Fabrication of a Self-Powered β <i>-</i> Ga ₂ O ₃ /PEDOT:PSS Heterojunction for Polarization-Sensitive Ultraviolet Imaging Sensing

Polarization-sensitive deep-ultraviolet (DUV) photodetectors are of great interest for advanced imaging, secure communication, and intelligent sensing, yet their practical application is often hindered by complex device architectures and high power consumption. Here, we report the fabrication of a self-powered polarization-sensitive DUV photodetector based on a β-Ga2O3/PEDOT:PSS heterojunction. Benefiting from the intrinsic anisotropic optical absorption of monoclinic β-Ga2O3 and the built-in electric field at the heterointerface, the device exhibits high polarization-dependent photoresponse without the need for external polarization lens. Under 254 nm ultraviolet illumination, the β-Ga2O3 photodetector exhibits an ultrahigh dichroic ratio of 136, demonstrating its exceptional intrinsic polarization sensitivity. In contrast, the β-Ga2O3/PEDOT:PSS heterojunction photodetector maintains a dichroic ratio of approximately 5 under zero-bias conditions. Using this polarization sensitivity photodetector, a polarization-encrypted ultraviolet image sensor is successfully demonstrated, in which encrypted images are transmitted under one polarization state and accurately decrypted by switching to the orthogonal polarization. This work provides a simple effective strategy for realizing low-power, polarization-sensitive ultraviolet photodetectors and highlights the potential of β-Ga2O3/PEDOT:PSS heterojunctions for secure imaging sensing and advanced optoelectronic applications.