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Nagoya University Produces Gallium Oxide pn Diodes with Enhanced Current Capacity

By Amelia Earhart | TOKYO – 2025/09/01 12:41:21

Researchers at Japan’s Nagoya University have announced a critically importent advancement in gallium oxide (Ga₂O₃) semiconductor technology, potentially paving the way for more energy-efficient electronic devices. The team has successfully created functional pn diodes using gallium oxide, overcoming previous limitations in producing stable p-type layers.This innovation promises improved semiconductors and more efficient devices, with the new diodes exhibiting twice the electrical current capacity of their predecessors (Naohiro Shimizu et al, ‘p-type layer formation study for Ga₂O₃ by employing Ni ion implantation with two-step oxygen plasma and thermal annealing‘, Journal of Applied Physics (2025), 138(6). DOI: 10.1063/5.0282789).

Overcoming the P-Type Layer Challenge

The primary hurdle in utilizing gallium oxide for semiconductors has been the difficulty in creating stable p-type layers. gallium oxide’s crystal structure readily accommodates atoms for n-type layers but resists those needed for p-type layers. Prior attempts to force these atoms into the structure either failed or required temperatures that damaged the material, hindering the practical submission of gallium oxide.

To circumvent this issue, the Nagoya University researchers employed a novel method involving the implantation of nickel atoms into the gallium oxide layer. The material than underwent a two-step heating process: first at 300°C with activated oxygen radicals (using a proprietary plasma treatment), followed by heating at 950°C in oxygen gas. This process effectively converted the embedded nickel into nickel oxide and integrated it into the gallium oxide crystal structure.

“Since this method uses standard industrial equipment and processes, it can be scaled up for mass production,”