Metal–insulator–semiconductor–insulator–metal structured titanium dioxide ultraviolet photodetector

Titanium dioxide (TiO2) thin films were prepared by an atomic layer deposition technique and a metal–insulator–semiconductor–insulator–metal structured ultraviolet photodetector was fabricated from the TiO2 thin films. Meanwhile, a metal–semiconductor–metal structured photodetector was also fabricated under the same condition for comparison. By measuring their photoresponse properties, it was found that the existence of an insulation layer is effective in improving the photodetector’s responsivity. The mechanism for the improvement has been attributed to the carrier multiplication occurring in the insulation layer under a high electric field. (Some figures in this article are in colour only in the electronic version)