rkarsthof

• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Galeckas, Augustinas; Kumar, Piyush; Kuznetsov, Andrej & Grossner, Ulrike [Vis alle 7 forfattere av denne artikkelen] (2024). Impact of carbon injection in 4H-SiC on defect formation and minority carrier lifetime. Materials Science in Semiconductor Processing. ISSN 1369-8001. 176. doi: 10.1016/j.mssp.2024.108316. 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.

• Ghezellou, Misagh; Kumar, Piyush; Bathen, Marianne E.; Karsthof, Robert Michael; Sveinbjörnsson, Einar Ö. & Grossner, Ulrike [Vis alle 9 forfattere av denne artikkelen] (2023). The role of boron related defects in limiting charge carrier lifetime in 4H-SiC epitaxial layers. APL Materials. ISSN 2166-532X. 11(3). doi: 10.1063/5.0142415. 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
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Grossner, Ulrike & Vines, Lasse (2022). Stability, Evolution and Diffusion of Intrinsic Point Defects in 4H-SiC. Materials Science Forum. ISSN 0255-5476. 1062, s. 371–375. doi: 10.4028/p-ryui6b. Fulltekst i vitenarkiv
• Galeckas, Augustinas; Karsthof, Robert Michael; Kingsly, Gana; Kok, Angela; Bathen, Marianne Etzelmüller & Vines, Lasse [Vis alle 7 forfattere av denne artikkelen] (2022). Cross-Sectional Carrier Lifetime Profiling and Deep Level Monitoring in Silicon Carbide Films Exhibiting Variable Carbon Vacancy Concentrations. Physica Status Solidi (a) applications and materials science. ISSN 1862-6300. s. 1–7. doi: 10.1002/pssa.202200449. 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
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Kuznetsov, Andrej & Vines, Lasse (2022). Formation of carbon interstitial-related defect levels by thermal injection of carbon into n-type 4H-SiC. Journal of Applied Physics. ISSN 0021-8979. 131. doi: 10.1063/5.0077308. Fulltekst i vitenarkiv
• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Karsthof, Robert Michael; Delteil, Aymeric; Sallet, Vincent & Kuznetsov, Andrej [Vis alle 7 forfattere av denne artikkelen] (2021). Resolving Jahn-Teller induced vibronic fine structure of silicon vacancy quantum emission in silicon carbide. Physical review B (PRB). ISSN 2469-9950. 104. doi: 10.1103/PhysRevB.104.045120. Fulltekst i vitenarkiv
• Karsthof, Robert Michael; von Wenckstern, Holger; Olsen, Vegard Skiftestad & Grundmann, Marius (2020). Identification of LiNi and VNi acceptor levels in doped nickel oxide. APL Materials. ISSN 2166-532X. 8(12). doi: 10.1063/5.0032102. Fulltekst i vitenarkiv
• Karsthof, Robert Michael; Anton, Arthur Markus; Kremer, Friedrich & Grundmann, Marius (2020). Nickel vacancy acceptor in nickel oxide: Doping beyond thermodynamic equilibrium. PHYSICAL REVIEW MATERIALS. ISSN 2475-9953. 4(3). doi: 10.1103/PhysRevMaterials.4.034601.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Vines, Lasse (2020). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC. Physical review B (PRB). ISSN 2469-9950. 102(18). doi: 10.1103/PhysRevB.102.184111. Fulltekst i vitenarkiv Vis sammendrag

  The development of defect populations after proton irradiation of n-type 4H-SiC and subsequent annealing experiments is studied by means of deep level transient (DLTS) and photoluminescence spectroscopy. A comprehensive model is suggested describing the evolution and interconversion of irradiation-induced point defects during annealing below 1000 ∘C. The model proposes the EH4 and EH5 traps frequently found by DLTS to originate from the (+/0) charge transition level belonging to different configurations of the carbon antisite-carbon vacancy (CAV) complex. Furthermore, we show that the transformation channel between the silicon vacancy (VSi) and CAV is effectively blocked under n-type conditions, but becomes available in samples where the Fermi level has moved towards the center of the band gap due to irradiation-induced donor compensation. The annealing of VSi and the carbon vacancy (VC) is shown to be dominated by recombination with residual self-interstitials at temperatures of up to 400 ∘C. Going to higher temperatures, a decay of the CAV pair density is reported which is closely correlated to a renewed increase of VC concentration. A conceivable explanation for this process is the dissociation of the CAV pair into separate carbon anitisites and VC defects. Lastly, the presented data supports the claim that the removal of free carriers in irradiated SiC is due to introduced compensating defects and not passivation of shallow nitrogen donors.

