High-energy x-ray radiation effects on the exfoliated quasi-two-dimensional β-Ga 2 O 3 nanoflake field-effect transistors.

The effects of x-ray irradiation on the mechanically exfoliated quasi-two-dimensional (quasi-2D) β-Ga ₂ O ₃ nanoflake field-effect transistors (FETs) under the condition of biasing voltage were systematically investigated for the first time. It has been revealed that the device experienced two stages during irradiation. At low ionizing doses (<240 krad), the device performance is mainly influenced by the photo-effect and the subsequent persistent photocurrent (PPC) effect as a result of the pre-existing electron traps (e-trap) in the oxides far away from the SiO ₂ /β-Ga ₂ O ₃ interface. At larger doses (>240 krad), the device characteristics are dominated by the radiation-induced structural or compositional deterioration. The newly-generated e-traps are found located at the SiO ₂ /β-Ga ₂ O ₃ interface. This study shed light on the future radiation-tolerant device fabrication process development, paving a way towards the feasibility and practicability of β-Ga ₂ O ₃ -based devices in extreme-environment applications.