Analysis and detection of low-energy electrons in scanning electron microscopes using a Bessel box electron energy analyser

Suri A., Pratt A., Tear S., Walker C., Kincal C., Kamber U., ...More

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, vol.241, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 241
  • Publication Date: 2020
  • Doi Number: 10.1016/j.elspec.2019.02.002


The interpretation of images generated by scanning electron microscopes (SEMs) requires quantifiable and well-understood contrast. Furthermore, recent interest in probing samples using low-energy electrons to extract surface information is pushing towards the quantification of relative contrast in secondary-electron (SE) images. The detection and analysis of low-energy SEs remains at the heart of the development of such instruments and techniques. However, state-of-the-art SE detectors in most SEMs, which are largely using in-lens configurations, are mainly designed to favour the collection of primary-induced SEs, and hence fail to provide electron energy information that could be related to the sample composition. Here, we report on the development of a novel SE detector which makes use of the Bessel box (BB) electron energy analyser. We demonstrate a very compact analyser design ((similar to)a volume of 12mm(3)) through simulations and by acquiring an electron spectrum from a sample of graphene on copper. A resolution of 0.3% has been numerically computed and experimentally verified for the BB analyser.