Polarized vdW Schottky photodiode with high fill-factor and polarization ratio

Against the background of a variety of polarized optical applications, a great number of polarization-sensitive photodetectors based on anisotropic two-dimensional (2D) materials and their heterojunctions have been proposed. However, the low polarization ratio (PR), describing the response sensitivity on the polarization angle of the incident light, is still demanding to be solved. In this work, we demonstrate a van der Waals (vdW) Schottky photodiode comprising 2D semiconductor InSe and semimetal 1T′-MoTe2 for the linearly polarized photodetection. The device exhibits obvious photovoltaic characters with a maximum open circuit voltage (Voc) of 0.51 V and fill factor (FF) up to 0.78, which is the highest value in the vdW heterojunction-based photovoltaic device. Due to the anisotropic in-plane structure of 1T′-MoTe2, our photodiode also shows a strong polarization-sensitive photodetection with a PR value up to ∼22, enabling the practical applications in angle-dependent photodetector and image sensors. This work reports a vdW Schottky heterojunction for polarized photodiode with high FF and polarization ratio, toward the polarization-dependent photovoltaic applications.