Making graphene visible

Abstract

Microfabrication of graphene devices used in many experimental studies currently relies on the fact that graphene crystallites can be visualized using optical microscopy if prepared on top of Si wafers with a certain thickness of Si O2. The authors study graphene's visibility and show that it depends strongly on both thickness of Si O2 and light wavelength. They have found that by using monochromatic illumination, graphene can be isolated for any Si O2 thickness, albeit 300 nm (the current standard) and, especially, ≈100 nm are most suitable for its visual detection. By using a Fresnel-law-based model, they quantitatively describe the experimental data. © 2007 American Institute of Physics.