Influence of substrate temperature on physical properties of CuAlO2 thin films grown via nitrate route pyrolytic reaction

•Synthesis CuAlO2 thin films by ultrasonic spray pyrolysis using nitrate precursors.•Substrate temperature influenced the physical properties of films.•C axis preferred orientation CuAlO2 film is observed.•Wide bandgap of 3.60 eV and densely packed and uniform morphology can be obtained.•p-CuAlO2/n-Si diode with high rectification ratio was successfully formed. CuAlO2 thin film was successfully produced by chemical solution deposition process via ultrasonic spray pyrolysis (USP) technique on n-type Si substrate using nitrate as precursors. The effects of deposition temperature on structural, optical and electrical properties were investigated. The Scanning Electron Microscope (SEM) micrograph showed that the morphological feature of the film is highly influenced by the deposition temperature. The XRD characterization revealed that the produced CuAlO2 film has c-axis crystal orientation. The film showed high rectifying nature of diode in a junction of p-type CuAlO2/n-type Si with turn on voltage approximately 0.5 V. The highest current density of J = 0.86 mAcm−2 at forward bias of 5 V was observed for the film deposited at 600 °C.