AbstractThe photoresponse of a Pt/MgxZn1–xO Schottky photodiode using a (0001) ZnO single crystal substrate grown by the hydrothermal growth method is described in this report. MgxZn1–xO thin films were prepared by a reactive RF magnetron sputtering method on the Zn‐face of the ZnO single crystal substrate. The prepared MgxZn1–xO thin films had a band gap of 4.1 eV. The fabricated Schottky photodiode had high responsivity of 0.034 A/W at the wavelength of 250 nm, and the responsivity ratio at wavelength of 250 nm and 550 nm was of the order of 4. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)