Effects of 1 MeV Electron Irradiation on β-Ga₂O₃ Photodetectors

Abstract

In this paper, the electrical and ultraviolet optoelectronic properties of the interdigitated finger geometry β-Ga2O3 photodetector were investigated before and after 1 MeV electron irradiation. Under the dark condition, the voltage at which the minimum current was located shifted from 0 V to −9.5 V after the electron irradiation. As the fluence increased from 5.0 × 1013 cm−2 to 1.0 × 1015 cm−2, the current at the voltage of 3 V of the β-Ga2O3 photodetector increased from 0.047 nA to 0.121 nA. The negative deviation of the minimum current was related to the positive charge trap caused by electron irradiation, while the improvement of the current was related to the fact that the electron irradiation produced a large number of electron -hole pairs. Under 365-nm illumination, the current at the voltage of 3 V of the β-Ga2O3 photodetector increased from 0.199 nA to 0.898 nA, as the fluence increased from 5.0 × 1013 cm−2 to 5.0 × 1014 cm−2; then, it dropped to 0.779 nA when the fluence reached 1.0 × 1015 cm−2. The increase of the current was due to the increase of defects generated by the electron irradiation under 365-nm illumination. Also, the decline of the current at the fluence of 1.0 × 1015 cm−2 may be caused by the quenching effect. Under 254-nm illumination, the current at the voltage of 3 V of the β-Ga2O3 photodetector dropped from 78.566 nA to 19.362 nA after the electron irradiation. This change was due to the lattice distortion and the reduction of the defect energy. However, as the fluence of the irradiation increased, the current increased gradually. This may be related to the increase of defects excited by electrons.

Engineered interface states and optical absorption of β-Ga2O3/4H-SiC heterojunctions by irradiation-induced oxygen defects from first-principles

“…The experiments demonstrated that after proton irradiation, the number of oxygen vacancies increased significantly and increased the transportation of carriers’ transformation. Wang et al 16 investigated the effects of 1 MeV electron irradiation on β-Ga 2 O 3 photodetectors and found that the photodetector current increased with the irradiation fluence. They also reported the current of the β-Ga 2 O 3 photodetector decreases with decreasing vacancies under 254 nm illumination.…”