A broadband, self‐powered, and polarization‐sensitive PdSe 2 photodetector based on asymmetric van der Waals contacts

Abstract Self‐powered photodetectors with broadband and polarization‐sensitive photoresponse are desirable for many important applications such as wearable electronic devices and wireless communication systems. Recently, two‐dimensional (2D) materials have been demonstrated as promising candidates for self‐powered photodetectors owing to their advantages in light–matter interaction, transport, electronic properties, and so on. However, their performance in speed, broadband response, and multifunction is still limited. Here, we report a PdSe 2 photodetector with asymmetric van der Waals (vdWs) contacts formed by using a homojunction configuration. This device achieves a high responsivity approaching 53 mA/W, a rise/decay time of about 0.72 ms/0.24 ms, and a detectivity of more than 5.17 × 10 11 Jones in the visible‐near infrared regime (532–1470 nm). In addition, a linear polarization‐sensitive response can be observed with an anisotropy ratio of 1.11 at 532 nm and 1.62 at 1064 nm. Furthermore, a strong anisotropic response endows this photodetector with outstanding polarization imaging capabilities, realizing a contrast‐enhanced degree of linear polarization imaging. Our proposed device architecture demonstrated the great potential of PdSe 2 ‐based asymmetric vdWs contacts for high‐performance photodetectors operating without any external bias.