Structural stability of beta-Ga2O3 under ion irradiation

beta-Ga2O3 was suggested to have excellent irradiation hardness which makes beta-Ga2O3-based devices extremely attractive for nuclear and space applications. To discern the fundamental nano-scale structural changes with irradiation, an in situ irradiation experiment in a transmission electron microscope was carried out using 400 keV Ar ions of fluences up to 8 x 10(15) cm(-2) (equivalent to four displacements per atom). Contrary to previous works, which indicate a phase transition of beta-Ga2O3 into the kappa polymorph, the beta-Ga2O3 structure was found to remain intact throughout except for (i) anisotropic lattice distortions, which are most significant at low levels of irradiation, and (ii) the appearance of additional weak reflections above 2 dpa irradiation. The origin of the extra reflections is discussed. (C) 2022 Author(s).