Microscopic Raman study of graphene on 4H-SiC two-dimensionally enhanced by surface roughness and gold nanoparticles

We present microscopic Raman spectroscopy measurements on single-layer graphene epitaxially grown on 4H-SiC by a thermal decomposition method. We collected spectral data with spatial resolution, which allowed us to obtain two-dimensionally enhanced Raman mapping images. Shallow holes in SiC, which had areas of 5 to 20 µm and depths of 100 nm, enhanced the Raman intensity of the 2D band of graphene. A monolayer of gold nanoparticle (AuNP) aggregates was successfully prepared by dropping and drying a colloidal suspension of AuNPs. The AuNP exhibited 30-fold enhanced the Raman spectra in the wavenumber range of 1550–1700 cm−1. Locally enhanced Raman intensity was also demonstrated using a glass microbead.

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