DARPA funded research creates semiconductors without silicon

In a major breakthrough that could change the very face of modern electronics, a team of scientists from UC San Diego, have created a path-breaking discovery: vacuum tubes can lead to faster chips which can retain more power. This will have wide-ranging application.

A quarter of a century back at the time when computing was in the age of dinosaurs, vacuum tube powered transistors ruled the tech world. Thanks to researchers from UC San Diego, these giants are set to make a comeback.

Yes you read that right. The scientists have created the world’s first semiconductor-free, laser-controlled microelectronics device that works on free electrons, just like vacuum tubes do. The impact of their findings could significantly improve the way solar panels work and create much faster microelectronic devices, which can retain more power.

While silicon based semiconductors and other materials that are currently in vogue today are great since they have helped us squeeze billions of transistors into just a few square inches, the issue with them is that their electron velocity is limited by the resistance of their material. So as to get them flowing, a little shove in the form of an energy boost is required so that they can fill the “band gap” caused by the insulating properties of semiconductors such as silicon.

As you may have guessed, vacuum tubes don’t face this issue. They can dislodge free electrons to carry (or not to carry) a current through space. Problem is, getting free electrons at nanoscale is a problem. This is where a powerful laser or high voltages come handy. A little shock with these can knock them loose and get them flowing.

The approach the UC San Diego scientists took was to build gold “mushroom” nanostructures which have adjacent parallel gold strips. By combining just 10V with a low-powered laser, they managed to dislodge electrons from the gold strips.

As a result, the conductivity increased by nearly a factor of 10, i.e – 1,000%. As per their research report, published in Nature, this significant change got them to realise that “the structure performs as an optical switch”.

This tiny device, can now act as a power amplifier or a photodetector, just like semiconductors but with the added theoretically benefit of having less resistance and being able to handle higher amounts of power.

Although, this research is a proof-of-concept, it is extremely promising.

“Next, we need to understand how far these devices can be scaled and the limits of their performance,” says Dan Sievenpiper, who authored the report.

The researchers now aim to explore applications environmental applications, photovoltaics and the military, since after all the research was funded by DARPA.


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