cfaed Seminar Series

143 years ago Ernst Abbe discovered that it is impossible to resolve surface features having size below the diffraction limit using an optical microscopes. Today, we have a range of analytical techniques that have successfully overcome the diffraction barrier allowing visualisation of surface chemistry and molecular phenomenon with a nanoscale resolution. In this talk, I would introduce a powerful super-resolution imaging technique called tip-enhanced Raman spectroscopy (TERS) in which the diffraction limit is overcome using light interaction with metal nanostructures, AKA plasmonics. TERS involves a combination of Raman spectroscopy with Scanning Probe Microscopy (SPM), enabling simultaneous mapping of surface chemical composition and topography at the nanoscale. I would demonstrate the application of this powerful technique with three case studies:

1. Mapping of heterogeneous catalytic reactions at the nanoscale¹
2. Visualisation and characterisation of nanoscale defects in Graphene and 2D materials^2-4
3. Simultaneous topography, electrical and optical microscopy of optoelectronic devices at the nanoscale⁵

Finally, I would discuss the metrology challenges of this emerging technique and the recent progress made in TERS metrology at NPL.