Electrical and optical properties of Co2+:SnO2 thin films deposited by spray pyrolysis technique

In this work, tin oxide (SnO2) and cobalt doped tin oxide (Co:SnO2) thin films are deposited by spray pyrolysis technique and the influence of doping concentration on the structural, morphological, electrical and optical properties of tin oxide films is analyzed and reported. X-ray diffraction pattern shows that the SnO2 and Co:SnO2 films are polycrystalline in nature and exhibit tetragonal crystal system. Co doping shifts the preferential growth orientation of SnO2 to (200) direction. Scanning electron microscopic studies show that the surface morphology of tin oxide films was effectively modified by various Co concentrations. X-ray photoelectron spectra of 5 at.% Co:SnO2 thin film reveal the presence of tin, oxygen, and cobalt. Carrier concentration and mobility of the SnO2 film decreases with increasing Co concentration and 0.5 at.% Co:SnO2 film acquires a mobility of 74 cm2/V s. The average optical transmittance of SnO2 thin film in the range of 500–800 nm increases due to Co doping.