Detection of Long Wavelength Photons via Quasi-Two-Dimensional Ternary Ta2NiSe5

Terahertz technologies are of great significance in a wide range of applications, such as astronomy, medicine, communications and nondestructive material characterization. However, the energy of terahertz photons is so small that it is difficult to detect directly at room temperature. Two-dimensional (2D) materials with excellent optoelectronic properties provide opportunities for the development of terahertz photodetectors. Herein, we develop a high-performance terahertz photodetector with a metal-semiconductor-metal structure via a Ta2NiSe5 nanosheet. The photodetector shows an excellent responsivity of 1350 A W-1 and an extremely low noise equivalent power of 0.01 pW Hz-0.5 with a fast response of similar to 550 ns at room temperature. Electromagnetic induced well theory is utilized to explain the highly sensitive terahertz photoelectric response. In addition, long-term stability over 6 months is realized for the detector. The terahertz imaging experiments demonstrate the excellent performance of the detector and potential applications. The results suggest that our strategy can be a strong candidate for high-performance terahertz photodetection systems.