Effects of 1 MeV Electron Irradiation on β-Ga2O3 Photodetectors

In this paper, the electrical and ultraviolet optoelectronic properties of the interdigitated finger geometry beta-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 x 10(13) cm(-2) to 1.0 x 10(15) cm(-2), the current at the voltage of 3 V of the beta-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 beta-Ga2O3 photodetector increased from 0.199 nA to 0.898 nA, as the fluence increased from 5.0 x 10(13) cm(-2) to 5.0 x 10(14) cm(-2); then, it dropped to 0.779 nA when the fluence reached 1.0 x 10(15) 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 x 10(15) cm(-2) may be caused by the quenching effect. Under 254-nm illumination, the current at the voltage of 3 V of the beta-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.(C) 2021 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited.

Automated summary

This study investigated the electrical and ultraviolet optoelectronic properties of interdigitated finger geometry beta-Ga2O3 photodetector before and after electron irradiation. The results showed that electron irradiation caused shifts in minimum current voltage, increased current at 3V voltage, and changes in current under different illuminations. The increase of defects and electron-hole pairs were found to be the main factors affecting the optoelectronic properties of the photodetector.