Chemical Engineers' Process Grows Crops Of Nanowires

The ultrasmall structures, which are one-thousandth the size of a human hair, are expected to lead to improved design of advanced military and space gear and clothing, fuel cells, sensors and solar devices. They could also be used to fight bioterrorism more effectively.

The growing technique is novel because it uses pools or thin films of low-melting metals such as gallium to create the nanowires and uses gas-phase chemistry to control their size. Previously, scientists have assumed gold or iron clusters are needed to make a pattern for one-dimensional growth of materials.

The process also allows the scientists to grow nanowires in bulk quantities.

The research team grows crops of nanowires by spreading a thin film of molten gallium on a solid surface and exposing it to a gas in an excited state. By controlling the chemistry in a reactor, the group can form multiple nuclei that grow into multiple wires.

The process has worked using silicon, carbon, gallium oxide and gallium nitride nanowires.

Chemical engineer Mahendra Sunkara will give a presentation on the process in November at annual meetings of the Materials Research Society and the American Institute of Chemical Engineers.