• A large scale CuO film is prepared on Si substrate tightly by ozone etching and annealing. • The film consists of a dense polycrystalline nanoplate array. • The film is fabricated into a schottky contacted diode with Al electrodes. • The diode performs a large rectifying ratio and a highly sensitive. Schottky contacted sensors are of promising photoelectric devices due to the intrinsic high selectivity and high sensitivity properties. However, it is still a challenge to construct a stable contacted semiconductor material in Schottky sensors. In this work, a CuO film was prepared by an ozone etching and annealing on a silicon wafer substrate. Material characteristic investigation shows that the film composed of a highly dense polycrystalline nanoplate arrays film. The film is also used to fabricate a schottky diode with aluminum electrode to test its photoelectric performance. The test results indicate that the diode has a large rectifying ratio and a highly sensitive photoreponse effect. This work provides a new facile CuO nano arrays material process for Schottky contacted sensor application.