Transmission Electron Microscopy Investigation of Self‐assembled 'Si/Mn 4 Si 7 ‐Alloy' Janus Nanosphere Architectures Produced by a HelixJet Atmospheric Plasma Source

The HelixJet atmospheric plasma‐assisted synthesis can be a new toolbox to realize dedicated nanoparticle architectures such as Janus‐type morphologies. Silicon nanoparticles produced by the decomposition of Silane molecules are directed into an in‐flight annealing stage. The applied high‐temperature supplies a metal vapor rich atmosphere containing Manganese, Chromium, Iron, and Tin outgassing from the used steel tube. The metal atoms alloy into the Silicon nanoparticles and form a self‐assembled 'Si/Mn x Si y ‐alloy' Janus nanosphere architecture. The Janus particles nanochemistry is thoroughly examined in detail by the analytic capabilities of transmission electron microscopy. The combined approach of electron diffraction, EDS, and EELS identifies the Janus particle composition consisting of a pure Si hemisphere interfaced to an alloyed Mn 4 Si 7 hemisphere covered by a thin (Mn a Fe b Cr c )Si y surface shell.