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

Anti-ambipolar transistors (AATs) based on two-dimensional(2D)van der Waals heterostructures are frequently studied to create multivaluedlogic circuits. However, the anti-ambipolar characteristics arisingfrom the gate-tunable energy band structure can also provide discretephotoresponses at various gate voltages, which can be used to producehigh-performance photodetection. Here, we demonstrate a high-performanceblack phosphorus/molybdenum disulfide (BP/MoS2) two-dimensionalmaterial heterostructure AAT. The peak-to-valley ratio of the AATreaches 10(4) 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) andexhibits a strong photoresponse in the driving voltage range, whichis attributed to the modulation of the gate voltage on the band structureand carrier transport. In addition, the type II band alignment andphotogating effect in the heterostructure can facilitate the separationof photoexcited carriers, leading to high-performance photodetectionwith a high detectivity of 5.3 x 10(13) Jones and ahigh responsivity of 3.8 x 10(4) A/W. Our work demonstratesthe promising prospects of 2D material AATs for application in optoelectronicdevices.