Fabrication and characterization of CuAlO2 transparent thin films prepared by spray technique

CuAlO2 thin films have been grown on glass substrates using spray technique; a low-cost method of thin films depositing. The deposition was carried out in a 450-525 °C range of substrate temperature. The solution and gas flow rates were kept constant at 5 cm3 min−1 and 6.10−3 m3 min−1, respectively. Compressed air was used as a carrier gas. The structural, morphological and optical properties of these thin films have been studied. These properties are strongly related to the substrate temperature and to the [Cu]/[Al] molar ratio r. X-ray diffraction analysis confirmed the initial amorphous nature of as-deposited films and phase transition into crystalline CuAlO2 with the preferential orientation (1 0 1) upon annealing at 570 °C. The optical transmission of 80% has been achieved in the visible spectrum. CuAlO2 band gap energy in the range of 3.34-3.87 eV has been found by optical measurement depending on fabrication parameters.