Two dimensional heterostructure： perfect platform for exploring interface interaction

Two-dimensional （2D） materials have been attracting great amount of attentions from researchers worldwide due to their exo- tic mechanical, optical, electrical, thermal and catalytic properties, which could enable their potential applications in future multi- functional devices. The interests in 2D materials were initially inspired by the successful exfoliation and characterization of monolayer graphene in 2004 [1 ]. However, the absence of a band gap in graphene limits its use in many logic electronic devices. The demonstration of semiconducting monolayer molybdenum disulfide based field-effect transistors [2], along with the success- ful preparation of other monolayer transition metal dichalco- genides by various methods [3-7], provide new possibilities of creating novel devices with additional functionalities.