DNA-based fabrication of density-controlled vertically aligned ZnO nanorod arrays and their SERS applications

We described a novel seeded synthesis of vertically aligned ZnO nanorod arrays on a DNA network surface. Zinc ions were first adsorbed onto the DNA network and then heated to yield layers of ZnO seeds. The DNA network plays an important role not only as a substrate for the adsorbing of zinc ions, but also as a fine template for density controllable synthesis of high-quality ZnO seeds. The density of ZnO seeds was controlled by the adsorption times of zinc ions. The final density of ZnO nanorods was determined mainly by that of ZnO seeds. The ZnO nanorod arrays were used as templates for making silver-coated ZnO nanocomposites, which were applied as substrates in surface-enhanced Raman scattering (SERS) measurements. Two typical probe molecules, R6G and 4-ATP were used to test the SERS activity of the ZnO/Ag composites and the results indicated good Raman activity on the substrate.