Abstract:MgxZn1-xO is a promising material for developing solarblind ultraviolet(UV) photodetectors. However, the control of the MgZnO quality and the phase separation with increase of Mg in MgxZn1-xOO alloy is still a difficult problem. Up to now, no reports that the cutoff wavelength is at 273 nm have been found for the photodetectors based on MgZnO films. In this paper, cubic MgxZn1-xOO thin films are grown on quartz and sapphire substrates by Radio Frequency(RF) magnetron sputtering and Metal Organic Chemical Vapour Deposition(MOCVD). The MetalSemiconductorMetal(MSM) structured MgZnO photodetectors are fabricated based on the films. Results from spectral analysis shows that the photodetector exhibits a peak response wavelength at 225 nm with a cutoff wavelength of 230 nm, and the cubic phase MgZnO alloy with 255 nm absorption edge is finished by LPMOCVD and the MSM devices exhibit the peak energy at 250 nm with cutoff wavelength of 273 nm, which lies in the solarblind spectrum range(220~280 nm).