The growth of ZnMgO alloy films for deep ultraviolet detection

Abstract

ZnMgO films are prepared by RF magnetron sputtering using a composite target and the Mg composition of the samples can be controlled easily even at a high growth temperature. The metal–semiconductor–metal photodetector based on the wurtzite Zn0.6Mg0.4O film exhibits a very low dark current (5 pA at |Vbias| = 3 V) and a high UV/visible rejection ratio (more than three orders of magnitude). The peak responsivity of the photodetector is at around 270 nm and a very sharp cutoff wavelength is at a wavelength of about 295 nm corresponding to the absorption edge of the Zn0.6Mg0.4O film.