High Performance of Room-Temperature NbSe2 Terahertz Photoelectric Detector.

Abstract

Photoelectric detection is developing rapidly from ultraviolet to infrared band. However, terahertz (THz) photodetection approaches is constrained by the bandgap, dark current, and absorption ability. In this work, room-temperature photoelectric detection is extended to the THz range implemented in a planar metal-NbSe2-metal structure based on an electromagnetic induced well (EIW) theory, exhibiting an excellent broadband responsivity of 5.2 × 107 V W-1 at 0.027 THz, 7.8 × 106 V W-1 at 0.173 THz, and 9.6 × 105 V W-1 at 0.259 THz. Simultaneously, the NbSe2 photoelectric detector (PD) with ultrafast response speed (∼610 ns) and ultralow equivalent noise power (4.6 × 10-14 W Hz-1/2) in the THz region is realized, enabling high-resolution imaging. The figure of merit (FOM) characterizing the detection performance of the device is 2 orders of magnitude superior to that of the reported THz PDs based 2D materials. Furthermore, the THz response speed is 2 orders of magnitude faster than that of the visible due to the different response mechanisms of the device. Our results exhibit promising potential to achieve highly sensitive and ultrafast photoelectric detection.