Influence of 300 MeV High-Energy Proton Irradiation on β-Ga₂O₃ Solar-Blind Ultraviolet Photodetector

The influence of 300 MeV high-energy proton irradiation on β-Ga₂O₃ solar-blind ultraviolet photodetectors was investigated for space optoelectronics applications. The photoelectric performance of the photodetectors was measured before and after proton irradiation with a fluence of up to 5×10¹² p/cm². Both photocurrent and dark current increased significantly, but the photo-to-dark current ratio (PDCR) remained above 10³ due to a larger rise in photocurrent. The response time increased after proton irradiation, likely due to radiation-induced defects that affected carrier transport. The decrease in the power law exponent of the current–voltage characteristics suggested an increase in internal defects within the β-Ga₂O₃ film. Simulation using stopping and range of ions in matter revealed that protons passed through the β-Ga₂O₃ film without being trapped. An X-ray diffraction analysis showed no detectable structural changes in the β-Ga₂O₃ film. An X-ray photoemission spectroscopy indicated an increased concentration of oxygen vacancies. These oxygen vacancies were likely responsible for the observed increase in both photocurrent and dark current, as they could act as trap states, enhancing carrier generation and reducing the overall barrier height. The excellent radiation hardness of β-Ga₂O₃ solar-blind ultraviolet photodetectors demonstrated the potential for space optoelectronics applications.