High spatial resolution ellipsometer for characterization of epitaxial graphene.

An ellipsometer with 3µm×5µm spot size constructed with a single focusing and imaging element is used to measure the layer number of exfoliated graphene on glass and expitaxial graphene on SiC. Ellipsometric sensitivity to graphene layer number increases with decreasing layer number and decreasing substrate refractive index. Single-atomic-layer sensitivity has been achieved. High spatial resolution imaging and ellipsometry is useful for rapid characterization of epitaxially grown graphene films.