High-responsivity, high-detectivity, broadband infrared photodetector based on MoS₂/BP/MoS₂ junction field-effect transistor

Sensitivity stands as a critical figure of merit in assessing the performance of a photodetector and can be characterized by two distinct parameters: responsivity or detectivity. Simultaneous optimization of these two parameters is essential to ensure the applicability of a single detector across various scenarios, yet it remains a persistent challenge for mid-infrared photodetector. Here, we demonstrate that the construction of a photoconductive detector based on a MoS2/BP/MoS2 npn junction field-effect transistor configuration can effectively balance the tradeoffs between photoresponsivity and detectivity. In this device, the black phosphorus layer serves as the channel, while the top and bottom MoS2 layers act as photogates to boost the photocurrent. Consequently, a high-performance room-temperature-operating mid-infrared photodetector with a responsivity and detectivity reaching 9.04 A W-1 and 5.36 x 10(9) cm Hz(1/2) W-1 (1550 nm), and 7.25 A W-1 and 4.29 x 10(9) cm Hz(1/2) W-1 (3600 nm) is achieved. Our study provides an alternative structural design, enabling the applications of mid-infrared photodetectors across multiple scenarios.