Highly Efficient Silicon Photonic Microheater Based on Black Arsenic–Phosphorus

While black phosphorus has shown excellent optoelectronic properties in many aspects, the environmental instability ultimately places limits on its practical applications. Black arsenic–phosphorus (b-AsP), an alloy of black phosphorus with arsenic atoms, has emerged as a new 2D material with better stability. Recently, the heterostructure via integration of 2D material with nanophotonic waveguides is opening an avenue for many on-chip applications of phosphorene. However, the thermo-optic (TO) properties, which are widely used for waveguide heaters, are not studied on b-AsP yet. Herein, the TO effects of a b-AsP/silicon van der Waals heterostructure are first investigated and its application as a transparent waveguide heater is demonstrated. A high efficiency of 0.74 nm mW⁻¹ is achieved with a nonresonant and broadband heater based on 20 nm thick b-AsP, which eliminates the need for enhancement by cavity-assisted light–matter interaction, and thus allows for compact footprint, broadband operation, and low latency.