Electrical conductivity of sol-gel derived metal nanoparticles

Electrically conducting films of thickness 2 μm have been prepared on ordinary glass slides by growing ultra-fine particles of iron and copper, respectively, from a suitable precursor sol. The diameters of metal particles can be varied from 3-13 nm by controlling the heat-treatment schedule of the sol coating. Resistivity measurements (d.c.) have been carried out over the temperature range 80-300 K. The resistivity values in the range 0.0001-0.0039 cm have been obtained depending on the particle diameter and the type of metal used. The effective Debye temperature D for the different nanoparticle systems have been estimated by fitting the experimental data to the Ziman equation. D is found to vary from 346-408 K for iron with the particle size in the range 3.4-9.5 nm. The values obtained for copper are 243-307 K with particle diameters covering a range of 5.9-12.6 nm