ZnO thin films were grown by remote plasma enhanced MOCVD. Diethyl zinc (DEZn) were used as group-II source. Oxygen gas were used as group-VI source, and VI/II ratio was controlled by varying flowing quantity of oxygen gas. The surface morphology of ZnO thin film is shape like the rod when VI/II ratio is small. It has changed into a smooth surface by increasing VI/II ratio. And the carrier concentration of ZnO thin film has been decreased from 5E+18 cm-3 to 5E+17 cm-3 by changing VI/II ratio. MgxZn1-xO UV detectors were fabricated and evaluated. An excellent cutoff characteristic was obtained form MgxZn1-xO UV detectors , and wavelength has changed from 370 nm to 350 nm.