posted on 2023-10-12, 00:05authored byCynthia Cibaka-Ndaya, Kevin O’Connor, Emmanuel Opeyemi Idowu, Megan A. Parker, Eric Lebraud, Sabrina Lacomme, David Montero, Paula Sanz Camacho, Jonathan G.-C. Veinot, Ioan-Lucian Roiban, Glenna L. Drisko
Crystalline silicon
particles sustaining Mie resonances are readily
obtained from the thermal processing of hydrogen silsesquioxane (HSQ).
Here, the mechanisms involved in silicon particle formation and growth
from HSQ are investigated through real-time in situ analysis using an environmental transmission electron microscope
and X-ray diffractometer. The nucleation of Si nanodomains is observed
starting around 1000 °C. For the first time, a highly mobile
intermediate phase is experimentally observed, thus demonstrating
a previously unknown growth mechanism. At least two growth processes
occur simultaneously: the coalescence of small particles into larger
particles and growth mode by particle displacement through the matrix
toward the HSQ grain surface. Postsynthetic characterization by scanning
electron microscopy further supports the latter growth mechanism.
The gaseous environment employed during synthesis impacts particle
formation and growth under both in situ and ex situ conditions, impacting the particle yield and structural
homogeneity. Understanding the formation mechanisms of particles provides
promising pathways for reducing the energy cost of this synthetic
route.