Scanning probe energy loss spectroscopy

This article gives a status report on the new technique of scanning probe energy loss spectroscopy (SPELS), which can be viewed as a hybrid between scanning tunnelling microscopy and electron energy loss spectroscopy. The technique provides local energy loss spectra from solid surfaces (at room temperature) with an expected spatial resolution of 1–10 nm and a current best energy resolution of 0.6 eV. Spectra are presented from the graphite and Si(1 1 1)-7×7 surfaces as well as metallic (silver and gold) thin films, which enables the chemical analysis capabilities of the technique to be demonstrated. New and future developments are also discussed, including the demonstration of SPELS with screened tips and the prospects for spectral measurements with energy resolution in the vibrational regime.