MgxZn1−xO solar-blind photodetector grown by radio frequency magnetron sputtering

Cubic MgxZn1?xO thin films (x = 0.70) were grown on quartz substrates by radio frequency magnetron sputtering and a metal?semiconductor?metal structured photodetector was fabricated based on the film. The photodetector exhibited a dominant response peak at about 225?nm with a cutoff wavelength at about 230?nm, which lies in the solar-blind spectrum range (220?280?nm). A shoulder also appeared in the response spectrum at about 265?nm besides the dominant peak, which resulted from the phase separation in the Mg0.70Zn0.30O thin films as revealed by transmission electron microscopy. The photodetector showed very low dark current (2?pA at 3?V bias).