Exploring the Interface Landscape of Noble Metals on Epitaxial Graphene

摘要

Understanding the interaction between noble metals (NMs) and epitaxial grapheneis essential for the design and fabrication of novel devices. Within thisframework, a combined experimental and theoretical investigation of the effect ofvapor-deposited NM (silver [Ag] and gold [Au]) nanostructures on the vibrationaland electronic properties of monolayer epitaxial graphene (MLG) on 4H-SiC ispresented. Large sets of Raman scattering data are analyzed using supervisedclassification and statistical methods. This analysis enables identification of thespecific Raman fingerprints of Au- and Ag-decorated MLG originating fromdifferent dispersion interactions and charge transfer at the metal nanostructure/MLG interface. It is found that Raman scattering spectra of Au-decorated MLGfeature a set of allowed phonon modes similar to those in pristine MLG, whereasthe stronger Ag physisorption triggers an activation of defect-related phononmodes and electron doping of MLG. A principal component analysis (PCA) andlinear discriminant analysis (LDA) are leveraged to highlight the features inphonon dispersion of MLG that emanate from the NM deposition process and torobustly classify large-scale Raman spectra of metal-decorated graphene. Thepresent results can be advantageous for designing highly selective sensor arrayson MLG patches decorated with different metals.