Thanks to a group over at the Rensselaer Polytechnic Institute, hybrid carbon-metal nanostructures might any day be making a honeymoon journey into an implantable medgadget:
The new structures, which are described in a recent issue of Applied Physics Letters, could help overcome some of the key hurdles to using carbon nanotubes in computer chips, displays, sensors, and many other electronic devices.
The impressive conductivity of carbon nanotubes makes them promising materials for a wide variety of electronic applications, but techniques to attach individual nanotubes to metal contacts have proven challenging. The new approach allows the precise attachment of carbon nanotubes to individual metal pins, offering a practical solution to the problem of using carbon nanotubes as interconnects and devices in computer chips.
“This technique allows us to bridge different pieces of the nanoelectronics puzzle, taking us a step closer to the realization of nanotube-based electronics,” said Fung Suong Ou, the paper’s corresponding author and a graduate student in materials science and electrical engineering at Rensselaer.
As chip designers seek to continually increase computing power, they are looking to shrink the dimensions of chip components to the nanometer scale, or about 1-100 billionths of a meter. Carbon nanotubes and nanowires that became available in the 1990s are promising candidates to act as connections at this scale, according to Ou, because they both possess interesting properties.
For example, carbon nanotubes display amazing mechanical strength, and they are excellent conductors of electricity, with the capacity to produce interconnects that are many times faster than current interconnects based on copper. Gold nanowires also have very interesting optical and electrical properties, and they are compatible with biological applications, Ou said.
“In order to take full advantage of these materials, we demonstrate the idea of combining them to make the next generation of hybrid nanomaterials,” he said. “This approach is a good method to marry the strengths of the two materials.”
The metal nanowires in this technique are made using an alumina template that can be designed to have pore sizes in the nanometer range. Copper or gold wires are deposited inside the pores, and then the entire assembly is placed in a furnace, where a carbon-rich compound is present. When the furnace is heated to high temperatures, the carbon atoms arrange themselves along the channel wall of the template and the carbon nanotubes grow directly on top of the copper wires.