Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 44: Nanostructures at surfaces: Dots, particles, clusters, arrays III
O 44.5: Talk
Wednesday, March 16, 2011, 12:15–12:30, WIL C107
Electrochemical formation of Self-Organized Superlattice Nanotube Arrays - Embedding Heterojunctions into Nanotubes Walls — •Wei Wei1, Himendra Jha1, Guang Yang2, Erdmann Spiecker2, and Patrik Schmuki1 — 1Department of Materials Science WW-4 ( LKO), University of Erlangen-Nuremberg, Erlangen, Germany — 2Center for Nanoanalysis and Electron Microscopy, University of Erlangen-Nuremberg, Erlangen, Germany
In recent years, a simple and convenient approach to form ordered transition metal oxide nanotubes arrays, i.e. self-organized electrochemical growth method, has attracted wide interests.In present work, we demonstrate how this simple anodization technique can be used to produce highly defined superlattice oxide nanotube arrays on metallic substrates. Under optimized growth conditions, a self-organization process occurs that yields 3D ordered nanotube arrays with regular nm-spaced modulations in the tube wall composition.An example will be shown where we prepared TiO2/Ta2O5 confined heterojunction nanotubes arrays, each of which contains approx. 100 periods of modulated pairs. The electronic properties in the tube wall alternate with a sub-20nm precision, which yields a significant phonon confinement effect. These structures are also expected to drastically enhance efficiencies in charge transfer devices. The process, however, is versatile (transferrable to a broad range of metal oxide junctions), allows tuning of the tube and superlattice geometry, neither requires UHV conditions, nor expensive equipment, and due to its parallel processing nature, it can easily be scaled up.