Growth of CdS nanowires using Na-4 mica as template

Sodium flourophlogopite mica of composition ${\mathrm{Na}}_4{\mathrm{Mg}}_6{\mathrm{Al}}_4{\mathrm{Si}}_4{\mathrm{O}}_{20}{\mathrm{F}}_4\mathrm{\cdot x }{\mathrm{H}}_2\mathrm{O}$ (referred to as Na-4 mica) was prepared by a sol–gel technique. CdS nanowires of 1.2 nm thickness were grown by using the nanochannels within the mica structure. Optical absorption spectra showed peaks at 350 and 504 nm, respectively. These are ascribed to the presence of CdS nanoclusters of diameter ∼1.21 nm and CdS wires of length ∼100 nm, respectively. The nanowires exhibited a photoluminescent peak at 2.37 eV arising due to excitons. The dielectric constant of the nanocomposite was found to be much larger (∼95) than that of the base material (∼17). This has been explained on the basis of a simple stacking of nanoscale capacitors within each grain of Na-4 mica.