▎ 摘　　要

Terahertz (THz) technology has developed vigorously and demonstrated a wide range of application prospects in various fields, ranging from biomedical and deep space exploration to wireless communications and nondestructive detection. Therefore, the room temperature (RT) sensitive low-power THz detectors are of great technical significance for the development of THz technology. Two-dimensional materials as the superior candidates for next-generation electronics and optoelectronics integrated devices are drawing increasing attention for their unique confined structure and abundant properties. Especially, construction of heterojunction is an alternative method for improving the photoelectric performance of the detectors. Herein, we have demonstrated self-driven and ultra-sensitive RT THz photodetector based on asymmetrically contacted Graphene-Ta2NiSe5 van der Waals heterojunction. Surprisingly, the proposed self-driven THz photodetector is superb with an ultra-fast photoresponse (720 ns), a high responsivity (24.2 mA/W and 18.2 mA/W), and a low noise equivalent power (41 nW/Hz0.5 and 55 nW/Hz0.5) at 0.12 THz and 0.30 THz, respectively. More importantly, the detector achieves high-resolution THz imaging at RT, and the performances of the devices are significantly improved by applying a small bias voltage (100 mV). Our results present the feasibility for realizing superior RT THz detection and exhibit promising prospects in analytical applications, ultrafast sensing and security monitoring.