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

Nanogranular material systems are promisingfor a variety of applications in research and development.Their physical properties are often determined based on thegrain sizes, shapes, mutual distances, and chemistry of theembedding matrix. With focused-electron-beam-induceddeposition, arbitrarily shaped nanocomposite materials canbe designed, where metallic, nanogranular structures areembedded in a carbonaceous matrix. By using “post-growth”electron-beam curing, these materials can be tuned for animproved electric-transport or mechanical behavior. Such anoptimization necessitates a thorough understanding andcharacterization of the internal changes in chemistry andmorphology, which is where conventional two-dimensional imaging techniques fall short. We use scanning transmissionelectron tomography to obtain a comprehensive picture of the three-dimensional distribution and morphology of embedded Ptnanograins after initial fabrication and demonstrate the impact of electron-beam curing, which results in condensed regions ofinterconnected metal nanograins.