Pittsburgh (PA) – In the future, very small devices will require very small amounts of electricity. Yet, how can future nanoscopic circuits at such levels be created? Scientists have found at least one answer: Carbon-60 nanowires.
Researchers at the University of Pittsburgh have discovered an assembly technique which provides a way to construct one-dimensional nanowires. With no height or width outside of the fullerene (soccer ball-like) molecular size, and of only sub-micon length, these wire products could form the building blocks of extremely tiny man-made machines in the future, those on the order of 1000s of atoms or molecules in total size.
Additional research, carried out by Dr. Hrvoje Petek and his team, has indicated that other non-fullerene organic structures can also be created using the same assembly technique. However, inorganic structures cannot be created because it’s one of the properties of carbon-chain molecules which allow this assembly technique to work. Inorganic materials like silicon are naturally disposed to forming three-dimensional structures, making them difficult if not impossible to create in an assembly method such as this.
The process literally begins at the atomic level. Copper-110 atoms form a flat crystaline plane (like a sheet of paper). From there, Oxygen-Copper-Oxygen (CuO2) molecules are chemically deposited on top of the plane (like rows of corn), but with a full copper-atom left exposed between the oxygen rows which is not molecularly bonded to the Cu02 rows. This creates a type of trough, which serves basically as a mold for their construction. From there, the Carbon-60 fullerene molecules are introduced and a self-assembly process begins. The molecular chains of varying lengths are created naturally within the molds.
Experimentation has determined the amount of heat required for the annealing process to produce the highest yield and longest usable chains. The end result? While the mold itself is less than 2 nm wide, nearly perfectly aligned single-molecule wires in excess of 100 nm have been created.
The molecules are spaced approximately 0.76 nm apart. This makes their arrangement very close to the ideal of 0.73 nm. In the future, it will be possible to remove these tiny structures from the copper mold. Once extracted, they could then serve as foundational “raw materials” which might be resized and moved into position for whatever practical use is required.
These nanowires then form Carbon-60 structures which exhibit a most desirable property. When conducting electricity at these nano-scale levels there is only a minimal loss due to their one-dimensional nature. Electrons cannot be scattered in the other two dimensions and are forced down the one-dimensional path. This could make them ideally suited for micro-leads in future ultra-tiny MEMS (micro-electro-mechanical systems) which could operate in the picoamp range with possibly only 100s to 1000s of atoms comprising the entire structure. Their natural molecular chain-like structures forms the requisite wire shape. Their natural property of electrical conveyance makes them ideally suited for small electrical loads.
Similar nanowires constructed from other organic molecules in the future could also form the most basic of insulating, structural and conductive components and circuits. Altogether, nanostructures built like these may well enable the micro-machine devices of tomorrow to be practically built. This research could make those future devices not only more controllable and programmable, but also built using components which are relatively easy to construct, test and deploy.
Dr. Petek told us “I believe organic molecules can have a broad variety of properties or functions that are not available in silicon. These could be used in applications that we cannot extrapolate from the present silicon technology.”