Synthesis of large-scale periodic ZnO nanorod arrays and its blue-shift of UV luminescence

We demonstrate a promising route to fabricate large scale hexagonally patterned, vertically aligned ZnO nanorod arrays with small diameter. By adding 3-mercaptopropyltriethoxysilane (MPTES) molecules as a connection between catalyst and substrate the large size dispersion resulting from the removal of catalyst pattern is avoided, thus the catalyst particle pattern with tiny size dispersion and regular shape is obtained; the size can be tuned in a large range from 50 nm to 300 nm. Using this technique, ZnO nanorod arrays with tunable spacings and diameters are achieved, which also have uniform shape and length, good crystal quality, and vertical alignment on the substrate. Moreover, a pronounced blue-shift of ultraviolet (UV) luminescence spectra of ZnO nanorods with their diameters decreasing is observed. Combining the temperature-dependent photoluminescence (PL), we suggest that a materially decreased exciton-phonon interaction with the reduced diameter of ZnO nanorods is the main reason for the blue-shift of UV luminescence.