Achieving Infinite Polarization Ratio in Photodetectors Using In-Plane Anisotropic 2D Materials and Back-to-Back Schottky Structures

Polarization photodetectors offer significant potential in target recognition, quantum physics, and astronomical observations. However, conventional polarization photodetectors often require additional optical components, increasing the devices' complexity and size. Moreover, the limited polarization ratio in photodetectors utilizing anisotropic materials presents a major challenge, hindering their practical applications. In this study, we introduce an innovative approach using a vertically aligned back-to-back Schottky barrier structure, with anisotropic 2D material as the photosensitive unit, to develop a polarization photodetector with an infinite polarization ratio. The distinct differences in light absorption for x- and y-polarizations are crucial in creating a 90° shift in polarization-dependent photocurrents between the top and bottom Schottky diodes. This feature allows for precise modulation of the polarization ratio through bias voltage adjustment, enabling a transition from a finite value to infinity. Significantly high polarization ratios are achieved in ReSe₂- and PdPSe-based devices, with values of 2.89 × 10⁴ and 300, respectively. Our research offers a simplified design for polarization photodetectors with an infinite polarization ratio, presenting significant potential for advancements in optoelectronics.