The red and blue luminescence in silicon nanocrystals with oxidized, nitrogen-containing shell
Traditionally, two classes of silicon nanocrystals (SiNCs) are recognized with respect to their light-emission properties. These are usually referred to as the "red" and the "blue" emitting SiNCs, based on the spectral region in which the larger part of their luminescence is concentrated to. The origin of the "blue" luminescence is still disputed and is very probably different in different systems. One of important contributions to the discussion about the origin of the "blue" luminescence was the finding that the exposure of SiNCs to even trace amounts of nitrogen in the presence of oxygen induces the "blue"' emission, even in originally "red"-emitting SiNCs. Here, we obtained a different result. We show that the treatment of "red" emitting, already oxidized SiNCs in water-based environment containing air-related radicals including nitrogen-containing species as well as oxygen diminishes, rather than induces the "blue" luminescence.