Gate-Tunable Photodetectors Based on Anti-Ambipolar Transistors Composed of Black Phosphorus/MoS₂ Nanosheet Heterostructures

Abstract

Anti-ambipolar transistors (AATs) based on two-dimensional (2D) van der Waals heterostructures are frequently studied to create multivalued logic circuits. However, the anti-ambipolar characteristics arising from the gate-tunable energy band structure can also provide discrete photoresponses at various gate voltages, which can be used to produce high-performance photodetection. Here, we demonstrate a high-performance black phosphorus/molybdenum disulfide (BP/MoS2) two-dimensional material heterostructure AAT. The peak-to-valley ratio of the AAT reaches 104 by controlling the conductivity of BP and MoS2 through the gate voltages. More importantly, the BP/MoS2 AAT shows an apparent gate-tunable photoresponse in the visible (450, 532, and 633 nm) and infrared wavelength range (1550 nm) and exhibits a strong photoresponse in the driving voltage range, which is attributed to the modulation of the gate voltage on the band structure and carrier transport. In addition, the type II band alignment and photogating effect in the heterostructure can facilitate the separation of photoexcited carriers, leading to high-performance photodetection with a high detectivity of 5.3 × 1013 Jones and a high responsivity of 3.8 × 104 A/W. Our work demonstrates the promising prospects of 2D material AATs for application in optoelectronic devices.