Effect of Ga doping on structural, morphological, optical and electrical properties of CuO thin films deposited by spray pyrolysis technique

Copper oxide (CuO) and gallium (Ga) doped copper oxide thin films were fabricated using spray pyrolysis technique under normal atmosphere. The films were deposited onto a glass substrate at a temperature of 380 °C and their subsequent properties were examined and discussed. XRD analysis confirms that the deposited films have the monoclinic phase of cupric oxide (CuO). SEM image reveals that the pure CuO film has nano-fiber like morphology, which changes considerably with Ga doping. EDX exploration ensures that the fabricated films contain the desired copper, oxygen and gallium elements. The transmittance of CuO thin film decreases as doping level of Ga increases up to 2%, after which it increases. The absorption coefficient and optical band gap of CuO thin film also found to changes with Ga doping. However, Ga doping enhances the photo response capability of CuO thin films up to a specific level of doping. It has been found that the CuO thin film has a resistivity of 5.69 × 102 (ohm-cm) and 2% Ga-doped CuO thin film exhibited the lowest electrical resistivity. The obtained results of the Hall Effect measurement indicate that the carrier of the CuO thin film is p-type, and it interestingly changes to n-type due to the doping of Ga.