Raman spectroscopy was also employed to characterize
the synthesized sample. The Raman spectra were obtained
by a micro-Raman setup equipped with Rayleigh scattering
micro imaging. The setup is made up of a Coherent Sabre
Ar+ laser, a Dilor triple monochromator equipped with LN2
cooled CCD (Horiba 3000C), confocal optics and a nanometric
piezo actuated positioning/scanning table. The confocal optics
allows a spatial resolution of 350 nm in the xy plane
and of 1 lm along the z-axis. The spectra was acquired
using an exciting laser wavelength of 514 nm in the backscattering
configuration z(x,x)-z