Last week, Anker debuted a tiny new power brick, crediting its small size with the component it uses instead of silicon: gallium nitride (GaN). It’s the latest example of the growing popularity of this transparent, glass-like material that could one day unseat silicon and cut energy use worldwide.
For decades now, silicon has been the backbone of the technology industry, but we are “reaching a theoretical limit on how much it can be improved,” says Danqing Wang, a doctoral candidate at Harvard University who conducts GaN research. All materials have a “band gap,” which is related to how well they can conduct electricity. GaN has a wider band gap than silicon, which means it can sustain higher voltages than silicon can survive, and the current can run through the device more quickly, says Martin Kuball, a physicist at the University of Bristol who leads a project on GaN in power electronics.
As a result, GaN electronics are far more efficient than their silicon counterparts, and they lose less energy. “You can make things very small, or you can pack more GaN in the same area,” says Wang. “The performance is better.” And when you lose less energy, not only can you make charging devices smaller, but you can also use less power in the first place. According to Kuball, replacing all current electronics with GaN could potentially cut power use by 10 or 25 percent.
Plus, because GaN can survive at higher temperatures than silicon, using it can influence design in more complicated environments. Right now, the electronics in a car are mounted far away from the engine to keep them from getting too hot, says Kuball. GaN erases this constraint and could open up new possibilities that change how cars are designed in the future.
The material has long been dominant in another area: lasers and photonics. GaN is one of the few materials to give off blue light; it’s used in Blu-rays to make disc-reading possible. It’s also frequently used in LEDs. Wang’s team is making tiny GaN lasers the size of a micron — which is 1/100th the size of a human hair and too small to see with the naked eye — that can be used in microscopes to make research more precise.
Photonics aside, why haven’t we replaced silicon with GaN yet? “Silicon is very mature,” says Kuball. “People are used to it and have been doing this for a long time, and obviously what you find when you introduce a new type of material or electronic is that you need to keep testing it for reliability.” GaN isn’t a perfect material either, adds Wang, because some methods of growing it can cause defects that make it less effective.
But we’re used to silicon. It’s cheap, and all the manufacturing techniques are already set up for it. GaN is still a little more expensive. “It takes some effort to switch to gallium nitride,” says Wang, though she points out that some people are looking at ways to grow gallium nitride crystals on top of silicon in the hopes of taking advantage of the existing manufacturing platforms.
Large semiconductor manufacturers like Texas Instruments and Nexperia do have GaN research programs, according to Kuball, and there’s no shortage of startups working on the technology. Still, we have yet to see the true impact of GaN in the power electronics field. “These little adapters are a nice toy, but where GaN will really matter is in converters for electric cars and photovoltaics,” Kuball adds. In the meantime, “it’s a cool little thing to have something smaller.”
Anker was not available for comment as of press time.