Controllable Photocurrent Generation in Lateral Bilayer MoS₂-WS₂ Heterostructure

Laterally epitaxial two-dimensional (2D) transition metal dichalcogenides (TMDs) heterojunctions are of considerable interest in recent years due to atomically sharp interfaces and tunable band alignment, which have potential applications in novel functional electronics and optoelectronics. However, the studies of 2D lateral heterostructures have mainly focused on the synthesis methods and pristine performance of the fabricated heterojunctions. Herein, the controllable photocurrent generation and enhanced performances of the lateral bilayer (LBL) MoS2-WS2 heterojunctions are reported. A tunable and abrupt built-in field forms at the interface, and the gate-tunable rectifying behavior and photovoltaic effect are realized. It is demonstrated that the generation of the photocurrent in the device can be highly controlled to realize ultrahigh responsivity of 1.06 x 10(4) A W-1 and detectivity of 1.14 x 10(13) Jones at a 638 nm incident light. The lateral TMDs heterostructures are expected to constitute the ultimate functional elements of novel electronics and optoelectronics.