Raman scattering of single tetrapod-like ZnO nanostructure synthesized by catalyst-free rapid evaporation

The x-y spatially-resolved mappings of polarized Raman scattering spectra from a single tetrapod-like ZnO nanostructure were proposed and performed with different polarized scattering configurations by utilizing the intrinsic geometry configuration. The ZnO nanostructures were synthesized by rapid thermal evaporation of metal zinc without metal catalyst and graphite additive. The sharp spectral peaks from all Raman active phonon modes have been distinctly observed. However, no pronounced quantum confinement effect has been observed for the tetrapod-like nanostructure with diameter of 50 nm. In addition, larger red shifts of longitudinal-optical phonon scattering peaks, compared with bulk ZnO, were observed in the single tetrapod-like nanostructure, which were primarily attributed to laser-induced heating or/and the phonon localization effects.