Defect control in Gallium Oxide for next gen POWer electronics (GO-POW)

• Frodason, Ymir Kalmann; Varley, Joel B.; Johansen, Klaus Magnus H; Vines, Lasse & Van De Walle, Chris G. (2023). Migration of Ga vacancies and interstitials in β-Ga2 O3. Physical review B (PRB). ISSN 2469-9950. 107(2), s. 024109-1–024109-9. doi: 10.1103/PhysRevB.107.024109. Fulltekst i vitenarkiv
• Borgersen, Jon; Karsthof, Robert Michael; Rønning, Vegard; Vines, Lasse; Von Wenckstern, Holger & Grundmann, Marius [Vis alle 8 forfattere av denne artikkelen] (2023). Origin of enhanced conductivity in low dose ion irradiated oxides. AIP Advances. ISSN 2158-3226. 13(1), s. 015211-1–015211-5. doi: 10.1063/5.0134699. Fulltekst i vitenarkiv
• Ney, Verena; Henne, Bastian; de Souza, Mariano; Jantsch, Wolfgang; Johansen, Klaus Magnus Håland & Wilhelm, Fabrice [Vis alle 8 forfattere av denne artikkelen] (2023). Valence state, lattice incorporation, and resulting magnetic properties of Ni in Zn/Co-based magnetic oxides. Journal of Applied Physics. ISSN 0021-8979. 133(3). doi: 10.1063/5.0130731. Fulltekst i vitenarkiv
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2023). Trap-limited diffusion of Zn in β-Ga2 O3. PHYSICAL REVIEW MATERIALS. ISSN 2475-9953. 7(3), s. 1–8. doi: 10.1103/PhysRevMaterials.7.035401. Fulltekst i vitenarkiv
• Frodason, Ymir Kalmann; Krzyzaniak, Patryk Piotr; Vines, Lasse; Varley, Joel Basile; Van De Walle, Chris G. & Johansen, Klaus Magnus H (2023). Diffusion of Sn donors in β-Ga2O3. APL Materials. ISSN 2166-532X. 11(4), s. 041121-1–041121-8. doi: 10.1063/5.0142671. Fulltekst i vitenarkiv
• Langørgen, Amanda; Frodason, Ymir Kalmann; Karsthof, Robert Michael; Von Wenckstern, Holger; Jensen, Ingvild Julie Thue & Vines, Lasse [Vis alle 7 forfattere av denne artikkelen] (2023). Defect level in κ-Ga2O3 revealed by thermal admittance spectroscopy. Journal of Applied Physics. ISSN 0021-8979. 134(1), s. 015701-1–015701-6. doi: 10.1063/5.0150994. Fulltekst i vitenarkiv Vis sammendrag

  Defects in pulsed-laser deposition grown have been investigated using thermal admittance spectroscopy and secondary ion mass spectrometry (SIMS). A film was grown on either a tin-doped indium oxide or an aluminum-doped zinc oxide buffer layer on a sapphire substrate functioning as back contact layer in vertical diode structures. In both sample types, a distinct signature in the capacitance signal was observed in the temperature range of 150–260 K. The corresponding defect charge-state transition level, labeled ⁠, was found to exhibit an activation energy of 0.21 eV. Potential candidates for the level were investigated using a combination of SIMS and hybrid-functional calculations. SIMS revealed the main impurities in the sample to be tin, silicon, and iron. The hybrid-functional calculations predict the acceptor levels of substitutional iron to lie 0.7–1.2 eV below the conduction band minimum depending on Ga-site, making an unlikely candidate for the level. Furthermore, Si as well as Sn substituting on the sixfold coordinated Ga2 site and the fivefold coordinated Ga3 and Ga4 sites are all shallow donors in -⁠, similar to that of -⁠. Sn substituting on the fourfold Ga1 site is, however, predicted to have levels in the bandgap at 0.15 and 0.24 eV below the conduction band minimum, in accordance with the extracted activation energy for ⁠. Thus, we tentatively assign as the origin of the level.

• Seyidov, Palvan; Varley, Joel B.; Frodason, Ymir Kalmann; Klimm, Detlef; Vines, Lasse & Galazka, Zbigniew [Vis alle 10 forfattere av denne artikkelen] (2023). Thermal Stability of Schottky Contacts and Rearrangement of Defects in β-Ga2O3 Crystals. Advanced Electronic Materials. ISSN 2199-160X. doi: 10.1002/aelm.202300428. Fulltekst i vitenarkiv
• Polyakov, A.Y.; Kochkova, A.I.; Langørgen, Amanda; Vines, Lasse; Vasilev, A. & Shchemerov, I.V. [Vis alle 8 forfattere av denne artikkelen] (2023). On the possible nature of deep centers in Ga2O3. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. ISSN 0734-2101. 41(2), s. 023401-1–023401-6. doi: 10.1116/6.0002307. Fulltekst i vitenarkiv Vis sammendrag

  The electric field dependence of emission rate of the deep traps with level near Ec−0.6 eV, so-called E1 traps, was studied by means of deep level transient spectroscopy measurements over a wide range of applied voltages. The traps were initially introduced by 900 °C ampoule annealing in molecular hydrogen. The results indicate the activation energy of the centers and the ratio of high-field to low-field electron emission rates at a fixed temperature scale as the square root of electric field, suggesting that the centers behave as deep donors. The possible microscopic nature of the centers in view of recent theoretical calculations is discussed. The most likely candidates for the E1 centers are SiGa1–H or SnGa2–H complexes.

