Electrical transport properties of ZnO nanostructures

A physical vapour condensation method is used to synthesise the nanostructures of ZnO. These nanostructures are fabricated by resistive heating of Zn powder at a temperature of 400°C in the presence of oxygen and argon gases under a vacuum of order of 10- 6 mbar. The transmission electron microscope (TEM) images suggest that these nanostructures have some mixed morphology. They contain nanorods as well as nanoparticles. The typical diameter of these nanorods is in the range of 80 nm to 150 nm and the length is of the order of several hundreds of nanometers, whereas the size of the nanoparticles varies from 50 nm to 80 nm. Temperature dependence of dc conductivity of these ZnO nanostructures is also studied in the temperature range (303 K to 573 K). It is found that the experimental data gives a good fit for thermally activated process. Therefore, it is suggested that thermally activated process is responsible for the transport in these nanostructures.