Electric Field Tunable Ultrafast Interlayer Charge Transfer in Graphene/WS2 Heterostructure

Abstract

Van der Waals heterostructures composed of two-dimensional materials offer an unprecedented control over their properties and have attracted tremendous research interest in various optoelectronic applications. Here, we study the photoinduced charge transfer in graphene/WS2 heterostructure by time-dependent density functional theory molecular dynamics. Our results show that holes transfer from graphene to WS2 two times faster than electrons, and the occurrence of interlayer charge transfer is found correlated with vibrational modes of graphene and WS2. It is further demonstrated that the carrier dynamics can be efficiently modulated by external electric fields. Detailed analysis confirms that the carrier transfer rate at heterointerface is governed by the coupling between donor and acceptor states, which is the result of the competition between interlayer and intralayer relaxation processes. Our study provides insights into the understanding of ultrafast interlayer charge transfer processes in heterostructures and broadens their future applications in photovoltaic devices.