• Ghadi, Hemant; McGlone, Joe F.; Cornuelle, Evan; Senckowski, Alexander; Sharma, Shivam & Wong, Man Hoi [Vis alle 14 forfattere av denne artikkelen] (2023). Identification and characterization of deep nitrogen acceptors in beta-Ga2O3 using defect spectroscopies. APL Materials. ISSN 2166-532X. 11(11). doi: 10.1063/5.0160541. Fulltekst i vitenarkiv
• Mukhopadhyay, Partha; Hatipoglu, Isa; Frodason, Ymir Kalmann; Varley, Joel Basile; Williams, Martin S. & Hunter, Daniel A. [Vis alle 13 forfattere av denne artikkelen] (2022). Role of defects in ultra-high gain in fast planar tin gallium oxide UV-C photodetector by MBE. Applied Physics Letters. ISSN 0003-6951. 121(11). doi: 10.1063/5.0107557. Fulltekst i vitenarkiv
• Olsen, Vegard Skiftestad; Frodason, Ymir Kalmann; Hommedal, Ylva Knausgård; Nielsen, Dina Marie; Weiser, Philip Michael & Johansen, Klaus Magnus H [Vis alle 9 forfattere av denne artikkelen] (2022). Li and group-III impurity doping in ZnSnN2: Potential and limitations. PHYSICAL REVIEW MATERIALS. ISSN 2475-9953. 6(12), s. 1–8. doi: 10.1103/PhysRevMaterials.6.124602. Fulltekst i vitenarkiv
• Karsthof, Robert Michael; Frodason, Ymir Kalmann; Galeckas, Augustinas; Weiser, Philip Michael; Zviagin, Vitaly & Grundmann, Marius (2022). Light Absorption and Emission by Defects in Doped Nickel Oxide. Advanced Photonics Research. ISSN 2699-9293. 3(11). doi: 10.1002/adpr.202200138.
• Langørgen, Amanda; Zimmermann, Christian; Frodason, Ymir Kalmann; Verhoeven, Espen Førdestrøm; Weiser, Philip Michael & Karsthof, Robert Michael [Vis alle 8 forfattere av denne artikkelen] (2022). Influence of heat treatments in H2 and Ar on the E1 center in β-Ga2O3. Journal of Applied Physics. ISSN 0021-8979. 131(115702). doi: 10.1063/5.0083861. Fulltekst i vitenarkiv

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• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2023). Ge donor diffusion in β-Ga2O3.
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2023). Impurity diffusion in β-Ga2O3.
• Langørgen, Amanda; Frodason, Ymir Kalmann; Karsthof, Robert Michael; Wenckstern, Holger von; Thue Jensen, Ingvild & Vines, Lasse (2022). An electron trap in κ-Ga2O3 and the quest for its microscopic origin.
• Frodason, Ymir Kalmann; Varley, Joel Basile; Johansen, Klaus Magnus H; Vines, Lasse & Van de Walle, Chris G. (2022). Strongly anisotropic migration of the Ga vacancy in ß-Ga2O3.
• Frodason, Ymir Kalmann; Krzyzaniak, Patryk Piotr; Vines, Lasse; Varley, Joel Basile; Van de Walle, Chris G. & Johansen, Klaus Magnus H (2022). Ga vacancy-mediated diffusion of Sn donors in β-Ga2O3.
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2022). Diffusion of Zn in beta-Ga2O3.
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2022). Dynamic interaction of Zn and intrinsic defects in beta-Ga2O3.
• Vines, Lasse; Monakhov, Eduard & Kuznetsov, Andrej (2022). Defects in semiconductors. Journal of Applied Physics. ISSN 0021-8979. 132(15). doi: 10.1063/5.0127714. Fulltekst i vitenarkiv
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Vines, Lasse & Johansen, Klaus Magnus H (2022). Zn diffusion in 𝛽-Ga2O3 using SIMS.
• Krzyzaniak, Patryk Piotr; Frodason, Ymir Kalmann; Weiser, Philip Michael; Vines, Lasse & Johansen, Klaus Magnus H (2021). Diffusion of donor dopants in β-Ga2O3 and interplay with gallium vacancies.
• Frodason, Ymir Kalmann; Zimmermann, Christian; Verhoeven, Espen Førdestrøm; Weiser, Philip Michael; Vines, Lasse & Varley, Joel Basile (2021). Multistability of Ga-O divacancies in β-Ga2O3.
• Langørgen, Amanda; Karsthof, Robert Michael; Weiser, Philip Michael; Cavani, Olivier; Grasset, Romain & Frodason, Ymir Kalmann [Vis alle 8 forfattere av denne artikkelen] (2021). Steady-state Photocapacitance Spectroscopy of Intrinsic Defects in Electron-Irradiated β-Ga₂O₃.
• Zimmermann, Christian; Frodason, Ymir Kalmann; Varley, Joel Basile; Verhoeven, Espen Førdestrøm; Rønning, Vegard & Weiser, Philip Michael [Vis alle 15 forfattere av denne artikkelen] (2021). Identification of Fe-, Ti- and H-related Charge-state Transition Levels in β-Ga2O3.
• Krzyzaniak, Patryk Piotr; Vines, Lasse & Johansen, Klaus Magnus H (2021). Development of b-Ga2O3 as a novel material for power electronics, dopant diffusion and defect interaction. 7Letras.

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