Zn0.8Mg0.2O-based metal–semiconductor–metal photodiodes on quartz for visible-blind ultraviolet detection

Zn 0.8 Mg 0.2 O 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 ( R 330 nm/ R 400 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 × 10 11 cm Hz 1/2 W −1 at 330 nm.