Material-specific mapping of metal/semiconductor/dielectric nanosystems at 10 nm resolution by backscattering near-field optical microscopy
R. Hillenbrand and F. Keilmann
Applied Physical Letters 80, 25 (2002)
We report that three main constituents of nanosystems—metals, semiconductors, and dielectrics—can be categorically distinguished by their specific optical near-field contrast at 633 nm wavelength. The decisive property is the local dielectric constant as we show by calculations based on dipolar coupling theory. Experiments with Au/Si/PS(polystyrene) nanostructures using an apertureless scattering-type near-field optical microscope yield optical images at 10 nm resolution, with clear material contrast close to predicted levels.