Unravelling the surface structure of β-Ga2O3 (100)

The present work is on a comprehensive surface atomic structure investigation of beta-Ga2O3 (100). The beta-Ga2O3 single crystal was studied by a structural model system in the simulations and in situ characterization via X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and X-ray photoelectron diffraction (XPD) allowed for probing the outermost layers' properties. In situ XPD characterization allows for the collection of valuable element-specific short-range information from the beta-Ga2O3 surface, and the results were compared to a systematic and precise multiple scattering simulation approach. The experiments, characterizations, and simulations indicated strong evidence of considerable structural variations in the interatomic layer's distances. Such atomic displacement could clarify the electronic phenomena observed in theoretical studies. The comparison between experimental and theoretical XPD results involving multiple scattering calculations indicated that the beta-Ga2O3 surface has two possible terminations. The best fits to the photoelectron diffraction curves are used to calculate the interplanar relaxation in the first five atomic layers. The results show good agreement with previous density functional theory calculations, establishing XPD as a useful tool for probing the atomic structure of oxide surfaces.

Automated summary

In this study, a comprehensive investigation of the surface atomic structure of beta-Ga2O3 (100) was conducted using simulations and in situ characterizations. The results revealed significant structural variations in the interatomic layer, which may explain the observed electronic phenomena in theoretical studies. Comparison between experimental and theoretical results indicated that the beta-Ga2O3 surface has two possible terminations.