Realizing the Switching of Optoelectronic Memory and Ultrafast Detector in Functionalized-Black Phosphorus/MoS₂ Heterojunction

A single device with switchable functions is highly attractive to the growing demands of complex optoelectronics. However, most of the currently reported devices either exhibit a lack of multifunction operation or require complex electrode configurations with limited performances. Here, a new concept of a functionalized-black phosphorus (f-BP)/MoS₂ heterojunction is proposed, which enables the coexistence of an optoelectronic memory and a detector in a single device. The oxidation-induced artificial-traps on the BP surface result in a gate-modulated photogating effect, so that the device can be freely switched between memory and detector by simply changing the back-gate voltage. In the memory model, the device has an ultra-long storage time (10 years), an ultra-high on/off ratio (3.5 × 10⁷), and outstanding multi-bit storage (≈90 states), while in the detector model, the device still exhibits a fast response (130/260 µs), an impressive responsivity (22.2 A W⁻¹), and self-driven broadband detection (ultraviolet to near-infrared). Most importantly, the highly anisotropic BP enables fast NIR polarization resolution with a maximum polarization ratio of 6.98 at 1064 nm.