Short‐Wave Infrared Photodetectors Based on β‐In2Se3/Te Heterojunctions for Optical Communication and Polarimetric Imaging Applications

Polarization‐sensitive infrared photodetectors have vast application prospects in imaging systems and polarization sensors due to the addition of new detection dimensions beyond wavelength and intensity. However, most polarization‐sensitive photodetectors are operated in the visible wavelength range and still encounter challenges of limited responsivity (R) and polarization ratio (PR) under short‐wave infrared illumination. To address these issues, a vertical heterostructure of β‐In2Se3‐on‐Te is reported, achieving high‐performance and polarization‐sensitive imaging sensors in the short‐wave infrared (SWIR) region. The high R (2 A/W at 1310 nm and 0.71 A/W at 1550 nm) and specific detectivity (2.14 × 109 Jones at 1310 nm and 7.3 × 108 at 1550 nm) are obtained, which surpasses most photodetectors using anisotropic 2D material in the infrared range. Considering the strong anisotropic nature of Te nanosheets, the device exhibits notable polarization sensitivity with a PR value of 4.95 under 1310 nm laser irradiation. This work proposes a multifunctional photodetector for the great applications of ASCII code transmission and polarization‐sensitive infrared imaging, offering a new opportunity for versatile angle‐resolved optoelectronics in the infrared communication band. To achieve the short‐wave infrared polarization‐sensitive photodetectors, vertical β‐In2Se3/Te heterojunction is assembled. Due to the type‐II band alignment and photo‐gating effect, the heterojunction exhibits excellent responsivity (2 A/W at 1310 nm and 0.71 A/W at 1550 nm). Moreover, the device demonstrates superior polarization sensitivity with anisotropic photocurrent ratio of ≈4.95 in 1310 nm, which paves the way for polarimetric imaging.