Statistical Coulomb interactions in multi-beam SEM

Statistical Coulomb interactions in conventional scanning electron microscopy mostly affect the probe size via energy spread and virtual source broadening in the emitter vicinity. However, in a multi-beam probe forming system such as a multi-beam scanning electron microscopes (MBSEM), the trajectory displacement due to interactions in the...

Observation of Electron Coherence and Fabry-Perot Standing Waves at a Graphene Edge

Electron surface states in solids are typically confined to the outermost atomic layers and, due to surface disorder, have negligible impact on electronic transport. Here, we demonstrate a very different behavior for surface states in graphene. We probe the wavelike character of these states by Fabry-Perot (FP) interferometry and find that,...

Electron optics of skewed micro-Einzel lenses

Micro-Einzel lenses always suffer from chromatic and spherical aberration, even when the electron beam is exactly on the optical axis of the lens. When the inclination of the electron beam with respect to the lens axis increases, additional effects such as coma, astigmatism, and defocus start to dominate. An example of inclined electron beams in...

Electron optics of microlenses with inclined beams

For multielectron beam systems with a single electron source, the outside beams need to be collimated before entering the individual microcolumns. As an alternative of the traditional multibeam source design where the broad beam from the source is collimated by a single lens, the broad beam can be first split in subbeams that are focused by a...

Low-energy electron beams through ultra-thin foils, applications for electron microscopy

This thesis has discussed two electron microscopy applications that make use of ultra-thin foils: the tunnel junction emitter and the low-energy foil corrector. Both applications have in common that the electron beam is sent through the thin foil at low energy. Part of the electrons will scatter in the foil, thus causing a reduction of the...