Pulsed X-Ray Detector Based on an Unintentionally-Doped High Resistivity ε-Ga₂O₃ Film

Abstract

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) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -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 ~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.0\,\,\times 10^{6}$ </tex-math></inline-formula> nC/( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {Gy}\cdot \text {cm}^{3}$ </tex-math></inline-formula> ) 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ga2O3 film for ultrafast X-ray detection.