Self-powered fast-response X-Ray detectors based on vertical GaN p-n Diodes

GaN offers an excellent potential for fabricating X-ray detectors, taking advantage of its superior material properties and well-developed manufacturing technologies. In this letter, we demonstrated a self-powered fast-response X-ray detection using GaN-based vertical p-n diodes grown on a bulk GaN substrate. Attributed to the high crystalline quality achieved by homoepitaxy, the fabricated photodiodes exhibited an excellent rectification behavior, and therefore, a strong photovoltaic response to X-ray illumination when biased at 0 V. The transient X-ray detection analysis revealed that the self-powered detectors have a relatively short response time (<20 ms) and a good linear response to the X-ray incident dose rate with a high specific sensitivity of 170 nC·Gy^-1·cm^-2.