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Silicon (Si) semiconductors are widely used as particle detectors; however, their long-term operation is constrained by performance degradation in high-radiation environments. Researchers at University of Tsukuba have demonstrated real-time, two-dimensional position detection of individual charged particles using a gallium nitride (GaN) semiconductor with superior radiation tolerance.

Tsukuba, Japan—Silicon (Si)-based devices are widely used in electrical and electronic applications; however, prolonged exposure to high radiation doses leads to performance degradation, malfunction, and eventual failure. These limitations create a strong demand for alternative semiconductor materials capable of operating reliably in harsh environments, including high-energy accelerator experiments, nuclear-reactor containment systems, and long-duration lunar or deep-space missions.

Wide-bandgap semiconductors, characterized by strong atomic bonding, offer the radiation tolerance required under such conditions. Among these materials, gallium nitride (GaN)—commonly employed in blue light-emitting diodes and high-frequency, high-power electronic devices—has not previously been demonstrated in detectors capable of two-dimensional particle-position sensing for particle and nuclear physics applications.

In this study, a vertical GaN particle detector with a 100-µm pixel size was fabricated, enabling real-time two-dimensional position detection of individual alpha particles and xenon (Xe) heavy ions. The detector exhibited stable operation at radiation levels approximately an order of magnitude higher than those tolerated by conventional Si‑based detectors. In addition, the availability of large-area, high-quality GaN wafers provides a viable route toward scalable detector systems.

These results demonstrate that two-dimensional particle-beam position sensing remains feasible under extremely high radiation doses. This advance is expected to accelerate the development of high-energy accelerator facilities, space-exploration instrumentation, nuclear-power monitoring systems, and radiation-based medical diagnostics.

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This work was financially supported by JSPS KAKENHI Grant No. 23H01863, the TIA "Kakehashi" collaborative research program, the TRiSTAR program under the Strategic Professional Development Program for Young Researchers by MEXT, and the "Advanced Research Infrastructure for Materials and Nanotechnology in Japan (ARIM)" project of MEXT (No. JPMXP1223BA0011).

Original Paper

Title of original paper:

GaN radiation detectors with low-gain avalanche diode structure

Journal:

Japanese Journal of Applied Physics

DOI:

10.35848/1347-4065/ae2dad

Correspondence

Associate Professor OKUMURA Hironori
Institute of Pure and Applied Sciences, University of Tsukuba

Related Link

Institute of Pure and Applied Sciences