Polarization Signal Amplification of 2D GeSe‐Based Polarization‐Sensitive Photodetectors

Abstract Polarization‐sensitive photodetectors, resolving light intensity, wavelength, and polarization states, enable the characterization of probing microstructure, internal stress, and compositional heterogeneity. Polarizer‐free polarization‐sensitive photodetectors based on in‐plane anisotropic 2D semiconductors offer potential for device miniaturization and on‐chip integration, owing to their inherent linear dichroism and orientation‐dependent carrier mobilities. Hundreds of in‐plane anisotropic 2D materials have been successfully discovered; however, the limited anisotropic photocurrent ratio (PR<10) has hindered the practical application. Herein, a field‐effect transistor (FET)‐based amplification strategy, enhancing PR from 2.1 to 54.8 in 2D GeSe photodetectors is proposed. This significant PR enhancement arises from polarization‐induced resistance variations dynamically modulating gate potentials. Coupled with a steep transistor subthreshold region, small gate fluctuations produce substantial drain current changes, amplifying output anisotropy sensitively. Evaluating four types of FET identifies SMT‐Si transistors as optimal due to their high stability, sharp subthreshold, and excellent noise immunity. In addition, the amplified PR signal directly enhances image contrast and recognition accuracy. Notably, with a high‐PR signal, the machine learning model achieves a recognition rate of 0.99 in only 17 training epochs, reflecting a computational cost reduction of over 60%. This work provides an effective strategy to enhance PR, benefiting from high‐resolution polarization imaging and advanced optoelectronic sensing.