title: Spatial modulation spectroscopy of graphene sheets.
abstract: Two different samples of graphene, multi-layer flakes on Si/SiO2 substrates and single layer graphene on glass, have been examined by reflectivity contrast and spatial modulation spectroscopy measurements. For the multi-layer graphene flakes, the reflectivity contrast and spatial modulation spectroscopy measurements are in good agreement, validating the application of spatial modulation spectroscopy to two-dimensional samples. The measurements for single layer graphene on glass show features that correspond to increases and decreases in reflectivity. The features with increased reflectivity are assigned to small regions of multilayer graphene or polymer, and the features with decreased reflectivity are assigned to holes in the graphene film. Using a model for thin film reflectivity we calculate the size dependent spatial modulation signal for the holes, and find that a significant number of holes have a larger than expected signal. This could arise from the presence of multi-layers of graphene in the sample, or because of optical resonance effects for the holes.
authors.affiliation: Ecole Normale Supérieure de Lyon, 15 Parvis René Descartes, 69342 Lyon Cedex 07, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Havard
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
authors.forename: Vaishnav
authors.initials: V
authors.lastname: Murthy
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
authors.forename: Shun Shang
authors.initials: SS
authors.lastname: Lo
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Hartland