Microplasma-induced surface engineering of silicon nanocrystals in colloidal dispersion

We report on an atmospheric-pressure dc microplasma that can be used to passivate silicon nanocrystals (SiNCs) in ethanol and that stabilizes their optoelectronic properties. We show that microplasma processing enhances the SiNCs photoluminescence intensity by factor of more than ten times and ∼80 nm redshift of its maximum. The microplasma induces the replacement of hydrogen terminations with hydroxyl-/organic-based bonds. The resulting surface characteristics are responsible for the formation of conductive and stable SiNCs self-organized assemblies extending over 0.5 mm after dewetting on a substrate.