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Streszczenie:
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.

Streszczenie:
Cross-sectional transmission electron microscopy studies often reveal a-type dislocations located either below or above the interfaces in
InGaN/GaN structures deposited along the [0001] direction. We show that these dislocations do not emerge during growth but rather are a
consequence of the stress state on lateral surfaces and mechanical processing, making them a post-growth effect. In cathodoluminescence mapping, these defects are visible in the vicinity of the edges of InGaN/GaN structures exposed by cleaving or polishing. Finite element cal-culations show the residual stress distribution in the vicinity of the InGaN/GaN interface at the free edge. The stress distribution is discussed in terms of dislocation formation and propagation. The presence of such defects at free edges of processed devices based on InGaN layers may have a significant negative impact on the device performance.

Słowa kluczowe:
Luminescence ,Transmission electron microscopy ,Focused ion beam ,Semiconductor materials ,Epitaxy ,Crystal structure ,Crystal lattices ,Crystallographic defects,Mechanical stress,X-ray diffraction