Local structural and optical properties of ZnO nanoparticles.

This study examined the local structural and optical properties of ZnO nanoparticles (NPs) with mean diameters of 4.5 and 70 nm using extended X-ray absorption fine structure (EXAFS) measurements at the Zn K edge and photoluminescence (PL) measurements. EXAFS revealed that the average bond length of atomic pairs in the NPs was shorter than that of the powder. Furthermore, a substantial amount of structural disorder existed in the NPs. From the PL measurements, we observed the direct band gap peak of 3.41 eV from the 70 nm ZnO NPs at low temperatures. This blue shift was related to the structural property changes.