Copper Nanowires Tuned Using Ion Track Templates and Electrochemical Deposition
The hallmark of materials science is the ability to tailor the structure of a given material to provide a desired response. Nanomaterials with controlled structural properties are interesting for fundamental research, thanks to their unique structural and physical properties compared with their bulk counterparts, and also offer fascinating prospects for future technological applications.
A variety of strategies have been developed to fabricate metallic nanowires, but controlling structural characteristics remains a challenge. Now, researchers from China and Pakistan investigating the properties of Cu nanowires have shown that crystallinities and crystallographic orientations can be controlled using electrochemical deposition in combination with ion tracks.
The team, which includes scientists from the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS) and PINSTECH, Pakistan, first use accelerators (HIRFL at IMP, UNILAC at GSI) to produce polymer templates. Then Cu wires are formed by electrochemically depositing material inside the templates nanopores.
Functional fabrication
The study reveals that low voltage and high temperature are favorable growth conditions for single crystalline wires, whereas, high voltage and low temperature are beneficial to the growth of polycrystalline wires. In polycrystalline wires, the anti-Hall-Petch effect is evident as predicted by theory. In addition, wires with preferred crystallographic orientations along [111], [100], or [110] directions can be modulated by changing the deposition conditions.
These findings imply that the techniques of electrochemical deposition in combination with ion-track membranes may provide a high degree of flexibility to grow metal nanowires with arbitrary structures and, as a result, offer a way to control the material s functional performance.
A method for other materials
Although further studies are still needed involving different materials and sizes, these findings represent a step forward in understanding how to control the structural properties of metal nanowires. This challenge has captured the attention of a large part of the scientific community for the last two decades.
Due to similar growth mechanisms, the group's results may help in the structural tuning of other materials such as gold, silver, platinum, palladium, nickel, cobalt, bismuth, antimony, lead, tin, zinc, and so on.
The researchers presented their work in the journal Nanotechnology.
About the author
Researchers from the Materials Science Department II at IMP, CAS, have worked on nanomaterials since the beginning of this century. A variety of materials, including Au, Cu, Ag, CdS, Pd, Pt, and polypyrrole have been successfully synthesized within ion-track templates and their physical properties such as optical, magnetic, mechanical, and electrical properties have been investigated. In addition, the group has investigated the irradiation effects of solid materials under normal and extreme conditions, single event effects of semiconductor devices, and the preparation and application of nuclear track membranes. Prof. Dr Jie Liu is head of the Materials Science Department II at IMP. Dr Jinglai Duan received his MS and PhD degrees under the supervision of Prof. Liu in 2005 and 2008, respectively. He is now an assistant professor based at IMP. His research interests include the preparation and characterization of metal nanowires. Dr Huijun Yao is also an assistant professor at IMP and is currently a visiting scholar of the J lich Research Center, Germany. His research interest is GMR effects of nanowires. Dr Dan Mo is an assistant professor at IMP and is currently working on nanowires and ion-track membranes. Dr Khan Maaz is a research fellow at PINSTECH, Pakistan. He was a visiting scholar at IMP in 2008. Assoc. Prof. Youmei Sun's research interests include irradiation effects on polymer films and preparation of photonic crystals using swift heavy ions. Prof. Mingdong Hou was the former head of the department of Application I at IMP. His research interests include irradiation effects on amorphous metal alloys and single event effects in large scale integrated circuits. (Nanotechweb.org)
