Hydrogenated Silicon Nanoclusters with a Permanent Electric Dipole Moment for the Controlled Assembly of Silicon-Based Nanostructures

While silicon nanoclusters have extensively been used for their outstanding properties for many decades, never before has their dipole moment been exploited for any application. Here, we have succeeded in producing hydrogenated silicon nanoclusters with a strong permanent electric dipole moment. This dipole moment allows us to use electric fields in order to orient and guide individual clusters. As a first example, we demonstrate the catalyst-free one-by-one self-assembly of one of the thinnest silicon nanowires yet observed. As a second example, we show that the simple presence of those nanoclusters on LaB6 cathodes leads to a 30-fold enhancement of the thermionic electron current density over pristine LaB6. Last but not least, the nanoclusters provide a protective layer against chemical and mechanical attack and largely prevent the evaporation of substrate materials, potentially increasing the operational lifetime of cathodes substantially.