Realizing the Switching of Optoelectronic Memory and Ultrafast Detector in Functionalized‐Black Phosphorus/MoS 2 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)/MoS 2 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 × 10 7 ), 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.