Gate-Tunable Photovoltaic Behavior and Polarization-Sensitive Near-Infrared Photodetector Based on GeS2/MoTe2 Heterostructure

Self-powered photodetectors, which operate without the need for an external power supply, play a pivotal role in addressing the growing demands for low power consumption, environmental sustainability, and device miniaturization. These next-generation photodetectors have garnered significant attention due to their exceptional attributes, including high photoresponsivity, low dark current, and rapid photoresponse. GeS₂ and MoTe₂ materials, owing to their unique structural characteristics and superior optoelectronic properties, have been extensively explored for self-powered photodetection applications. In this work, we present a gate-tunable photovoltaic behavior and polarization-sensitive near-infrared (NIR) photodetector based on GeS₂/MoTe₂ heterojunction. Under 850 nm illumination with an incident power density of 63.42 mW/cm², the device exhibits a high responsivity of 1.09 A/W and a specific detectivity of 1.42 × 10¹⁰ Jones at zero bias, along with a fast response time of 56 ms. By applying a gate voltage, the photovoltaic performance can be effectively modulated, with the responsivity enhanced to 8.3 A/W and the detectivity improved to 1.09 × 10¹¹ Jones under a gate bias of –8 V. Furthermore, due to the anisotropic optical properties of GeS₂, the device demonstrates pronounced polarization sensitivity. Leveraging its outstanding NIR performance, the GeS₂/MoTe₂ photodetector is integrated into a multiband antibiotic concentration detection system, enabling efficient, accurate, and eco-friendly monitoring of antibiotic levels.