Scanning probe energy loss spectroscopy below 50 nm resolution

We report scanning probe energy loss spectroscopy (SPELS) measurements from a roughened Si(111) surface in ultrahigh vacuum. The experiments, which utilize a scanning tunneling microscope tip in the field emission mode as the electron source, establish that the spatial resolution in SPELS is better than 50 nm. The spectral maps acquired indicate different contrast mechanisms for the inelastically scattered and secondary electrons identified in the energy loss spectrum. (C) 2004 American Institute of Physics.