Characterization of Mg0.20Zn0.80O metal–semiconductor–metal photodetectors

Mg0.20Zn0.80O films have been prepared on quartz substrates by using radio frequency (RF) magnetron sputtering, and metal–semiconductor–metal (MSM) structured photodetectors have been fabricated on the Mg0.20Zn0.80O films employing interdigital Au as metal contacts. We have investigated the effects of electrode spacings on the properties of Mg0.20Zn0.80O MSM photodetectors. It was shown that both of dark currents and responsivities of the devices will decrease with the increasing electrode spacing at the same bias. It was thought that the resistance and the depletion region between the electrodes play important roles in the devices, and the physical mechanism can be explained by a straightforward qualitative model.