TY - GEN A1 - Kao, Ming-Chao A1 - Schewe, Lukas Paul A1 - Akhtar, Arub A1 - Rehm, Jana A1 - Bin Anooz, Saud Bin A1 - Galazka, Zbigniew A1 - Popp, Andreas A1 - Flege, Jan Ingo A1 - Vonk, Vedran A1 - Stierle, Andreas T1 - Structure and Stability of Al-alloyed β-Ga2O3(100) surfaces T2 - Verhandlungen der DPG, Berlin 2024 N2 - 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. KW - high-power applications KW - bandgap engineering KW - crystal quality KW - X-ray diffraction Y1 - 2024 UR - https://www.dpg-verhandlungen.de/year/2024/conference/berlin/part/o/session/67/contribution/10 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Kao, Ming-Chao A1 - Schewe, Lukas Paul A1 - Akhtar, Arub A1 - Vlad, Alina A1 - Keller, Thomas F. A1 - Henkel, Karsten A1 - Anooz, Saud Bin A1 - Popp, Andreas A1 - Galazka, Zbigniew A1 - Flege, Jan Ingo A1 - Stierle, Andreas A1 - Vonk, Vedran T1 - Surface termination of β-Ga₂O₃(100) as-cleaved single crystals T2 - Applied physics letters N2 - The surface of β-Ga₂O₃ single crystals cleaved along their (100) plane is investigated using surface x-ray diffraction and atomic force microscopy. The results show the surface to consist of a single, so-called B-termination, which means that the crystal cleaves at planes formed by edge-sharing oxygen octahedra, thereby breaking the longest and weakest Ga–O bonds. Refinement of the atomic positions results in small displacements from the bulk structure, at most approximately 0.01 Å. Atomic force microscopy suggests that relatively large terraces form together with steps of half the a-axis length of approximately 0.6 nm, which means that terraces have the same atomic termination, related by the crystal symmetry. These results are important as a fundamental property of β-Ga₂O₃ when processed or used in various semiconductor applications. KW - X-ray KW - Gallium oxide Y1 - 2026 U6 - https://doi.org/10.1063/5.0309937 SN - 0003-6951 VL - 128 IS - 7 SP - 1 EP - 5 PB - AIP Publishing CY - Melville, NY ER -