An investigation on SILAR deposited Cu_xS thin films


Abstract: A copper sulfide thin film was deposited on glass substrate by successive ionic layer adsorption and reaction method at room temperature, using cupric sulfate and sodium sulfide aqueous solutions as precursors. The structural, surface morphological, optical, and electrical properties of the as-deposited film were investigated via X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, optical absorption, and d.c. 2-point probe methods. The film was found to be amorphous, dense, and uniform. Average atomic percentage of Cu:S in the as-deposited film was calculated as 63:37. The band gap energy of copper sulfide thin film was found to be 2.14 eV and the resistivity was 10^{-2} Omega cm at room temperature. The effect of annealing on crystal structure was also studied and reported. X-ray diffraction patterns revealed that annealing the film at various temperatures slightly improved the crystallinity. By using thermoelectric power measurement, p-type electrical conductivity was determined for as-deposited and annealed samples.

Keywords: SILAR, copper sulfide, thin films, structural properties

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