Cornell University produces first working transistor with 7 eV bandgap

Summary

Researchers at Cornell University demonstrated the first functional transistor made from a silicon-doped aluminum gallium oxide semiconductor with a bandgap exceeding 7 eV. This device surpasses the previous 6 eV record and exhibits 100 million times higher conductivity compared to existing materials in the same class.

Why it matters

Wide bandgap semiconductors can withstand stronger electric fields. This property is critical for electric vehicles, aircraft propulsion systems, and grid infrastructure, where efficiency losses directly impact cost and range. The fact that the material was grown on sapphire, which is already produced on an industrial scale, offers a more credible path to manufacturing compared to many ultra-wide bandgap candidates that have remained confined to the lab.

Highlights

• 100 million-fold increase in conductivity compared to previously reported >6 eV materials
• First functional field-effect transistor (AlphaFET) demonstrated in the >7 eV bandgap class
• Grown on sapphire, which is already produced at commercial scale

Critical take

The team admits that "further work is needed to make the device practical." A single laboratory-scale transistor on a thin film is far from the high-current, high-temperature power devices that would truly make a difference for electric vehicles or aircraft. Additionally, the 100 million-fold increase in conductivity is measured against a very small and poorly characterized baseline, which exaggerates the apparent magnitude of the progress.