On the presence of Ga2O sub-oxide in high-pressure water vapor annealed AlGaN surface by combined XPS and first-principles methods
| Autor: | Mary Clare Sison Escaño, Mutsunori Uenuma, Hirokuni Tokuda, Zenji Yatabe, Melanie David, Yukiharu Uraoka, Joel T. Asubar, Masahiko Tani, Masaaki Kuzuhara |
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| Rok vydání: | 2019 |
| Předmět: |
Surface (mathematics)
Materials science High pressure water Binding energy Analytical chemistry Oxide General Physics and Astronomy 02 engineering and technology Surfaces and Interfaces General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films chemistry.chemical_compound chemistry X-ray photoelectron spectroscopy Oxidation state Density functional theory 0210 nano-technology Water vapor |
| Zdroj: | Applied Surface Science. 481:1120-1126 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2019.03.196 |
| Popis: | We conducted X-ray photoelectron spectroscopy (XPS) and first-principles calculations based on density functional theory (DFT) to confirm the presence of Ga2O sub-oxide in high-pressure water vapor annealed AlGaN surface. We note that the Ga 3d XPS peak broadens and shifts towards higher binding energies, which suggests surface oxide formation. Deconvoluted Ga 3d XPS profiles between HPWVA-treated and reference samples reveal reasonable inclusion of Ga2O peak, suggesting formation of Ga2O sub-oxide. To theoretically confirm the presence of Ga2O, we calculated the Ga 3d core-level shift using initial state approximation. We obtained a 0.74 eV shift, in reasonable agreement with that of Ga2O. Moreover, based on the calculation of net charge on Ga using DFT, we also obtained a +1 oxidation state for Ga, indicating its existence in Ga2O form. By combining theory and experiment, therefore, we have explored the possibility of the formation of Ga2O sub-oxide, which may provide new avenues for obtaining highly stable operation in GaN-based devices. |
| Databáze: | OpenAIRE |
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