• Karsthof, Robert Michael; von Wenckstern, Holger; Zuniga-Perez, Jesus; Deparis, Christiane & Grundmann, Marius (2019). Nickel Oxide–Based Heterostructures with Large Band Offsets. Physica status solidi (b). ISSN 0370-1972. s. 1–11. doi: 10.1002/pssb.201900639. Fulltekst i vitenarkiv

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• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Kumar, Piyush; Galeckas, Augustinas; Kuznetsov, Andrej & Vines, Lasse [Vis alle 7 forfattere av denne artikkelen] (2022). Impact of C-injection in 4H-SiC on defect distribution and minority carrier lifetime.
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Kumar, Piyush; Galeckas, Augustinas; Kuznetsov, Andrej Yu. & Vines, Lasse [Vis alle 7 forfattere av denne artikkelen] (2022). Impact of C-injection in SiC on defect distribution and minority carrier lifetime.
• 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.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Vines, Lasse (2022). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• Galeckas, Augustinas; Karsthof, Robert Michael; Gana, Kingsly; Kok, Angela; Bathen, Marianne Etzelmüller & Vines, Lasse [Vis alle 7 forfattere av denne artikkelen] (2022). Cross-sectional carrier lifetime profiling and deep level monitoring in silicon carbide films exhibiting variable carbon vacancy concentrations. Vis sammendrag

  We report on the carrier lifetime control over 150 μmthick 4H-SiC epitaxial layers via thermal generation and annihilation of carbon vacancy (VC) related Z1/2lifetime killer sites. The defect developments upon typical SiC processing steps, such as high- and moderate-temperature anneals in the presence of a carbon cap,are monitored by combining electrical characterization techniques capable of VC depth-profiling, capacitance-voltage (CV) and deep-level transient spectroscopy (DLTS), with a novel all-optical approach of cross-sectional carrier lifetime profiling across 4H-SiC epilayer/substrate based on imaging time-resolved photoluminescence (TRPL) spectroscopy in orthogonal pump-probe geometry,which readily exposes in-depth efficacy ofdefect reduction and surface recombination effects.The lifetime control is realized byinitialhigh-temperature treatment (1800ºC) to increase VC concentration to ~1013 cm-3 level followed by a moderate-temperature (1500ºC) post-annealing of variable duration under C-rich thermodynamic equilibrium conditions. The post-annealing carried out for 5 hours in effect eliminates VCthroughout the entire ultra-thick epilayer. The reduction of VC-related Z1/2 sites is proven by a significant lifetime increase from 0.8 μs to 2.5 μs. We discuss the upper limit of lifetimes in terms of carrier surface leakage and presence of other non-radiative recombination centers besides Z1/2, possibly related to residual impurities such as boron.

• Norby, Truls; Karsthof, Robert Michael; Saeed, Sarmad Waheed; Kuznetsov, Andrej & Vines, Lasse (2022). The p-n junction has nothing to do with ionics. Does it? .
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Linnarsson, Margareta; Galeckas, Augustinas; Kuznetsov, Andrej & Grossner, Ulrike [Vis alle 7 forfattere av denne artikkelen] (2021). Stability, evolution and diffusion of intrinsic point defects in 4H-SiC.
• Karsthof, Robert Michael; von Wenckstern, Holger; Olsen, Vegard Skiftestad & Grundmann, Marius (2021). Identification of LiNi and VNi acceptor levels in doped nickel oxide.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Vines, Lasse (2021). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Enga, Marius & Vines, Lasse (2021). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• 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.
• 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.
• Tømta, Sindre Ludvigsen; Kuznetsov, Andrej; Gongora, David Rivas & Karsthof, Robert Michael (2021). Single-Photon Emitters in Silicon for Quantum Technology. Universitetet i Oslo.

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