Copper oxide thin films were deposited by the drop chemical deposition technique using an aqueous solution containing CuSO4 and Na2SO3. The deposited films were cubic crystalline structure and had O/Cu ratio of similar to 0.77 with a very small amount of sulfur. The surface morphology of the films appeared compact without any crack. In the optical transmission measurement, a clear absorption edge was observed near 800 nm wavelength. Photo-electrochemical measurement confirmed the p-type conductivity and photosensitivity of the films. CuxO-based heterojunctions with ZnO were fabricated, and rectification properties and weak photovoltaic effects were observed. 2012 Elsevier Ltd. All rights reserved.