Beryllium-doped gallium nitride for next-gen power electronics

Aalto University physicists have discovered a microscopic mechanism that will allow gallium nitride semiconductors to be used in electronic devices that distribute large amounts of electric power. Their secret? Doping gallium nitride with beryllium atoms.

Gallium nitride is a compound widely used in semiconductors in consumer electronics from LED lights to game consoles. However, to be useful in devices that need to process considerably more energy than your everyday home entertainment system, gallium nitride needs to be manipulated on the atomic level.

“There is growing demand for semiconducting gallium nitride in the power electronics industry,” said Aalto’s Professor Filip Tuomisto. “To make electronic devices that can process the amounts of power required in, say, electric cars, we need structures based on large-area, semi-insulating semiconductors with properties that allow minimising power loss and can dissipate heat efficiently.”

Experiments with beryllium doping were conducted in the late 1990s in the hope that beryllium would prove more efficient as a doping agent than the prevailing magnesium used in LED lights. The work proved unsuccessful, however, and research on beryllium was largely discarded.

Now, working with scientists in Texas and Warsaw, the Aalto researchers have now managed to show — thanks to advances in computer modelling and experimental techniques — that beryllium can actually perform useful functions in gallium nitride. Their research shows that depending on whether the material is heated or cooled, beryllium atoms will switch positions, changing their nature of either donating or accepting electrons.

“Our results provide valuable knowledge for experimental scientists about the fundamentals of how beryllium changes its behaviour during the manufacturing process,” said Professor Tuomisto. “During it — while being subjected to high temperatures — the doped compound functions very differently than the end result.”

If the beryllium-doped gallium nitride structures and their electronic properties can be fully controlled, the researchers believe power electronics could move to a whole new realm of energy efficiency.

“The magnitude of the change in energy efficiency could be as similar as when we moved to LED lights from traditional incandescent light bulbs,” said Professor Tuomisto. “It could be possible to cut down the global power consumption by up to 10% by cutting the energy losses in power distribution systems.”

The study has been published in the journal Physical Review Letters.