Identification of the reconstruction and bonding structure of SiC nanocrystal surface by infrared spectroscopy

We studied the surface structures of the cubic SiC nanocrystals by use of infrared spectroscopy. It was found that the Si–Si surface reconstruction occurs significantly in these nanocrystals. Besides, the oxygen bridge bond dominates their surface structure, which ensures the occurrence of ultra stable quantum-confinement photoluminescence. The larger crystallites exhibit much weaker infrared signals, but show longitudinal phonon mode that is absent in the small particles. The nanocrystals dispersed in lower-polarity solvent exhibit additional surface bonding structure other than that in water solvent.