Effects of variable Cd doping concentrations on structural and optical properties of SILAR grown SnO2 thin films

Cadmium doped tin oxide thin films have been deposited by successive ionic layer adsorption and reaction method. The physical properties were analyzed to assess the impact of cadmium doping on tin oxide nanostructures, such as structural, morphological, and optical. X-ray diffraction spectra revealed that the polycrystalline samples have tetragonal crystalline structure with preferential orientation along (110) plane. Grain size was found to vary between 15.73 nm and 20.98 nm as impurity concentration changed in the grown tin oxide films. Also, scanning electron microscopy images disclosed that the produced films possess non-uniform crystallite structures with mainly spherical shapes. X-ray photoelectron spectroscopy verified the presence of tin, oxygen and cadmium elements for doped samples. UV???vis spectroscopy was used to determine optical band gap energy which increased from 2.5 eV to 2.76 eV due to the cadmium doping. In photoluminescence spectra, three main emission peaks were obtained which were located at 400 nm, 540 nm, and 750 nm. Also, the obtained results were compared with the previous works which employed other deposition methods to fabricate cadmium doped tin oxide films.