Melting and optical properties of ZnO nanorods

We observed that, by heating in air, the ZnO nanorods could start to melt at a temperature of similar to 750 degrees C, which is greatly reduced comparing with that of the bulk form. Prolonged annealing at this temperature resulted in partial melting of individual nanorods and the coalescence of the nanorods with their neighbors, leading to a great change in their optical properties, i.e., a new photoluminescence peak emerged at similar to 468 nm. Further analysis indicated that the new photoluminescence is closely related to the melting and the coalescence of the ZnO nanorods which probably induced some defects by thermal annealing at this temperature. (c) 2006 American Institute of Physics.