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Phoenix666 [soylentnews.org] writes:

Ideally, the electronic components that route electricity [ieee.org] throughpower supplies, inverters, and electric motors are cheap, efficient, and capable of handling high voltages. Judged in these terms, gallium oxide could be the best material yet, according to recent work by ­Flosfia [ut-ec.co.jp], a startup in Kyoto.

That’s because silicon—the incumbent material for making diodes and transistors for the power electronics market—is cheap but not very efficient. And although this weakness is addressed by devices made from silicon carbide [ieee.org] and gallium nitride [ieee.org], both have had limited commercial success due to high prices. Flosfia’s diodes are already performing more efficiently than those made from SiC and GaN.

The superiority of these gallium oxide devices stems from the material’s approximately 5–electron-volt bandgap—way higher than that of gallium nitride (about 3.4 eV) or silicon carbide (about 3.3 eV). Bandgap is a measure of the energy required to kick an electron into a conducting state. A bigger bandgap enables a material to withstand a stronger electric field, making it possible to use a thinner device for a given voltage. That’s a big deal because the thinner the device, the lower its resistance, and thus the more efficient it is.

Gallium oxide devices do not excel in all areas. Their Achilles’ heel is poor thermal conductivity. “When you make a high-power device, you need to have a good thermal conductivity to extract the heat out of the device,” explains Hong Lin, senior market and technology analyst at Yole Développement [www.yole.fr] in Lyon, France.

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