The growth of ZnMgO alloy films for deep ultraviolet detection

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 Zn(0.6)Mg(0.4)O film exhibits a very low dark current (5 pA at vertical bar V(bias)vertical bar = 3V) 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 Zn(0.6)Mg(0.4)O film.