Laser Scanning Microscopy of Few-Layer Graphene: Optical Reflectivity Contrast*

We report laser scanning microscopy (LSM) of few-layer graphene, where a laser beam is raster scanned over the samples and the local reflectivity of the structure is directly measured through a silicon photodiode. The samples are grown by ambient-pressure chemical vapor deposition on copper foils, and transferred to SiO2/Si substrates, and consist of regions of single- and multi-layer graphene (D. R. Lenski, and M. S. Fuhrer, e-print arXiv: 1011.1683). While the local reflectivity of the structure depends on the thickness of the graphene layer, the LSM data is used to construct a two-dimensional reflectivity image of the sample which, in turn, enables identifying the local distribution of different graphene multilayers and local microscopic properties of the graphene sample.