Monte Carlo SEM-EDS micro- and nanoanalysis of ultrathin gold leaves in glass mosaic tesserae: Thickness effects and measurement strategy

Scanning Electron Microscopy (SEM) coupled to Energy Dispersive X-ray Spectrometry (EDS) is a very effective methodology to investigate the local composition of ultrathin materials, such as metal leaves in glass mosaic tesserae. However, a careful analytical strategy must be considered when dealing with this type of investigations, because the metal leaf is extremely thin, typically 0.2–1 μm. Many artefacts could arise from the electron and X-ray scattering in the thin metal leaf and adjacent glass layers and from EDS detector – sample configurations and arrangements. In this work, Monte Carlo simulation was used to study the effects related to the metal leaf thickness, tessera composition, SEM-EDS setup and detector physics, in order to understand the limits of the methodology. A general micro-nanoanalytical strategy for accurate SEM-EDS quantitative analysis is provided to the interested reader, also useful for other ultrathin layers, substrates, composites, powder materials and micro – nanosized specimens.