Electrical excitation of N-polar GaN produces terahertz radiation at room temperature

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).