Stability of luminescent 3C-SiC nanocrystallites in aqueous solution

We study the long-term stability of luminescent suspended 3C-SiC nanocrystallites. Polycrystalline 3C-SiC wafers were electrochemically etched in HF-ethanol electrolyte and then ultrasonically treated in water to achieve spherical crystallites with diameters of 1-7 nm. The suspended 3C-SiC nanocrystallites exhibit tunable intense emissions which follow well the quantum size effect. After storage in air for over 7 months, partial larger 3C-SiC crystallites aggregate and form precipitates, while smaller ones remain uniformly dispersed in water and retain well luminescent properties. This characteristics makes small 3C-SiC crystallites excellent micro-emitters, which are especially useful in biological and medical applications. (c) 2006 Elsevier B.V. All rights reserved.