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 MoSe2 photodetector based on geometrically asymmetric contacts is reported for the first time. The device exhibits a high current rectification ratio of ≈104 and a large self-powered photovoltage responsivity of ≈4.38 × 107 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 MoSe2 channel. The simple fabrication process of the geometrically asymmetric MoSe2 diodes along with their high photodetection and diode rectifying performance make them excellent candidates for electronic and optoelectronic applications.