Alan Doolittle, a professor of computer engineering at Georgia Tech, and his team discovered a way to use aluminium nitride (AlN) to create an ultrawide bandgap (UWBG) semiconductor that can be used at significantly higher power and temperature levels than previously possible — and at more than five times the voltage of current wide bandgap semiconductors. Because UWBG semiconductors are more durable, high-voltage circuits may function more effectively and efficiently with fewer semiconductor components.
Aluminium nitride (AlN), a material that has long been utilised as an electrical insulator, may hold the key to revealing the new potential for LEDs, high-power electronics, and optoelectronics. Engineered ceramic is used in electronic devices for heat dissipation because of its excellent thermal conductivity and electrical insulating properties.
"It's rare to see such encouraging early results," said Alan Doolittle. "To put things into perspective, AlN can handle over five times the voltage of other existing wide bandgap semiconductors. It really is the birth of a new semiconductor field."
Electronic devices, the most basic of which is a diode, require two kinds of semiconducting materials to function: one that carries positive, or p-type, charges and the other that carries negative, or n-type, charges. The Georgia Tech research team altered p-type and n-type aluminium nitride (AlN) to perform 30 million times better than their current conduction.
According to a Georgia Tech article, a bandgap is the minimum energy needed to excite an electron into a conduction state, allowing electricity to flow through a material. The bandgap also affects the breakdown voltage at which a device fails and is related to the wavelength of light produced by the material.
The scientists grew the AlN crystals at temperatures far lower than those typically used to make semiconductor materials. The low-heat method may be a game-changing breakthrough in and of itself since it permits more precise control of the material's surface chemistry during the manufacturing process.
AlN has a promising future as a semiconductor material, although research is still in its infancy. Finding a suitable interface for the UWBG semiconductor that can transfer current to electrical devices is one of the numerous issues Doolittle and his team are solving as they move into the prototype and optimisation phases.
"In general, semiconductors with larger bandgaps can handle more power than those with lower bandgaps, and this is true for AlN as well. At 6.1 eV, AlN … should be able to handle the most power of any semiconductor material. In combination with some other properties of AlN, this means that semiconducting AlN could be used to enable smaller, higher-power transistors that are more efficient with reductions in both thermal and electrical losses," said Chris Matthews, research co-author and doctorate candidate at Georgia Tech.
The use of gallium nitride (GaN), a semiconductor material with a broad bandgap of 3.4 eV, to produce high-energy blue LED light was the subject of a Nobel Prize-winning discovery. Due to its greater bandgap, AlN emits deep ultraviolet (UV-C) light with a 203-nm wavelength that is approximately twice as energetic as GaN's UV light with a 365-nm wavelength.
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According to Chris Matthews, research co-author and doctorate candidate at Georgia Tech, other potential optical uses for AlN LEDs and lasers include communications, lithography, and laser cutting. Utility grids can manage the amount and destination of transmitted power thanks to the AlN semiconductor material's capacity to withstand high voltages, particularly when existing systems combine with microgrid and renewable energy technologies.
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