Researchers from Imperial College London have demonstrated the possibility of obtaining TERS images with nanometre spatial resolution by using a commercially available upright microscope (top-illumination) and a gold-coated silicon AFM cantilever working in contact mode.

Mapping SWCNTs

They obtained images of single-walled carbon nanotubes (SWCNTs) with nanometre spatial resolution by using this approach. One of main obstacles for this type of TERS study is the shadowing and the background noise generated from the cantilever. The team overcame these difficulties by using an optical mask to create side-illumination and employing a "tip at the end of the cantilever" type AFM probe to minimize the shadowing effect.

The spatial resolution achieved with this system in an upright configuration was ~20–50 nm, which demonstrates the potential of this technique for studying non-transparent materials at the nanoscale without imposing limitations on samples.

The researchers presented their work in the journal Nanotechnology.