【Device Papers】Gallium vacancy displacement damage induced by 1 MeV neutron irradiation in β-Ga₂O₃ solar-blind photodetector

      Researchers from the Zhejiang Sci-Tech University have published a dissertation titled "Gallium vacancy displacement damage induced by 1 MeV neutron irradiation in β-Ga₂O₃ solar-blind photodetector" in The European Physical Journal Special Topics.

Abstract

      Due to its ultra-wide bandgap, large density and high atomic displacement threshold energy, β-Ga₂O₃ demonstrates excellent radiation hardness and holds significant potential for applications in the aerospace industry. In this study, we explored the impact of neutron irradiation damage on β-Ga₂O₃ photodetectors with two different structures: Schottky-type and metal–semiconductor–metal (MSM) Ohmic-type. Following neutron irradiation, the dark current, photocurrent, and photoresponsivity of the photodetectors significantly decreased, and the photoresponse speed slowed down. These effects can be attributed to displacement damage, primarily caused by gallium vacancies induced by neutron irradiation, which reduces carrier mobility and lowers carrier concentration through compensation mechanisms. Under an applied bias of 5 V and illuminated by 254 nm light with an intensity of 1000 μW/cm², the photoresponsivity of the Schottky-type β-Ga₂O₃ photodetector decreased from 589.73 to 573.03 A/W, with a minimal attenuation rate of 2.83% after neutron irradiation. Both X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) analysis confirmed that neutron irradiation caused the breakage of covalent bonds in β-Ga₂O₃ and led to an increased presence of gallium vacancy defects as a result of displacement damage. Furthermore, Hall effect measurements indicated that neutron irradiation affected carrier mobility to a greater extent than carrier concentration in the β-Ga₂O₃ material system. This work not only provides important insights into the effect of neutron irradiation on the photoelectric performance and material physical properties of β-Ga₂O₃ based solar blind photodetectors but also highlights that Schottky-type photodetector exhibit the best resistance to neutron irradiation under positive bias.

DOI：

https://doi.org/10.1140/epjs/s11734-024-01387-w