1 Laboratoire de Physique des Interfaces et des Couches Minces, CNRS, École Polytechnique, IP Paris, 91128 Palaiseau, France.
2 LMF, École Normale Supérieure, Paris-Saclay, 91190 Gif-sur-Yvette, France.
3 CRHEA, CNRS, Université Côte d'Azur, 06903 Sophia-Antipolis, France.
4 Center for SiNC Applications, 75000 Paris, France.
5 Centre for Research in Molecular Modeling, Concordia University, Montreal, QC H4B 1R6, Canada.

The outstanding properties of silicon nanoparticles have been extensively investigated during the last few decades. Experimental evidence and applications of their theoretically predicted permanent electric dipole moment, however, have only been reported for silicon nanoclusters (SiNCs) for a size of about one to two nanometers. Here, we have explored the question of whether suitable plasma conditions could lead to much larger silicon clusters with significantly stronger permanent electric dipole moments. A pulsed plasma approach was used for SiNC production and surface deposition. The absorption spectra of the deposited SiNCs were recorded using enhanced darkfield hyperspectral microscopy and compared to time-dependent DFT calculations. Atomic force microscopy and transmission electron microscopy observations completed our study, showing that one-to-two-nanometer SiNCs can, indeed, be used to assemble much larger "superclusters" with a size of tens of nanometers. These superclusters possess extremely high permanent electric dipole moments that can be exploited to orient and guide these clusters with external electric fields, opening the path to the controlled architecture of silicon nanostructures.