▎ 摘　　要

Optoelectronic properties of atomic thin van der Waals heterostructures (vdWHs) comprising transition metal dichalcogenides that harvest light energy are of paramount interest. In this work, the effects of underlying single- and bilayer graphene (Gr) layers on structural and physical properties of MoS2/Gr vertical heterostructures, i.e., (1-2L)MoS2/(1-2L)Gr, with additional interfaces including MoS2 folds/edges [MoS2(1L+1L))/Gr(1L)] and MoS2(1-2L)/Au, are investigated to unravel the excitonic properties. By employing correlative scanning probe microscopy combined with micro-spectroscopy, we observed multiple effects related to excitons (i.e., redshift of neutral excitons, ratio of charged excitons or trions to neutral exciton population, and long-tailed trions) and surface electronic properties (i.e., reduced work function suggesting electron transfer) in addition to significantly enhanced near-field Raman spectra, apparent n-p type current rectification behavior and increase in photogenerated carriers. All of these findings are attributed to interlayer electronic interactions while minimizing Fermi level pinning at the MoS2/Au interface, commonly observed in 2D semiconductor-3D metal junctions, which deepens our understanding of dissimilar 2D material junctions. Integrating MoS2 with an optimal number of graphene layers as a 'nanospacer' signifies substrate engineering that is versatile for key optoelectronic and photovoltaic applications.