Luminescent silicon carbide nanocrystallites in 3C-SiC∕polystyrene films

Abstract

We report optical emission of SiC nanocrystallite films, which clearly shows the quantum confinement effect. Bulk polycrystalline 3C-SiC was first electrochemically etched and then the fabricated porous silicon carbide was ultrasonically treated in water or toluene suspension to disperse into colloidal nanoparticles. Transmission electron microscopy images clearly show that the colloidal nanoparticles have 3C-SiC lattice structure with sizes varying from about 6nm down to below 1nm. The suspension of 3C-SiC nanocrystallites exhibits ultrabright emission with wavelengths ranging from 400to520nm when the excitation wavelength varies from 250to480nm, in accordance with the quantum confinement effect. By adding polystyrene to the toluene suspension containing SiC nanoparticles and coating the mixing solution onto a Si wafer, we obtain the SiC∕polystyrene films that luminesce.

Influence of Y2O3 addition on electrical properties of β-SiC ceramics sintered in nitrogen atmosphere

“…These emission structures, peaked at about 2.35, 2.50, 2.75, and 2.90 eV, look similar to those reported for nanocrystalline 3C-SiC samples 24,34. Thus, the new emission structures from the Y 2 O 3 -doped SiC samples are likely to originate from SiC grains rather than Y 2 O 3 clusters.…”

Effective passivation on Si nanocrystal surface by peroxide

“…This means that water does not provide new defects that can change the red PL band, and it can be an indirect evidence to support the conclusion that Si-H x (x ¼ 1, 2) bonds and Si¼O bonds are the origin of the broad red PL band. Water is a kind of effective solvent, because it can keep individual Si nanocrystals apart and provide a high potential barrier for carriers (electrons and holes) [11,12]. Moreover, little difference between the PL and PLE spectra of the as-made PS and Si nanocrystal suspension demonstrates that the surrounding water has little influence on luminescence property of the Si nanocrystals.…”

“…Thus, dispersion of the material into ultrasmall particles allows the isolation of single particle effects and opens the way for direct examination of quantum confine theory [10]. To achieve uniform distribution, Si nanocrystals crumbled from PS are usually mixed into a polar solvent such as water [11,12].…”

Low-dimensional SiC nanostructures: Fabrication, luminescence, and electrical properties

“…These 3C-SiC nanocrystals that exhibit wavelength-tunable and strong luminescence have potential applications in nano-optoelectronics and biology/medicine [35]. As an extension of this technique, SiC/polymer composite films emitting blue light have also been synthesized successfully [36].…”