Regensburg 2025 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Crystal Structure Defects / Real Structure / Microstructure

KFM 15.6: Talk

Thursday, March 20, 2025, 11:15–11:30, H9

Phase modifications in Beta-Gallium Oxide via Focus ion beam irradiations — •Umutcan Bektas, Nico Klingner, Paul Chekhonin, Fabian Ganss, Rene Hübner, Maciej Oskar Liedke, and Gregor Hlawacek — Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

Gallium oxide (Ga2O3) is a highly versatile material with power electronics, optoelectronics, and battery technologies applications. Among its polymorphs, monoclinic β-Ga2O3 is the most chemically and thermally stable phase. However, managing the metastable polymorph phases remains challenging, and the fabrication technology for nanoscale structures is still under development. We aim better to understand the polymorph conversion mechanisms under ion irradiation. In this study, we investigate the β-Ga2O3 samples irradiated with different ions and fluences, together with α- and κ-Ga2O3 thin films. Focused ion beam (FIB) irradiation was used to locally modify the samples under controlled conditions by varying the ion beam current, size, spacing, scan type, and ion species. The irradiated regions were characterized using electron backscatter diffraction and transmission electron microscopy to analyze structural changes. Broad beam irradiation experiments were complemented by positron annihilation spectroscopy methods to determine defect types and concentrations. Initial results indicate that spatially resolved polymorph transitions can be achieved using FIB irradiation. In addition, the defect size and concentration were found to depend on the polymorph and the implanted ion species, providing critical into defect engineering in Ga2O3.

Keywords: Gallium Oxide; Defects in Gallium Oxide; Focus ion beam; TEM; EBSD