Visibility and Raman spectroscopy of mono and bilayer graphene on crystalline silicon

摘要

Experimental studies of pristine graphene devices currently rely on the fact that the graphene crystallites can be visible under optical microscopes when the underlying substrate is engineered to exhibit high contrast. Here, we present that graphene can be visualized not only on a dielectric substrate but also on a crystalline Si surface of a silicon-on-insulator (SOI) wafer (SIMOX and Bonded) with thicknesses of Si ～70 nm and buried oxide ～140 nm, using monochromatic illumination. In addition, we have found that Raman spectroscopy shows similar features to standard graphene on SiO_2 substrates independent of the polarity of the Si surface. Finally, the Raman spectrum on SOI exhibits a higher intensity compared to that on bulk Si due to the interference enhancement effect of graphene on SOI. Thus, the usage of optical microscopy and Raman spectroscopy for detecting, locating, and characterizing graphene serves as a high throughput method to further study graphene on semiconductor systems and other substrates beyond SiO_2/Si.