Structural and optical properties of ZnO nanosaws

The randomly oriented ZnO nanosaws were synthesized on Si substrates by a simple vapor transport method. For structure characterization of the products, the SEM micrograph clearly reveals that length of nanosaw exceeds several tens of μm and the side of sharp teeth of a saw has a length of about 1-5 μm and diameters of about 100 nm. The results of TEM, XRD, and Raman measurements indicate that the ZnO nanosaw is the single-crystal structure with the wurtzite phase. Under low excitation density, this UV emission peak measured at room temperature is attributed to the recombination of free excitons. Several sharp peaks emerge at photon energy around 3.18 eV with FWHM less than 4 meV when the sample is excited above a certain threshold. We refer that the random lasing in ZnO nanosaws results from the multiple coherent scattering in highly random-oriented ZnO nanosaws.