News in Science

Nanowires to rev up computers of tomorrow

Nanowire chips Computer circuits of the future could be built in three dimensions and operate using light rather than electricity, say Australian researchers.

A team of nanotechnologists at the Australian National University (ANU) in Canberra have successfully produced laser light using wires just a few billionths of a metre in diameter.

This advance is a key step toward constructing computer chips for the future, they say.

Building computer circuits using light could bring a host of advantages, says Dhruv Saxena, a PhD student, who was the lead author on the study, published in the journal Nature Photonics today.

"Light transmits faster than electrons, so we can have faster computers, smaller chips that are more energy efficient," he says.

"If we use nanowires and light we can think of three-dimensional circuits with light interconnecting and passing information between layers and have much more compact, faster processors."

The tiny lasers could potentially also be used for ultrasensitive optical sensors and for near-field optical microscopy, the researchers say.

Growing nanowires

The major advance achieved by the ANU researchers is finding a way to grow tiny wires made of a compound called gallium arsenide that can function at room temperature.

The researchers achieved this by depositing tiny gold particles onto a surface and heating it to 750°C in the presence of gasses containing gallium and arsenic.

Under these conditions, the gallium and arsenic react to form solid crystal "wires" that can direct light, explains Dr Sudha Mokkapati, a co-author on the paper.

"The gallium arsenide has a very high refractive index compared to air so it guides light through it, and the ends of the nanowires act as mirrors," she says.

Saxena says building computer chips from these wires would still require years of development, but showing that the nanowires can operate at room temperature is an important development.

"There are a lot of steps down the track, but groups have been trying to do this for 10 years."