Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 67: Poster: Oxide, Insulator and Semiconductor Surfaces
O 67.10: Poster
Wednesday, March 20, 2024, 18:00–20:00, Poster C
Structure and Stability of Al-alloyed β-Ga2O3(100) surfaces — •Ming-Chao Kao1,4, Lukas Paul Schewe2, Arub Akhtar3, Jana Rehm3, Saud Bin Anooz3, Zbigniew Galazka3, Andreas Popp3, Jan Ingo Flege2, Vedran Vonk1, and Andreas Stierle1,4 — 1Centre for X-ray and Nanoscience, Deutsches Elektronen-Synchrotron, Hamburg, Germany — 2Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus, Germany — 3Leibniz-Institut für Kristallzüchtung , Berlin, Germany — 4Department of Physics, University of Hamburg
β-Ga2O3 (GaO) holds great promise in high-power applications. GaO is predicted to outperform the leading technologies based on SiC and GaN due to a three times higher calculated critical field strength. It has been identified that alloying with Al results in an almost linear increase in the bandgap between Ga2O3 (4.85eV) and Al2O3 (7eV). A critical issue in the bandgap engineering of GaO is maintaining reasonable electron mobility, which is low for the pure material (150cm2/V/S). This project aims to explore GaO by Al alloying, which allows tunable wide bandgaps for engineering material properties and at the same time maintains excellent crystal quality. PXRD and their Rietveld refinement on several AlGaO crystals indicate a preferential ordering of Al and Ga over octahedral and tetrahedral sites. The results of an SXRD study using synchrotron radiation addressing the surface structure of β-AlxGa2−xO3(100) substrates with x=0−0.25. Our results indicate that the GaO(100) surface is nearly bulk terminated and remains smooth up to 800∘C and 10−5mbar of molecular oxygen.
Keywords: crystal truncation rod (CTRs); SXRD; beta-Ga2O3; oxide substrate; semiconductor material