Synthesis and Surface Characterisation of Cu-Doped Tin Oxide Thin Film for Optoelectronic Applications.

Copper doped tin oxide thin film was synthesised by electrodeposition technique. Film growth was maintained at  cathodic potential of 1.60 V at a varied deposition time. Surface morphological studies of the deposited films were  achieved by field emission scanning electron microscopy (FE-SEM). The scanning electron microscopy image revealed  evenly distributed films, across the substrate with rice-like or dome-like particles, depending on the deposition time.  Post-annealing enhanced films crystallinity and particles agglomeration. Energy disperse X-ray spectra revealed the  elemental constituents present in the film. The results obtained from electrical characterisation of the samples showed  the ohmic properties of the deposited sample. X-ray diffraction results indicated that samples are polycrystalline in  nature with tetragonal rutile structure. The average interplanar spacing and crystallite size of the samples were estimated  as 2.93 Å and 202.5 Å respectively. Optical characterisation of the samples showed that absorption and transmittance  across the ultraviolet-visible spectrum range depend on deposition time. The estimated energy band gaps of 3.06 eV  suggested the films as good candidates for transparent contact electrodes in optoelectronic applications.