Vapour-phase growth, purification and large-area deposition of ZnO tetrapod nanostructures

Large-yield zinc oxide (ZnO) nanosized tetrapods have been obtained by a standard vapour-phase growth technique to which a few modifications have been added, such as the separation of the Zn source evaporation region from the Zn oxidation region inside the reactor setup. This modification allows to keep the growth conditions constant and continuous for a long time, thus favouring the obtainment of large amounts of ZnO tetrapod nanostructures. As some contaminations usually occur due to metallic Zn particles and/or different ZnO nanostructures, including not completely reacted ZnO1-x solid phases, they can be removed by a three-step "purification" procedure as described in the article. Further to that, a deposition method from suitable liquid suspensions is also reported, which allows to produce homogeneous distributions of ZnO tetrapods on large substrate areas. The proposed procedures are expected to be particularly appropriate for a large production of samples for device use.