Low-energy-filtered secondary-electron emission microspectroscopy using a cylindrical mirror analyzer.

The local work function, surface potential, charging/discharging behavior, and elemental/chemical properties are among the information conveyed by the energy spectra of secondary electrons (SE) emitted by electron impact from materials. In this contribution, we present SE emission spectroscopy (SEES) from different material surfaces. The samples are locally excited by a microscope electron beam, and the spectra are collected using a cylindrical mirror analyzer (CMA). The line shape profile and the onset of the spectra are studied as a function of the sample orientation, primary-beam energy, and sample bias. The CMA transmission, showing a low-energy cutoff at about $15 {eV}$, is efficiently adapted to investigate the SE range (0 to $50 {eV}$) by applying proper bias voltages in a tilted primary-beam incidence geometry. We also discuss the spectral shape evolution as a function of sample bias in terms of SE emission physics and instrumental artifacts. In perspective, SEES can pave the way for nanoscale hyperspectral and time-resolved electron microscopy investigation of surface phenomena like catalysis, phase transitions, and collective dynamics ($e.g.$, plasmons and phonons).