Research:
Nanostructures for novel devices

Nanostructures for energy devices

In collaboration with Prof. Sang Bok Lee's group, we are exploring how self-assembly phenomena combined with self-aligned processes can serve as the basis for developing novel nanostructures as devices for energy capture and storage. The focus is on anodic aluminum oxide (AAO) nanostructures with atomic layer deposition (ALD) and electrochemical deposition (ECD) to form the devices, where AAO formation provides self-assembled nanopores of well-defined dimensions and alignment, while ALD enables unprecedented capability to deposit self-aligned layers into the ultrahigh aspect ratio nanopores. These process combinations offer potentially very high active volumes and surfaces for energy devices.

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Characterization of multilayer structures in nanopores

We have developed methods for nanocharacterization of multilayer ALD/ECD layers formed within AAO nanopores. Nanotubes and nanowires formed in AAO nanopores are readily released through wet etching of the AAO template, so that the nanostructures can be measured in detail by high resolution TEM. We have also developed image processing algorithms which determine the profile of the structures along the axis of the original nanopore, and we are working to achieve compositional and chemical bonding information from analytical TEM. These methods serve two goals: (1) determining ALD profiles in difficult geometries, comparing them to ALD conformality models, and understanding process mechanisms; and (2) evaluating ALD/ECD films and profiles in the context of metrics needed for energy devices made from arrays of nanopore-based structures..

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AAO-ALD nanodevices and energy systems

We are also exploring how arrays of individual nanopore-based structures can be aggregated and configured to achieve useful energy devices and systems. This requires optimization of array size and defect density as well as process integration strategies for array fabrication. In addition to expected structures built in vertical AAO nanopores, we have conceived lateral nanopore device arrangements (patents in process) which appear particularly promising in terms of both fabrication and integration into systems.

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