Terahertz waves sit between microwaves and infrared light. They can help reveal the properties of materials and are being explored for imaging, sensing and high-speed wireless links, but compact electrical sources remain difficult to develop. Researchers from the Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, and the University of Electronic Science and Technology of China measured a terahertz signal from a pulsed gallium nitride transistor at room temperature. Its N-polar structure places the active channel close to a nanoscale surface grating.

The signal grew with stronger electric fields and longer electrical pulses. The broad spectra are consistent mainly with heating caused by the current; the measurements do not establish a distinct plasmon resonance. This distinction gives researchers a clearer starting point for separating heat-driven emission from other possible effects. Runxian Xing and colleagues have established a platform for further tests that calibrate the emitted signal, examine its polarization and vary the gate voltage. Such studies could inform future compact systems for spectroscopy, imaging and non-destructive inspection.

The work entitled “Room-temperature terahertz emission from N-polar GaN grating-gate high-electron-mobility transistors” was published in Frontiers of Optoelectronics (published on October12, 2026).
DOI: 10.2738/foe.2027.0002