Filling the Gap: Atom Probe Tomography of Porous Structures Enabled by Site Specific SEMGlu Curing

Abstract

Porous microstructures, while central to many functional materials, remain difficult to characterize quantitatively by atom probe tomography (APT). Although several strategies have been proposed over the past decade, most remain constrained by significant practical or technical limitations. Here, we introduce an in situ pore filling approach that integrates seamlessly into conventional specimen preparation workflows. The method employs a vacuum compatible resin that is rapidly cured by the electron beam during standard ion beam based preparation, eliminating the need for additional instrumentation or extensive sample handling. We demonstrate the effectiveness of this approach using a porous SnSe + MXene electrode, a material system otherwise difficult to analyze via APT characterisation. This method offers a robust, accessible solution for extending APT analysis to porous materials

Figures (9)

• Figure 1: SEM images of SnSe electrode material showing a) a cross-section of the material with SnSe nanoparticles (light contrast) surrounded by MXene sheets (dark contrast), and b-d) APT specimens milled from the material, showing damage to the integrity of the specimens due to the porous structure
• Figure 2: SEM images of the glue filling process showing a) an SnSe lamella on a micromanipulator making contact with a blob of SEMGlu™, b) the glue creeping up onto the lamella and into the pores, and c) the coated lamella after part of the glue has been cured
• Figure 3: SEM images of an SnSe lamella showing a) the lamella prior to liftout with the micromanipulator, b) the lamella fully coated in cured glue, c) the outer layers of glue being milled away to reveal the lamella underneath, and d) the lamella with the pores now filled almost entirely with cured glue
• Figure 4: APT reconstruction of an SnSe specimen filled with glue, showing the locations of ions of C, H, Sn, and TiO, as well as the associated concentration heat maps. While the mechanical nature of the mixing process leads to some intermixing, but segregation can nonetheless be observed between the glue (H and C), the particles (Sn), and the Mxene structure (TiO)
• Figure S1: Mass-to-Charge spectrum of APT analysis shown in figure \ref{['fig:GlueNeedle']}