Dose-Dependent γ-Ray Irradiation Damage Effects in β-Ga ₂ O ₃ Solar-Blind Deep Ultraviolet Photodetector

This study investigates the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $</tex-math> </inline-formula>-ray irradiation dose-dependent radiation damage effects in Ti/Au-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $</tex-math> </inline-formula>-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>-Ti/Au metal-semiconductor-metal (MSM) solar-blind photodetectors. By analyzing the photoresponse under varying cumulative irradiation doses, we systematically examine the influence of total ionizing dose (TID) on the photodetector, aiming to evaluate the degradation behavior and underlying mechanisms. At low irradiation doses, the majority carrier removal effect in Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>, induced by Compton scattering-generated defects that trap or compensate carriers, leads to a reduction in dark current. In contrast, high-dose irradiation promotes the formation of deep-level complex defects through the combination of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {O}}$</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {Ga}}$</tex-math> </inline-formula>, triggering nonradiative recombination and leading to a sharp increase in dark current. Numerical simulations based on technology computer-aided design (TCAD) were employed to model the irradiation-induced defects, and the results show good agreement with experimental observations, further confirming the defect evolution and carrier dynamics under different TID levels. Furthermore, X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to analyze the microscopic structural changes and degradation mechanisms induced by TID irradiation. This work provides a theoretical foundation for the application of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $</tex-math> </inline-formula>-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> solar-blind photodetectors in extreme radiation environments.