A terahertz device works at room temperature with safe materials. It could make wireless networks faster. Find out how it could change 6G.
Researchers at Nagoya University in Japan have created a room-temperature resonant tunnel diode (RTD) using only Group IV semiconductor materials—a first of its kind. This breakthrough opens the door for large-scale use of terahertz wireless components, which could deliver faster data speeds, higher network capacity, and better energy efficiency. Using only non-toxic materials also makes production more sustainable.
The RTD operates at around 27°C, overcoming a key limitation of previous Group IV RTDs that worked only at extremely low temperatures near -263°C, which made them impractical for consumer electronics or wireless systems. The device relies on a double-barrier structure, where electrons or holes tunnel through semiconductor layers only a few atoms thick. This structure enables negative differential resistance, allowing the diode to sustain high-frequency oscillations that would otherwise decay due to electrical losses.
The breakthrough was achieved by introducing hydrogen gas during the layer formation process. Researchers tested three scenarios: applying hydrogen to both GeSiSn and GeSn layers, applying no hydrogen, and applying hydrogen only to the GeSn layers. The final approach produced the most uniform and well-ordered double-barrier structure, preventing unwanted layer mixing and defects. Reducing these defects is critical, as they create leakage paths that block the negative differential resistance needed for RTD operation.
Previously, RTDs used InGaAs-based Group III-V materials containing rare and toxic elements like indium and arsenic. Achieving the high-speed, large-volume data transfer required for next-generation wireless networks has long been a challenge. Terahertz wireless communication, using electromagnetic waves that oscillate a trillion times per second, offers ultra-fast transmission but has faced significant technical hurdles before it can be used in consumer applications.
This room-temperature, non-toxic RTD could enable broader use of terahertz semiconductor devices, supporting faster, more energy-efficient wireless systems and paving the way for future 6G networks.
