Journal reference: Appl. Phys. Lett. 91, 063124 (2007)
Comments: Since v1: minor changes to text and figures to improve clarity; references added. Submitted to Applied Physics Letters, 30-Apr-07. 3 pages, 3 figures
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 silicon wafers with a certain thickness of silicon dioxide. We study graphene's visibility and show that it depends strongly on both thickness of silicon dioxide and light wavelength. We have found that by using monochromatic illumination, graphene can be isolated for any silicon dioxide thickness, albeit 300 nm (the current standard) and, especially, approx. 100 nm are most suitable for its visual detection. By using a Fresnel-law-based model, we quantitatively describe the experimental data without any fitting parameters.
@article{arxiv.0705.0259,
title = {Making graphene visible},
author = {P. Blake and K. S. Novoselov and A. H. Castro Neto and D. Jiang and R. Yang and T. J. Booth and A. K. Geim and E. W. Hill},
journal= {arXiv preprint arXiv:0705.0259},
year = {2007}
}