Local structural properties of ZnO nanoparticles, nanorods and powder studied by extended X-ray absorption fine structure

We investigated the local structural properties of ZnO nanoparticles (NPs), nanorods and powder by using extended X-ray absorption fine structure (EXAFS). The average diameter and size of the ZnO NPs and nanorods were about 4.5 nm and 40 nm, respectively. The EXAFS analysis revealed that the bonding lengths of atoms in the ZnO nanorods were slightly elongated along the c-axis while they were shrunken in the aft-plane, as compared with those of the ZnO powder. We did not observe a vacancy or an extra disorder for the ZnO nanorods with an average length of 0.5 μm. However, there were about 30 % vacancies in the oxygen and the zinc site of the ZnO NPs and the Zn-Zn bonding length had a substantial amount of disorders. ZnO NPs had a distorted-wurtzite structure with the same bonding length of four Zn-0 pairs. The vacancy, the disorders and the distortion should be counted if the changes in the properties of the ZnO NPs are to be understood.