Au Nanoparticles/WS2 Nanodomes/Graphene van der Waals Heterostructure Substrates for Surface-Enhanced Raman Spectroscopy

This work explores superposition of the localized surface plasmonic resonance (LSPR) effect of Au nanoparticles (AuNPs) with that on transition metal dichalcogenide (TMD) WS2 nanodomes (WS2-NDs) enabled by enhanced dipole-dipole interaction at van der Waals (vdW) interfaces in AuNPs/WS2-NDs/graphene heterostructures for surface-enhanced Raman spectroscopy (SERS) with high-sensitivity, The confirmation of such a superposition is first demonstrated in the enhanced graphene Raman signatures, such as the G-peak intensity by approximately 7.8 fold on the AuNPs/WS2-NDs/graphene over that of reference graphene sample, in contrast to 4.0 and 5.3 folds respectively on AuNPs/graphene and on WS2-NDs/graphene. Furthermore, Raman spectra of probe molecules of fluorescent Rhodamine 6G (R6G) were hired to quantify the enhanced SERS on AuNPs/WS2-NDs/graphene SERS substrates. At the R6G concentration of 5x10-5 M, enhancement factors of ~ 2.0 and 2.4 based on the R6G 613 cm-1 peak intensity are detected on the AuNPs/WS2-ND...