Simple metal/SiO2/Si planar photodetector utilizing leakage current flows through a SiO2 layer

Abstract

Silicon wafers covered with a thermally grown high-quality SiO₂ layer were often used as the substrate to house different nanostructures to fabricate photodetection devices. No reports have ever challenged directly fabricating photodetectors utilizing leakage current through non-high-quality SiO₂ films and the intrinsic light absorption properties of Si. Herein, we show that metal/SiO₂/Si planar photodetectors could be easily fabricated by simply depositing two metal electrodes (such as, Au, Ag and Al) on top of SiO₂/Si wafer in which the SiO₂ layer is of non-high quality. The responsivity, stability, photoresponse characteristics and light intensity sensitivity are systematically evaluated. Our results clearly show that the present conveniently and cost-effectively fabricated metal/SiO₂/Si planar photodetectors are of great advantage as compared to many of the nanostructure-based photodetectors constructed on SiO₂/Si substrate.