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.

In this paper, the electrical and ultraviolet optoelectronic properties of the interdigitated finger geometry β-Ga2O3 photodetector were investigated from the temperature of 40 K to 300 K. Under different light illumination conditions, when the temperature increased from 40 K to 300 K, the maximum current of the β-Ga2O3 photodetector was obtained around 180 K, which is related to the carrier mobility of β-Ga2O3. Under 365-nm illumination, when the temperature increased from 40 K to 300 K, the photo-to-dark current ratio (PDCR) of the β-Ga2O3 photodetector increased by 924%. Under 254-nm illumination, the PDCR decreased by 87%. Besides, the temperature point corresponding to the photoresponse peak under 365-nm illumination moved to the right under 254-nm illumination, indicating that the photodetector had a redshift at low temperature. Moreover, the fast photoresponse time under 365-nm and 254-nm illumination decreased when the temperature increased. This indicated that the defect concentration of Ga2O3 decreased gradually as the temperature increased, leading to the faster response time of the photodetector.