Novel nanoscale probing techniques are developed by combining Scanning Probe Microscopy (SPM) and the near optical field created around the SPM probe by ultra-short pulse laser illumination. The latter enables single and multi-photon electronic excitation processes to occur and to be mapped by SPM. It also provides nanoscale processing capabilities by highly localized laser-induced structural modifications of solids, ablation and molecule dissociation as in photo-CVD.
These techniques have been implemented for the study of electron emission from nanostructures and nanoscale areas on solid surfaces with results which are both of great interest for the particular systems studied but also very promising with regards to much wider applicability.
Electron emission from metals and semiconductors, including wide gap oxides and nitrides, depends strongly on the geometry and length scale of the emitting structures as well as on surface contamination and chemical alteration. The above mentioned techniques are a tool of choice in the study of these effects which are of great interest to many applications.
We use Conductive Atomic Force Microscopy (CAFM) in dark and laser-induced current mapping as the mechanical AFM feedback mechanism allows for precision tracing of the surface studied, regardless on the electric current flowing between the sample and a conducting AFM tip, in any environment: air, controlled atmosphere or vacuum.