Tip enhanced Raman spectroscopy of carbon nanomaterials

Abstract

We have successfully optimized tip-enhancement effect at metallized silicon cantilever tips for characterization of carbon nanomaterials such as single walled carbon nanotube and graphene layers. Plasmon resonance tuning relative to an excitation wavelength is crucial for efficient tip-enhancement, which is done by thermal oxidization of the silicon tips. Owing to the change of the refractive index, the plasmon resonance of the coated silver is blue-shifted showing an enormous enhancement at 532nm excitation. We demonstrate tip-enhanced Raman spectroscopy on carbon nanomaterials that show constantly exhibit an enhancement factor of >100.