Zn_0.8Mg_0.2O-based metal–semiconductor–metal photodiodes on quartz for visible-blind ultraviolet detection

Abstract

Zn0.8Mg0.2O metal–semiconductor–metal ultraviolet photodiodes were fabricated on quartz by radio frequency magnetron sputtering. Dark current, spectral responsivity and pulse response experiments were carried out for the device. The photodetectors showed a peak responsivity at 330 nm. The ultraviolet-visible rejection ratio (R330 nm/R400 nm) was more than four orders of magnitude at 3 V bias. The photodetector showed fast photoresponse with a rise time of 10 ns and a fall time of 170 ns. In addition, the thermally limited detectivity was calculated to be 3.1 × 1011 cm Hz1/2 W−1 at 330 nm.