The microstructure of copper oxide layer on zinc oxide is optimized via a two-step electrodeposition method to create potential composite electrodes for photoelectrochemical cells. By optimizing the deposition temperature, the microstructure and photocatalytic properties can be fundamentally modified. The strategy includes the potentiostatic deposition of zinc oxide layer in the initial step following galvanostatic deposition of copper oxide at selected bath temperature, including 30, 40, 50, and 60 degrees C. In all cases, the copper oxide layer deposited at 40 degrees C significantly improves the photoanodic current density. Also, the microstructure and optoelectrical properties of the composite films are characterized by electron microscopy, impedance spectroscopy, Mott-Schottky, and solar simulation measurements. It is found that variation in copper oxide deposition temperature affects the electron-hole recombination process and photocatalytic performance.