to the vibrations of TO (∼796 cm−1) and LO (∼972 cm−1) phonon
modes of cubic SiC [18]. From the figure, it is easy to find that the
two shifts are widened evidently contrasted to bulk 3C–SiC and
this result indicates that the as-grown SiC nanoparticles might be
in very small grain sizes or large quantities of crystal defects and
serious lattice distortion have been formed in the particles [19].
Room-temperature PL of SiC/Si-NPA was studied by us. Excited
by 300 nm ultraviolet fluorescent light at room temperature, the PL
spectra of SiC/Si-NPA and the annealed Si-NPA which was treated
at 1000 ◦C in pure Ar gas were obtained and presented in Fig. 3. It
can be observed that no light emitted from the annealed Si-NPA
while strong light emissions peaked at 383 nm, 402 nm and 420 nm
are obtained in SiC/Si-NPA. This result illustrates that the strong
UV-blue light emissions come from the 3C–SiC film. The dominant
light emission peaked at 402 nm is ascribed to the lattice defects in
3C–SiC nanocrystals by referring to a new report of Kim’s [20] who
owed a strong emission of 2.75 eV in nanocrystalline SiC to the
defects in the nanoparticles. XRD and Raman data measured from
SiC/Si-NPA have proved that the prepared 3C–SiC particles contain
a large number of crystal defects which would be the origin of
the violet light emission. The UV light emission peaked at 383 nm
might come from some multiple stacking faults in the 3C–SiC film
[21]. As to the blue light emission peaked at 420 nm, it is related
to the quantum confinement effect (QCE) in SiC nanocrystals by us
since QCE has been found in colloidal 3C–SiC nanocrystals [22,23],
close-packed SiC nanocrystal films [24] and some 3C–SiC films