Process orders nanowire arrays

Harvard University researchers have found a way to neatly layer and pattern rows of nanowires.

The method is a step toward using the microscopic wires to build electronics components from the ground up rather than the usual top-down approach of photolithography, which uses light and chemicals to etch components into chips made from semiconductors like silicon.

The researchers used nanowires that were 45 and 90 nanometers in diameter. A nanometer is the span of 10 hydrogen atoms. The arrays could be used to form devices like nanoscale light-emitting diodes and densely-packed computer chips.

The researchers used a previously reported technique to align a layer of nanowires in solution, and formed structures of parallel or crossed nanowires by transferring each layer to a surface, or substrate. They then used photolithography methods to further pattern the nanowire structures into arrays of nanowire field-effect transistors.

The method allows for control of the orientation and spacing of the nanowires, and the orientation, size and spacing of the arrays that form each layer of the structure. This makes it possible to construct practical electronic devices from nanoscale components like nanowires.

The researchers are working on making more complicated arrays, and ways to interconnect the wires.

Some applications, like nanosensor arrays and large-scale electronic devices, could be practical within two years, according to the researchers. The work appeared in the September 10, 2003 issue of Nano Letters.