Infrared High Polarization‐Sensitive and High‐Responsivity Photodetector Based on 2D Heterojunction Bipolar Transistor

Polarization‐sensitive photodetectors facilitate high‐resolution imaging through the analysis of light's polarization state. As detection systems increasingly demand stringent signal‐to‐noise ratios, achieving high responsivity while maintaining superior polarization selectivity has become a critical challenge. An infrared polarization photodetector with high responsivity is developed using a MoSe 2 /MoTe 2 /MoS 2 heterojunction bipolar transistor architecture operating in the forward‐active mode. This device exhibits broadband response characteristics spanning wavelengths from 532 to 2200 nm. Furthermore, the symmetrical doping of MoSe 2 and MoS 2 monolayers facilitates superior bidirectional photoresponse performance. Under illumination with a 1310 nm laser, the device achieves maximum responsivities of 2.69 and 2.70 A W −1 , detectivities of 3.36 × 10 9 and 2.70 × 10 9 Jones, and external quantum efficiencies of 254.7% and 258.1% at drain‐source voltages (V ds ) of 1 and −1 V, respectively. Notably, defect states in MoS 2 induce distinct polarization‐dependent photocurrent responses. Under 976 nm infrared laser irradiation, the device exhibits exceptional polarization detection capability as evidenced by a photocurrent anisotropy ratio of 39. These findings offer a promising strategy for the design and development of high‐performance, polarization‐sensitive photodetectors.