Feb 19, 2013
AAO nanochannels reshaped into vertical fan-out platform
Researchers from National Cheng Kung University, Academia Sinica and National Taiwan University have developed a two-step anodization technique, which changes the shape of anodic aluminum oxide (AAO) nanochannels and bends the tiny tunnels into a vertical fan-out structure. The nanoarchitecture is useful for bridging nanostructures of different scales – for example, in electronic devices.
In the process, the Taiwan-based team first patterns a custom-designed triangular "cell" with three nanoholes on an aluminum sheet surface by focused-ion-beam lithography. The nanoholes can be made to grow into straight nanochannels by applying a suitable voltage in the first step of the anodization process.
Next, the group uses a doubled voltage to induce lateral repulsion between growth fronts originating in the same cell. As a result, the fronts “fan out”. The fan-out evolution continues until the growth fronts originating in all of the cells evolve into a close-packed two-dimensional hexagonal lattice.
This novel platform facilitates the probing and handling of many signals from different areas on a non-planar sample’s surface. The design element could help to improve detection and manipulation at the nanoscale level.
Additional information can be found in the journal Nanotechnology.
About the author
Dr Chih-Yi Liu is an assistant research fellow in the Department of Photonics and Advanced Optoelectronic Technology Center at National Cheng Kung University, Taiwan. His research interests include fabricating porous templates, such as anodic alumina films, for the growth of various nanocomposites. Applications include optical and plasmonic sensing.