Partners

Abstract:
The microscopic fate of dopants introduced under nonequilibrium conditions remains largely unresolved in wide-band gap oxides. Using temperature-dependent N K-edge X-ray absorption spectroscopy, we directly resolve the local bonding configuration of implanted nitrogen in (100) β-Ga2O3. The spectra are dominated by a sharp π* resonance characteristic of N≡N bonding that systematically intensifies upon annealing, providing a direct spectroscopic fingerprint of molecular nitrogen formation. First-principles calculations and multiple-scattering simulations reproduce these spectral features and identify molecular N2 as the dominant dopant state. Rather than forming substitutional acceptors, implanted nitrogen evolves toward N2-like configurations stabilized in defect-rich environments associated with local β→γ-like structural motifs. This behavior reflects a thermally driven reconfiguration of nitrogen within the damaged layer. These results demonstrate that dopant incorporation can proceed via molecularization pathways that bypass conventional substitutional doping, providing a general mechanism for dopant deactivation under nonequilibrium incorporation conditions in oxides.