The effect of Cu-doping on physical properties of nanostructured NiO thin films prepared by spray pyrolysis technique

Undoped and copper doped nickel oxide films, prepared onto glass substrate by spray pyrolysis method, were studied from various physical view points including: morphological, structural, optical, electrical and thermo-electrical properties. The XRD patterns show the nano-sized grains have cubic polycrystalline nature (with no additional related Cu-content phase) and the data analysis revealed while the crystallite sizes are decreased (13-10.5 nm) the dislocation density are increased (5.92×10-3 - 9.07×10-3 nm-2) with increments in the doping density. The electrical and thermo-electrical data (Seebeck effect) confirmed more substitutions of Cu ions with Ni2+ ions and in turn more p-type conductivity in samples with higher doping. Optical measurements showed the direct and indirect band gaps of the transparent conductive layers are decreased. These variations are in good agreement with the variations of the crystallite sizes and carrier densities of the samples