Clarifying the atomic origin of electron killers in β-GaO from the first-principles study of electron capture rates

The emerging wide bandgap semiconductor -GaO has attracted great interest due to its promising applications for high-power electronic devices and solar-blind ultraviolet photodetectors. Deep-level defects in -GaO have been intensively studied towards improving device performance. Deep-level signatures E , E , and E with energy positions of 0.55-0.63, 0.74-0.81, and 1.01-1.10 eV below the conduction band minimum have frequently been observed and extensively investigated, but their atomic origins are still under debate. In this work, we attempt to clarify these deep-level signatures from the comparison of theoretically predicted electron capture cross-sections of suggested candidates, Ti and Fe substituting Ga on a tetrahedral site (Ti and Fe) and an octahedral site (Ti and Fe), to experimentally measured results. The first-principles approach predicted electron capture cross-sections of Ti and Ti defects are 8.56 × 10 and 2.97 × 10 cm, in good agreement with the experimental values of E and E centers, respectively. We, therefore, confirmed that E and E centers are indeed associated with Ti and Tidefects, respectively. Whereas the predicted electron capture cross-sections of Fe defect are two orders of magnitude larger than the experimental value of the E , indicating E may have other origins like Cand Ga, rather than common believed Fe