Photoinduced Electron Transfer at the Interface between Heterogeneous Two-Dimensional Layered Materials

Abstract

We study the optical response of a MoS2–graphene heterostructure by carrying out first-principles calculations of electron dynamics in real time and real space. Our attention is primarily focused on the effect of interfacial contact between MoS2 and graphene. The interfacial contact has a negligible influence on the optical absorption of the MoS2–graphene heterostructure. However, the photoinduced electron dynamics of the heterostructure is crucially different from those of the isolated monolayers of MoS2 and graphene; electronic polarization perpendicular to the MoS2–graphene interface is induced by a laser pulse polarized parallel to the interface. By analyzing the variation in the electron occupation number, we find that electronic transitions in graphene and MoS2 accompany the electron transfer from graphene to MoS2. This is due to the difference in the magnitudes of the density of states of MoS2 and graphene. In other words, the photoinduced electron transfer is governed by the details of the electro...