Ti- And Fe-Related Charge Transition Levels In Beta-Ga2o3

Deep-level transient spectroscopy measurements on beta-Ga2O3 crystals reveal the presence of three defect signatures labeled E2a,E2, and E3 with activation energies at around 0.66eV, 0.73eV, and 0.95eV below the conduction band edge. Using secondary ion mass spectrometry, a correlation between the defect concentration associated with E3 and the Ti concentration present in the samples was found. Particularly, it is found that E3 is the dominant Ti-related defect in beta-Ga2O3 and is associated with a single Ti atom. This finding is further corroborated by hybrid functional calculations that predict Ti substituting on an octahedral Ga site, denoted as TiGaII, to be a good candidate for E 3. Moreover, the deep level transient spectroscopy results show that the level previously labeled E2 and attributed to Fe substituting on a gallium site (Fea) consists of two overlapping signatures labeled E2a and E2b. We tentatively assign E2a b to Fe substituting for Ga on a tetrahedral or an octahedral site, respectively. Published under license by AIP Publishing.