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.