Smart Materials & Structures

We have fabricated a two-dimensional MoS2/graphene van der Waals heterostructure substrate for surface-enhanced Raman spectroscopy (SERS). A stronger SERS enhancement was observed on the MoS2/graphene vdW heterostructure substrate compared to single-layer MoS2 or graphene substrate due to charge transfer and dipole-dipole interaction through the MoS2/graphene interface. Additionally, a novel substrate composed of gold nanoparticles (AuNPs) on MoS2/graphene vander Waals heterostructure was developed to explore the SERS eff ect of the AuNPs. Th e significant observed enhancement of this substrate can be attributed to the combination of the electromagnetic mechanism of plasmonic AuNPs and the muchenhanced chemical mechanism of the MoS2/graphene heterostructure via dipole-dipole interaction at the interface as compared to graphene only. The minimum detectable concentration of the R6G can reach 5x10-8M using a non-resonance 632.8 nm laser, which is an order of magnitude higher than that reported on the AuNPs/graphene substrate. SERS substrate based on MoS2/

graphene van der Waals heterostructure is an excellent SERS substrate for optoelectronics and biological detection.