2D ReS₂/3D Bi₂O₂Se Homo‐Heterojunction Photodetector Toward Near‐Infrared Polarization Sensitive Detection and High Sensitivity Communication

Abstract Conventional nm‐scale Bi 2 O 2 Se‐based near‐infrared (NIR) photodetectors (PDs) exhibit commendable performance in terms of responsivity and response speed. Currently, the growing complexity of application scenarios requires NIR PDs to possess not only these fundamental functionalities but also the capability for NIR polarization detection and operation well under dim light conditions. Here, this study proposes the 2D ReS 2 /3D Bi 2 O 2 Se homo‐heterojunction PD, which exhibits high photo‐response speed, polarization‐sensitive detection capabilities, and enhanced sensitivity in the NIR spectrum. In detail, a device constructed from µm‐thick Bi 2 O 2 Se demonstrates polarization‐sensitive photodetection at a wavelength of 850 nm, exhibiting a polarization ratio of 1.4 achieved by applied voltage modulation. Based on photogating effect and strong intrinsic absorption, the homo‐heterojunction PD also can detect light power level of nW at 1310 nm, with a response speed of ≈10 µs and responsivity of 34.8 A W −1 at this wavelength. Additionally, this configuration exhibits an outstanding specific detectivity exceeding 10 10 Jones within the wavelength range of 700 to 1310 nm. Even at a cut‐off wavelength of 1550 nm, the device achieves a specific detectivity of ≈10 9 Jones. The ReS 2 /Bi 2 O 2 Se heterojunction NIR PD shows promise for advanced optoelectronic applications due to its high sensitivity and polarization‐sensitive photodetection in NIR band.