samples. XRD patterns showed that in the samples, CuS and ZnS existed as separate phases and hence the samples were copper sulphide-zinc sulphide nanocomposite films. Also, HRTEM image and SAED pattern of the sample containing the highest atom% of Zn confirmed the co-existence of both CuS and ZnS phases in the sample. The grain size of CuS which was the major phase in the CuS-ZnS nanocomposite films decreased with increase in the atom% of Zn. Red shift of the Raman modes of CuS phase in the samples was an indication of substitutional doping of Zn into the CuS lattice. Analysis of optical absorption and reflection spectra of the samples indicated the possible application of the films as window layer in solar cells.