  Nanostructured Zinc oxide (ZnO) was synthesized via a ball milling for 10
hours using high energy planetary ball mill. Phase purity and homogeneity of
all the samples have been investigated by X-ray diffraction (XRD) and Field
Emission Scanning Electron Microscopy (FE-SEM). All the diffraction peaks can
be indexed to the hexagonal phase ZnO with hexagonal symmetry (space group
P63mc). Average crystallite size was observed to be 20 nm. There was a
remarkable suppression in thermal conductivity ({\kappa}) compared to the bulk
values by a factor of ~50 at room temperature. This suggests to the possibility
of using nanostructured ZnO as a prospective room temperature thermoelectric
material.
