Nanotechnology
The researchers hope that this achievement may lead to the development of extremely strong, lightweight materials and ultra-dense nano-memory arrays for extremely powerful computers, ultra-low-loss power transmission lines, and nano-biosensors for use in health care applications. A nanotube is commonly made from carbon and consists of a graphite sheet seamlessly wrapped into a cylinder only a few nanometres wide.
The research leader, Peter Burke, assistant professor of electrical engineering and computer science, dds: "Significantly, we have found that our nanotubes have electrical properties superior to copper. This clearly shows for the first time that long nanotubes have outstanding electrical properties, just like short ones."
The team, which includes graduate students Shengdong Li, Christopher Rutherglen and Zhen Yu, grew the carbon nanotubes using a simple procedure.
A natural gas reacts chemically with tiny iron nanoparticles inside a small furnace. By placing a small amount of gold under the iron, Burke's group found that ultra-long nanotubes grow, whereas without the gold, only short tubes result.
Because nanotubes are so small, it is difficult to connect regular wires to them. An added advantage of using gold in the growth process is that that the nanotubes come out already attached to gold wires. Further, the team was able to accurately determine how the electrical resistance of a nanotube depends on its length. The relationship between resistance and physical size (length) is a key property of any new material. Burke's finding indicates that the electrical conductivity is greater than that of copper wires of the same size, a world record for any nano-material of this length.
The US Army Research Office, the US Office of Naval Research, the US Defense Advanced Research Projects Agency (DARPA) and the US National Science Foundation (NSF) provided funding for the research. NanoDynamics has signed a joint venture agreement with a New Zealand-based technology company, Nano Cluster Devices (NCD).
NanoDynamics will be working to commercialise NCD's technology process for self-assembly of nanowires in production of semiconductors and electronic components. Under the agreement, NanoDynamics will be responsible for sales and application development, as the company targets semiconductor companies, consumer applications, aerospace, biotech and industrial manufacturers. NCD will be responsible for the further advancement of the technology platform.
NCD, in conjunction with the University of Canterbury (New Zealand), has developed a process to make electrically conducting nanowires through the deposition of atomic clusters onto lithographically prepared templates. The NCD technology produces small, well-controlled linear structures with different functionalities on a range of substrates.
The key feature of NCD's technology is that it is essentially a self-assembly process - avoiding the slow manipulation of nano-sized building blocks, which is often unavoidable in many other nanotechnologies. The nanowires produced are smaller in size, and more economical to apply due to their controlled placement and use of existing semiconductor processes. The companies hope to use the methodology across a wide range of applications including hydrogen and other chemical sensors for power distribution and other industries, magnetic read heads for computer hard drives, and discrete transistors and interconnects for various semiconductor and electronic devices.
Keith Blakely, CEO of NanoDynamics, comments: "As part of our corporate strategy, NanoDynamics is building an intellectual property portfolio able to provide significant product and technology value to a wide range of customers and partners."
