The n-type Cu2O films were deposited on ITO substrate by three-electrode electrochemical deposition method in a CuSO4-lactic acid electrolyte. The effects of electrolyte pH, bath temperature, and annealing treatment on films’ conductivity and their photoelectrochemical activity were investigated by X-ray diffraction (XRD), photocurrent (I-t) and mott-schottky (M-S) plots. The results show that the n-type Cu2O could be electrodeposited at electrolyte pH of 8.5, 9 and 10, and the electrolyte temperature did not change the films’ conductivity. The highest n-type photocurrent density of 0.014 mA /cm2 and carrier concentration of 2.3×1019 cm-3 was obtained when the electrolyte pH was 8.5 and the bath temperature was 60°C. With increasing annealing temperature from 150°C to 400°C, the photocurrent density and carrier concentration of n-type Cu2O thin films correspondingly increased, indicating that heat treatment is helpful to improve the photoelectrochemical activity.
