Fabrication And Replication Of Heteromorphic Structured Template Based On Anodic Aluminum Oxide

With the development of nanotechnology, the growing demand for functional nanoscaledevices has led to great progress in accurate controlling of nano-structure. The complexnano-structure templates combined with replication technique have obvious advantage infabrication of nanoscale devices. Among the templates, anodic aluminum oxide (AAO) havemany advantages such as high degree of order, tunable pore size and space, controllablemembrane thickness and have atrracted attention from scientists. Various kinds of AAO withheteromorphic structure can be obtained by different preparation conditions, and thereplication of heteromorphic AAO would be an extremely valuable method to prepare nanoarrays.In present thesis, porous AAO structure with branched channels is fabricated by gradualreduced voltage following with sine increased voltage and the function of step down voltageis peformed after analysing the voltage-current density curve and morphology of AAO.Channels of porous branched AAO can be interconnected with appropriate chemical etchingand the appropriate etching time is determined by analysing the microstructure. Usingmulticycle step down function of anodic oxidation combined with appropriate chemicaletching, porous branched interconnected layer-by-layer AAO template are obtained. Based onthe present template, porous carbon materials are negative replicated. The carbon materialshave following characteristics: periodic interconnected layer-by-layer structure, high degreeof graphization, coexistence of macropore and micropore and excellent electrochemicalenergy storage characteristics.In present thesis, ordered AAO templates with large pores are also fabricated by highvoltage anodic oxidation. The characteristics of reflecting grating is confirmed for aluminumsheet after removing the oxide membrane by the reflecting spectrum and the morphology ofthe aluminum sheet is also observed. The obvious diffraction peak of aluminum sheet showsits high degree of order. The pore space of400nm is observed from SEM results inaccoradance with the calculated value from reflective spectrum and it means that spectrummeasurement could replace SEM for non-destructive characterization of sample to a certaindegree. Combing repeated anodization with pore widening treatment, ordered cone-shapedAAO templates with large pores have also been fabricated and the morphology shows theregular hexagonal array and bowl-shaped round holes. Cone shape can be directly observedfrom cross-section morphology and the ratio of length to diameter increases with prolongingsecond-step anodization time. Based on the cone shape template, nanomaterials with unique morphology are successfully fabricated using electroless plating and electroforming.