High-Performance p-BP/n-PdSe₂ Near-Infrared Photodiodes with a Fast and Gate-Tunable Photoresponse

Van der Waals heterostructures composed of transition-metal dichalcogenide (TMD) materials have become a remarkable compact system that could offer an innovative architecture for advanced engineering in high-performance energy-harvesting and optoelectronic devices. Here, we report a novel van der Waals (vdW) TMD heterojunction photodiode composed of black phosphorus (p-BP) and palladium diselenide (n-PdSe2), which establish a high and tunable rectification and photoresponsivity. A high rectification up to ≈7.1 × 105 is achieved, which is successfully tuned by employing the back-gate voltage to the heterostructure devices. Besides, the device significantly shows the high and gate-controlled photoresponsivity of R = 9.6 × 105, 4.53 × 105 and 1.63 × 105 A W–1 under the influence of light of different wavelengths (λ = 532, 1064, and 1310 nm) in visible and near-infrared regions, respectively, because of interlayer optical transition and low Schottky. The device also demonstrates extraordinary values of detectivity (D = 5.8 × 1013 Jones) and external quantum efficiency (EQE ≈ 9.4 × 106), which are an order of magnitude higher than the currently reported values. The effective enhancement of photovoltaic characteristics in visible and infrared regions of this TMD heterostructure-based system has a huge potential in the field of optoelectronics to realize high-performance infrared photodetectors.