Analyzing the Nanogranularity of Focused-Electron-Beam-Induced-Deposited Materials by Electron Tomography

Nanogranular material systems are promising for a variety of applications in research and development. Their physical properties are often determined based on the grain sizes, shapes, mutual distances, and chemistry of the embedding matrix. With focused-electron-beam-induced deposition, arbitrarily shaped nanocomposite materials can be designed, where metallic, nanogranular structures are embedded in a carbonaceous matrix. By using “post-growth” electron-beam curing, these materials can be tuned for an improved electric-transport or mechanical behavior. Such an optimization necessitates a thorough understanding and characterization of the internal changes in chemistry and morphology, which is where conventional two-dimensional imaging techniques fall short. We use scanning transmission electron tomography to obtain a comprehensive picture of the three-dimensional distribution and morphology of embedded Pt nanograins after initial fabrication and demonstrate the impact of electron-beam curing, which results in condensed regions of interconnected metal nanograins.