Marianne Etzelmüller Bathen

• Ousdal, Erlend Lemva; Bathen, Marianne Etzelmüller; Medeiros, Helton Goncalves de; Galeckas, Augustinas; Kumar, Piyush & Martins, Maria I.M. [Show all 10 contributors for this article] (2026). Control and tuning of color centers in 4H silicon carbide by application of electric field via Schottky diode. Materials Science in Semiconductor Processing. ISSN 1369-8001. 201. doi: 10.1016/j.mssp.2025.110097. Full text in Research Archive Show summary

  The ability to tune and manipulate the energy and intensity of photons emitted from color centers in semiconductors is of great importance for developing point defect quantum emitters as a platform for future quantum technology (QT) applications. One of the promising materials to realize point defect based QT is silicon carbide (SiC), as it combines a plethora of color center candidates with mature material processing and device fabrication. Here we explore the use of a Schottky diode, fabricated on a highly doped n-type 4H-SiC epitaxial layer, to control and modulate defect-related emission under both forward and reverse bias conditions. Zero phonon lines (ZPLs) from three prominent color centers are investigated: V1, V1’ and V2 assigned to the silicon vacancy, B1 and B2 from the carbon antisite-vacancy pair, and PL4 of the divacancy complex. All the studied defect-related emission wavelengths are found to shift in response to applied bias, but with a varying magnitude and direction of the shift. The electric field-induced variations are assigned to Stark effect and current flow within the device. Furthermore, two unknown defect signatures, labeled K1 and K2, are observed in the vicinity (within 2 meV) of the V2 ZPL and exhibit a strong forward bias dependence. A possible origin related to silicon vacancies perturbed by nearby carbon antisites is discussed.

• Ousdal, Erlend Lemva; Ghezellou, Misagh; Ul-Hassan, Jawad; Kuznetsov, Andrej; Vines, Lasse & Bathen, Marianne Etzelmüller (2025). Identification of electrically active defects in 6⁢𝐻-SiC. PHYSICAL REVIEW MATERIALS. 9(12). doi: 10.1103/qzfw-162p. Full text in Research Archive Show summary

  Deep level defects in silicon carbide (SiC) are of great importance for developing both power electronics and quantum technology applications based on SiC material. While the more technologically mature 4⁢𝐻 polytype has been widely explored, electrical identification of deep level defect states in 6⁢𝐻 -SiC has not been completed. This work aims to identify irradiation-induced charge state transition levels arising from intrinsic defects in 6⁢𝐻 -SiC using deep level transient spectroscopy (DLTS) and the formation energy diagram formalism based on density functional theory (DFT) calculations. By comparing experimental results of 6⁢𝐻 -SiC epitaxial layers with measurements of 4⁢𝐻 -SiC material that has been grown under identical conditions, combined with DFT calculations, we assign possible origins for the observed DLTS-signatures.

• Silkinis, Rokas; Maciaszek, Marek; Žalandauskas, Vytautas; Bathen, Marianne Etzelmüller; Vines, Lasse & Alkauskas, Audrius [Show all 7 contributors for this article] (2025). Optical lineshapes of the C center in silicon from ab initio calculations: Interplay of localized modes and bulk phonons. Physical review B (PRB). ISSN 2469-9950. 111(12). doi: 10.1103/PhysRevB.111.125136. Full text in Research Archive
• Ghezellou, Misagh; Ousdal, Erlend Lemva; Bathen, Marianne Etzelmüller; Vines, Lasse & Ul-Hassan, Jawad (2025). Influence of different hydrocarbons on impurities and minority carrier lifetime in 4H-SiC epitaxial layers. JPhys Materials. 8, p. 1–12. doi: 10.1088/2515-7639/adb7c0. Full text in Research Archive Show summary

  This study explores the influence of different hydrocarbons, methane and propane, on the properties of 4H-SiC epitaxial layers grown by chloride-based chemical vapor deposition. By systematically varying the C/Si and N/C ratios during epitaxial growth, and employing a comprehensive suite of characterization techniques, a better understanding of how growth conditions influence material properties is gained. We show that the n-type dopant incorporation strongly depends on the choice of hydrocarbon especially at lower doping levels. Furthermore, we have observed that methane contributes to a relatively longer carrier lifetime value compared to propane, though a similar lifetime limiting carbon vacancy defect concentration has been observed for both hydrocarbons in as-grown epitaxial layers. Moreover, additional defect levels are also suggested by deep-level transient spectroscopy, potentially related to chlorine complexes, with varying concentrations depending on the choice of hydrocarbon and C/Si ratio. These observations offer insights into the complicated interplay of factors influencing doping, minority carrier lifetime, and defect formation in 4H-SiC epitaxial layers during the epitaxial growth process, and contribute to the optimization of growth parameters depending on the application in question.

