Solar‐Blind Polarization Sensitive Photodetection Based on β‐ Ga 2 O 3 Microwires With Super‐High Polarization Ratio (>5000) Enabled by Intrinsic and Morphological Anisotropy

ABSTRACT Solar‐blind polarization photodetectors are highly desirable for next‐generation intelligent sensing and imaging systems, yet achieving a high polarization ratio remains a major challenge for current devices. Here, we report a solar‐blind polarization photodetector based on mechanically exfoliated β ‐Ga 2 O 3 microwires, in which intrinsic crystal anisotropy and morphology‐induced anisotropy are synergistically combined to enable enhanced polarization‐sensitive photoresponse. First‐principles calculations reveal that the intrinsic anisotropic optical absorption of β ‐Ga 2 O 3 originates from its low‐symmetry monoclinic crystal structure, leading to polarization‐dependent interband transitions. The finite‐difference time‐domain (FDTD) simulations reveal that the microwire morphology introduces additional polarization‐dependent optical anisotropy. A simple metal‐semiconductor‐metal photodetector is constructed using a single β ‐Ga 2 O 3 microwire, achieving outstanding solar‐blind ultraviolet detection performance with an ultrahigh polarization ratio (PR) of 5200. Furthermore, by integrating the anisotropic photoresponse into a polarization convolution (pCONV) and combining it with an artificial neural network, high‐accuracy fingerprint recognition is achieved with an accuracy of about 99%. This work establishes β ‐Ga 2 O 3 microwires as a promising material for high‐performance solar‐blind polarization photodetection and highlights the effectiveness of morphology engineering in boosting polarization‐sensitive optoelectronic performance.