Pulsed X-Ray Detector Based on an Unintentionally-Doped High Resistivity ϵ-GaO Film

Gallium Oxide (Ga2O3), an emerging ultra-wide band gap semiconductor, has drawn great attention for application in radiation detection. In this letter, ultrafast X-ray detectors have been fabricated using a high resistivity unintentionally-doped (UID) ϵ-Ga2O3 film grown on sapphire by metal-organic chemical vapor deposition (MOCVD). The detector featuring a lateral metal-semiconductor-metal (MSM) structure exhibited a low dark current < 2 nA at 100 V and its sensitivity was as high as 28.6 nC/Gy or 1.0 × 106 nC/(Gy·cm3) at 40 V and an X-ray dose rate of 0.383 Gy/s. A stable and repeatable transient response was observed for the detectors under switching X-ray illumination. Furthermore, the detector achieved a pulsed X-ray detection with 50 ns in full width and its time resolution was revealed to be 7.1 ns. These results imply the great potential of the MOCVD-grown high-resistivity UID ϵ-Ga2O3 film for ultrafast X-ray detection.