The solution for next-generation nanowires comes out of thin air

Researchers at RMIT University have come up with a new type of transistor, the building block of all electronics. Instead of sending electrical currents through the silicon, these transistors send electrons through narrow air gaps, where they can travel unhindered, as in space.

The device unveiled in the journal Nano Letters (Materials Science) eliminates the use of any semiconductor, making it faster and less subject to heat.

Dr. Shruti Nirantar, lead author and PhD candidate of RMIT's Functional Materials and Microsystems Research Group, said this promising proof-of-concept design for nanoscreens, a combination of metal and void space, could revolutionize electronics.

"Every computer and every phone has millions or even billions of silicon electronic transistors, but this technology reaches its physical limits where silicon atoms hinder the flow of current, limiting speed and generating heat," he said. Nirantar.

"Our air channel transistor technology circulates the current in the air, so there is no collision to slow it down or resistance in the material to produce heat."

Moore's law

The power of computer chips – or the number of transistors pressed onto a silicon chip – has risen predictably for decades, doubling every two years or so. But this rate of progress, known as Moore's Law, has slowed in recent years, as engineers struggle to reduce the size of transistor components, which are already smaller than the tiniest viruses.

According to Nirantar, their research is a promising avenue for nanoelectronics in response to the limitations of silicon-based electronics.

"This technology simply takes a different path from the miniaturization of a transistor to enforce Moore's law for many more decades," said Shruti.

A new way forward

Sharath Sriram, head of the research team, said the design corrects a major flaw of traditional solid-channel transistors – they are filled with atoms – which means the electrons that cross them collide, slow down and waste energy in the form of heat.

"Imagine walking in a busy street trying to get from point A to point B. The crowd slows your progress and drains your energy," Sriram said.

"On the other hand, traveling in a vacuum is like an empty highway where you can drive faster with greater energy efficiency."

But if this concept is obvious, the vacuum packaging solutions around the transistors to make them faster would also make them much larger, so they are not viable.

"We approach this by creating a gap at the nanoscale between two metallic points. The gap is only a few tens of nanometers, 50,000 times smaller than the width of a human hair, but it's enough to fool the electrons into believing that they travel in a vacuum and recreate a virtual outer space for electrons in the nanometer gap, "he said.

The device at the nanoscale is designed to be compatible with the manufacturing and development processes of modern industry. It also has applications in space – both as radiation-resistant electronics and for using electron emission for the control and positioning of "nano-satellites".

"It's a step towards exciting technology that aims to create something out of nothing to dramatically increase the speed of electronics and keep pace with rapid technological progress," Sriram said.

This work was undertaken at RMIT's Micro Nano Advanced Research Center and supported by the Victorian Node at the Australian National Manufacturing Center.

Story: Michael Quin