Proton Irradiation Effects in MOCVD Grown β-Ga₂O₃ and ε-Ga₂O₃ Thin Films

Abstract

Gallium oxide (Ga2O3) with robust bonding is advantageous for space applications, but its radiation hardness dependent on the crystalline phases has not been reported yet. Herein, the proton irradiation effects on $\beta $ -Ga2O3 and $\varepsilon $ -Ga2O3 epitaxial films grown by metal–organic chemical vapor deposition (MOCVD) have been observed at 100 MeV with proton fluences up to $1\times 10^{{11}}$ cm $^{-{2}}$ . The film crystallinity, surface quality, optical property, and defect concentration were measured from Ga2O3 with and without proton irradiation. Additionally, the metal–semiconductor–metal (MSM)-type photodetectors were constructed on the non-irradiated and proton-irradiated $\beta $ -/ $\varepsilon $ -Ga2O3 thin films to investigate radiation damage of photodetection performance. Although the proton irradiation may generate some possible irradiation defects (such as self-trapped holes or vacancies) in Ga2O3 thin films to degrade their photoelectric properties, the $\beta $ -/ $\varepsilon $ -Ga2O3-based photodetectors could still detect the solar-blind light signal sensitively. $\beta $ -Ga2O3 and $\varepsilon $ -Ga2O3 are materials for semiconductor devices regarding future space applications for their favorable resistance to radiation.