| AVS 54th International Symposium | |
| Thin Film | Wednesday Sessions |
| Session TF-WeA |
| Session: | Oblique Angle Deposition |
| Presenter: | Y.P. He, University of Georgia |
| Authors: | Y.P. He, University of Georgia Y.P. Zhao, University of Georgia |
| Correspondent: | Click to Email |
One-dimensional (1D) heterogeneous nanostructures are important building blocks for nanodevice applications. Four basic methods have been employed thus far to fabricate heterogeneous 1D nanostructures: nanolithography, direct chemical reaction, template-directed electroplating, and vapor-based methods. A practical nanofabrication technique to produce heterogeneous nanostructures with arbitrary materials must meet the following criteria: (1) The ability to fabricate heterogeneous nanostructures with arbitrarily selected materials; (2) The ability to control the dimensions and uniformity of the heterogeneous nanostructures; (3) The ability to control the alignment of the heterogeneous nanostructures; (4) The ability to control the interfacial properties of the heterogeneous nanostructures. Here, we demonstrate a simple but versatile method to fabricate three-dimensional heterogeneous nanorod structures by multilayer dynamic shadowing growth (DSG). DSG is based on geometric shadowing effect and substrate rotation in a physical vapor deposition system. By programming the azimuthal rotation of the substrate, aligned nanorod arrays with different shapes can be fabricated. By changing the source materials during the deposition, we demonstrate that complicated heterostructured nanorod arrays, such as Si/Ni multilayer nanosprings,1 can be easily produced, and they exhibit particular magnetic anisotropic behavior. We also use the DSG technique to design catalytic nanomotors2 with different geometries that are capable of performing different and desired motions in a fuel solution. Using the shadowing effect, a thin catalyst layer can be coated asymmetrically on the side of a nanorod backbone. Catalytic nanomotors such as rotary Si/Pt nanorods, rotary L-shaped Si/Pt and Si/Ag nanorods, and rolling Si/Ag nanosprings, have been fabricated, and their autonomous motions have been demonstrated in a diluted H2O2 solution. We observed that the catalytic decomposition of H2O2 on the surface of catalyst generated a propelling force to push the nanorod from the catalyst side with an estimated driving force on the order of 10-13 - 10-14 N. This fabrication method reveals an optimistic step toward designing integrated nanomachines.
1 Y.-P. He, J.-X. Fu, Y. Zhang, Y.-P. Zhao, L.-J. Zhang, A.-L. Xia, and J.-W. Cai, Multilayered Si/Ni Nanosprings and Their Magnetic Properties, small 2007, 3(1), 153-160.
2 Y.-P. He, J.-S. Wu, and Y.-P Zhao, Designing Catalytic Nanomotors by Dynamic Shadowing Growth, Nano Lett. 2007, 7(5), 1369-1375.