For most electrical devices, the electric current and voltage must be converted to suit the object being powered—be it a mobile phone or electric vehicle—using a transformer. This essential power conversion step does however result in energy loss. Gallium nitride (GaN) and other wide band gap materials can substantially reduce energy loss, but until now have been cost-prohibitive for use in power conversion electronics.

Researchers at Leti found a workaround that involves covering a silicon wafer with a very thin and uniform layer of GaN using CVD. Conventional silicon microelectronics fabrication techniques can then be used on the wafer, keeping costs down. The researchers also made a GaN transistor that only conducts electricity when it receives an on/off command, overcoming a safety hurdle that plagued previous versions of the transistor, which were always conductive.

The 650-volt transistor produced has already been transferred to several manufacturers, including in the automotive industry, where it could one day be used in electric vehicle charging terminals.