2D MoSe₂ Geometrically Asymmetric Schottky Photodiodes

Abstract Optoelectronic devices based on geometrically asymmetric architecture have recently attracted attention due to their high performance as photodetectors and simple fabrication process. Herein, a p‐type 2D MoSe 2 photodetector based on geometrically asymmetric contacts is reported for the first time. The device exhibits a high current rectification ratio of ≈10 4 and a large self‐powered photovoltage responsivity of ≈4.38 × 10 7 V W −1 , as well as a maximum photocurrent responsivity of ≈430 mA W −1 along with a response time of ≈2.3 ms under 470 nm wavelength at 3 V bias voltage. The photocurrent responsivity is further enhanced to an ultrahigh responsivity of ≈1615 mA W −1 by applying a gate bias voltage due to the electrostatic modulation of carrier concentration in the MoSe 2 channel. The simple fabrication process of the geometrically asymmetric MoSe 2 diodes along with their high photodetection and diode rectifying performance make them excellent candidates for electronic and optoelectronic applications.