Nanoscale spectroscopic mapping by scanning probe electron energy spectroscopy

Scanning probe electron energy spectroscopy (SPEES) is a developing technique capable of both topographic and spectroscopic mapping of the surface. Here we report a SPEES study for Ag nanostructures on graphite with a microelectrode-shielding tip. The spatial distributions of electron energy loss spectra as well as secondary-electron emission spectra in the same region on the surface are measured. The spatial resolution is determined to be about 17 nm. This demonstrates the nanoscale spectroscopic mapping ability of the SPEES and a promising tool for investigating highly-localized object on surface and related phenomena, such as plasmonic substrates, nonlinear electron scattering, etc.