Tunneling-based rectification and photoresponsivity in black phosphorus/hexagonal boron nitride/rhenium diselenide van der Waals heterojunction diode†
Tunneling-based van der Waals (vdW) heterostructures composed of layered transition metal dichalcogenides (TMDs) are emerging as a unique compact system that provides new research avenues in electronics and optoelectronics. Here, we designed a black phosphorus (BP)/rhenium diselenide (ReSe2) and black phosphorus (BP)/hexagonal boron nitride (h-BN)/rhenium diselenide (ReSe2) vdW heterojunction-based diode and studied the tunneling-based different phenomena, such as rectification, negative differential resistance (NDR) and backward rectification. Further, we measured a gate-tunable and tunneling-based rectifying current in BP/ReSe2 and BP/h-BN/ReSe2 heterojunction diodes, and achieved the highest tunneling-based rectification ratio of up to (RR ≈ 3.4 × 107). The high rectifying current is explained using the Simmons-based approximation through direct tunneling (DT) and Fowler–Nordheim tunneling (FNT) in low and high bias regimes. Furthermore, we extracted the photoresponsivity (R ≈ 12 mA W−1) and external quantum efficiency (EQE ≈ 2.79%) under an illuminated laser light source of wavelength 532 nm. Finally, we demonstrated the potential application of our heterostructure devices, such as a binary inverter, rectifier and switching operation at a high frequency. Our tunneling-based heterostructure device could operate at frequencies up to the GHz range. Therefore, our findings provide a new paragon to use the TMD-based vdW heterostructure in electronic and optoelectronic applications, such as multi-valued logic.