Highly Reliable and Sensitive Solar-Blind Ultraviolet and X-Ray Detector Based on ALD Deposited Amorphous Ga₂O₃

Abstract

This study demonstrates a metal-semiconductor-metal (MSM) type photodetector based on 50 nm amorphous Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film using the atomic layer deposition (ALD) technique that can provides effective detections at both solar-blind and X-ray lights. The detector exhibits stable performances at high temperature (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150~^{\circ }$ </tex-math></inline-formula>C) in the air, characterized by a low dark current (<0.1 nA), high photo-to-dark current ratio (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gt 10^{{5}}\text {)}$ </tex-math></inline-formula>, and fast responses (rising/decaying times of 0.53/0.13 s), respectively. Meanwhile, the detector shows the high sensitivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$952~\mu $ </tex-math></inline-formula>C Gy<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {air}}^{-{1}}$ </tex-math></inline-formula> cm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}}\text {)}$ </tex-math></inline-formula> and ultra-low detection limit (11.23 nGy<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</sub>s<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}\text {)}$ </tex-math></inline-formula> in X-ray detection, which is among the highest values reported in Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin film photodevices to the best of authors’ knowledge. The superior capabilities can be ascribed to the restricted oxygen vacancies during the ALD process. These results indicate that the Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>-based detector has great potential for applications in security system and irradiation exploration in harsh environments.