Chinese scientists achieve breakthrough in field of high-frequency transistors

Chinese scientists have achieved a major breakthrough in high-frequency transistor technology, marking an important step towards next-generation electronics, as reported by TV BRICS' partner, Science and Technology Daily.

Researchers from the Institute of Metal Research of the Chinese Academy of Sciences (IMR CAS), in collaboration with several research institutions, have successfully developed the world's first silicon–graphene–germanium barrier transistor. The device achieved record-breaking current gain and cut-off frequency. This innovation paves the way for transistors capable of operating in the terahertz (THz) range, which are essential for future 6G systems and ultra-fast sensing technologies.

As 5G deployment continues to expand and research into 6G accelerates, demand is growing for transistors capable of operating at frequencies above 1 terahertz (THz) to support Internet of Things (IoT) devices, intelligent sensors and high-speed communication systems.

In recent years, vertical two-dimensional-base transistors using two-dimensional materials such as graphene as the base layer have shown considerable promise. The research team proposed a novel device architecture. Using chemical vapour deposition (CVD), they grew a single-crystal graphene layer on a germanium substrate and then precisely stacked a single-crystal silicon thin film, creating a silicon–graphene–germanium vertical heterostructure. The resulting design exploits asymmetric Schottky barriers at the graphene–silicon and graphene–germanium interfaces, combined with the quantum capacitance effect of graphene to modulate the work function (the energy required to remove an electron from a solid or liquid into a vacuum – editor's note).

This design enables a much greater current variation on the germanium side than on the silicon side, achieving a common-emitter current gain of up to 1.8 × 10⁷ – the highest value ever reported for any transistor. In radio-frequency (RF) measurements, the transistor achieved an intrinsic cut-off frequency of 132 GHz, outperforming all previously reported graphene-based vertical transistors.

This work lays the foundation for the practical application of barrier transistors in RF and terahertz communications and creates new technological pathways for future Internet of Things systems, 6G sensing technologies and ultra-fast signal processing.