TERS on Single-crystalline Surfaces

This means that one needs tips free of adsorbates and contamination, and very smooth surfaces, which cannot support SERS. Well-annealed single-crystalline metal surfaces are suitable substrates in this respect. An easy way to prepare such crystals is to use the flame-annealing technique developed by Clavilier [147]. This simple procedure not only removes contamination, but also produces very smooth surfaces. These smooth surfaces are not SERS active in the usual sense. 

Please note that in the TERS experiments, the tip adsorbate-metal configuration is operated in air (not under UHV conditions) after the adsorption of the 

3) To our knowledge, up to today no other group 4) Howevei if sensitivity is die major point, a has reported TERS from single crystalline sur- combination of TERS and SERS may be of faces. great advantage [143]. 

In fact, when the Au tip is brought into the tunnehng position, two spectacular effects are observed a huge enhancement for Raman scattering and a very rapid photobleaching. The strongest Raman peak intensities rise from 1-2 cps to 

Rf 1000 nm, the radius of the area of the sample probed by TERS results in a 90 nm. This estimate does not depend much on the local field distribution a Gaussian or a Lorentzian profile would also yield the above equation for a apart from a somewhat altered prefactor. The actual tip radius of 40 nm, determined by SEM for the tip used in this experiment, comes close to the above estimate. 

---