Highly reproducible tip-enhanced Raman scattering using an oxidized and metallized silicon cantilever tip as a tool for everyone

We have successfully improved the reproducibility of tip-enhancement effect on metallized silicon cantilever tips for characterization of carbon nanotubes. Plasmon resonance tuning relative to an excitation wavelength is crucial for efficient tip-enhancement, which is accomplished by thermal oxidization and subsequent metallization of commercial silicon tips. Because of the change of the refractive index of the tip from silicon to silicon dioxide, the plasmon resonance of the silver-coated tip is blue-shifted showing an enormous enhancement at 532 nm excitation. Highly reproducible tips exhibit an enhancement factor of >100 with a 100% yield. Because the tips are fabricated from commercially available silicon cantilever tips in a simple and robust way, our approach provides an important step of 'tip-enhanced Raman spectroscopy for everyone'. Copyright (C) 2012 John Wiley & Sons, Ltd.