Interfacial Charge Transfer for Enhancing Nonlinear Saturable Absorption in WS2/graphene Heterostructure

Interlayer charge‐transfer (CT) in 2D atomically thin vertical stacks heterostructures offers an unparalleled new approach to regulation of device performance in optoelectronic and photonics applications. Despite the fact that the saturable absorption (SA) in 2D heterostructures involves highly efficient optical modulation in the space and time domain, the lack of explicit SA regulation mechanism at the nanoscale prevents this feature from realizing nanophotonic modulation. Here, the enhancement of SA response via CT in WS2/graphene vertical heterostructure is proposed and the related mechanism is demonstrated through simulations and experiments. Leveraging this mechanism, CT‐induced SA enhancement can be expanded to a wide range of nonlinear optical modulation applications for 2D materials. The results suggest that CT between 2D heterostructures enables efficient nonlinear optical response regulation. Saturable absorption modulation of 2D heterostructures is an important issue in the field of nonlinear optics of 2D materials. In this work, the mechanism of interfacial carrier transfer modulation on saturable absorption response by experimental and simulation methods are designed and verified, which provides guidance for the application of 2D materials in all‐optical and optoelectronic devices.