Light at the Tip: Hybrid Scanning Tunneling/Optical Spectroscopy Microscopy
This review discusses the use of tunneling-induced light emission from nanoscale structures to characterize charge and energy transport and its application to solar energy conversion as well as light emitting structures. Several different mechanisms of tunneling induced luminescence have been observed with the most prevalent ones involving the formation of (radiative) surface plasmons induced by the tip of the scanning microscope. It is shown that the precise mechanism of the luminescence determines the spatial resolution of the technique, which in the most favourable cases can be submolecular or even atomic. Lastly, the addition of time-resolution to this technique is introduced.