• Martinella, Corinna; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Grossner, Ulrike (2025). Formation of extended defects in heavy-ion-degraded SiC power MOSFETs. APL Materials. 13(5). doi: 10.1063/5.0258995. Full text in Research Archive Show summary

  Silicon carbide (SiC) power devices offer distinct advantages over silicon-based technology and are envisioned to be of great benefit also for space applications. However, their reliability in space is reduced due to the high susceptibility to space-radiation, where single event effects (SEEs) induced by heavy ions are a particular risk. This work focuses on identifying the microscopic origin of a specific non-destructive SEE in SiC power MOSFETs known as single event leakage current (SELC), characterized by a permanent degradation of the gate and drain leakage currents and observed at a relatively low blocking voltage during heavy-ion exposure. The effect investigated is categorized as SELC II, and devices exposed to both broad-beam and microbeam of heavy-ions are studied herein. Using imaging photoluminescence spectroscopy, we observe distinct bright-spots after heavy-ion irradiation, containing spectral features that indicate the formation of stacking faults during exposure and subsequent biasing.

• Hommedal, Ylva Knausgård; Bathen, Marianne Etzelmüller; Reinertsen, Vilde Mari; Johansen, Klaus Magnus H; Vines, Lasse & Frodason, Ymir Kalmann (2024). Theoretical modeling of defect diffusion in wide bandgap semiconductors. Journal of Applied Physics. ISSN 0021-8979. 135. doi: 10.1063/5.0205866. Full text in Research Archive Show summary

  Since the 1940s, it has been known that diffusion in crystalline solids occurs due to lattice defects. The diffusion of defects can have a great impact on the processing and heat treatment of materials as the microstructural changes caused by diffusion can influence the material qualities and properties. It is, therefore, vital to be able to control the diffusion. This implies that we need a deep understanding of the interactions between impurities, matrix atoms, and intrinsic defects. The role of density functional theory (DFT) calculations in solid-state diffusion studies has become considerable. The main parameters to obtain in defect diffusion studies with DFT are formation energies, binding energies, and migration barriers. In particular, the utilization of the nudged elastic band and the dimer methods has improved the accuracy of these parameters. In systematic diffusion studies, the combination of experimentally obtained results and theoretical predictions can reveal information about the atomic diffusion processes. The combination of the theoretical predictions and the experimental results gives a unique opportunity to compare parameters found from the different methods and gain knowledge about atomic migration. In this Perspective paper, we present case studies on defect diffusion in wide bandgap semiconductors. The case studies cover examples from the three diffusion models: free diffusion, trap-limited diffusion, and reaction diffusion. We focus on the role of DFT in these studies combined with results obtained with the experimental techniques secondary ion mass spectrometry and deep-level transient spectroscopy combined with diffusion simulations.

• Bathen, Marianne Etzelmüller; Kumar, Piyush; Ghezellou, Misagh; Belanche, Manuel; Vines, Lasse & Ul-Hassan, Jawad [Show all 7 contributors for this article] (2024). Dual configuration of shallow acceptor levels in 4H-SiC. Materials Science in Semiconductor Processing. ISSN 1369-8001. 177. doi: 10.1016/j.mssp.2024.108360. Full text in Research Archive Show summary

  Acceptor dopants in 4H-SiC exhibit energy levels that are located deeper in the band gap than the thermal energy at room temperature (RT), resulting in incomplete ionization at RT. Therefore, a comprehensive understanding of the defect energetics and how the impurities are introduced into the material is imperative. Herein, we study impurity related defect levels in 4H-SiC epitaxial layers (epi-layers) grown by chemical vapor deposition (CVD) under various conditions using minority carrier transient spectroscopy (MCTS). We find two trap levels assigned to boron impurities, B and D, which are introduced to varying degrees depending on the growth conditions. A second acceptor level that was labeled X in the literature and attributed to impurity related defects is also observed. Importantly, both the B and X levels exhibit fine structure revealed by MCTS measurements. We attribute the fine structure to acceptor impurities at hexagonal and pseudo-cubic lattice sites in 4H-SiC, and tentatively assign the X peak to Al based on experimental findings and density functional theory calculations.

• Ousdal, Erlend Lemva; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Kuznetsov, Andrej & Vines, Lasse (2024). Formation and stability of point defect color centers in 6H silicon carbide. Journal of Applied Physics. ISSN 0021-8979. 135(22). doi: 10.1063/5.0205832. Full text in Research Archive Show summary

  Point defect color centers acting as single-photon emitters are promising for quantum technology applications and have been extensively studied, e.g., in the 4H polytype of silicon carbide (SiC). However, the physics of such color centers in other SiC polytypes is much less explored. Herein, we study the formation and thermal stability of such color centers in 6H-SiC using photoluminescence spectroscopy. The emissions from typical single-photon emitters, such as silicon vacancies, divacancies, and carbon antisite-vacancy pairs in 6H-SiC, were monitored as a function of the proton irradiation fluence and post-irradiation annealing, and compared to that in 4H-SiC. Overall, at the background of similarities between the emission behavior in 4H- and 6H-SiC polytypes, we observed prominent differences; e.g., for the thermal stability of the carbon antisite-vacancy pair, which exhibited maximized emissions upon 300 and 900  *C anneals in 4H- and 6H-SiC, respectively. Moreover, we observed a range of defect emission signatures not previously reported for 6H-SiC in the literature and discussed their potential origin in the context of the thermal stability. For example, among the PL-lines in 6H-SiC, we detected periodically repeatable emission signatures, resembling the so-called L-lines recently reported in 4H-SiC, even though their exact origin has not yet been settled in the literature. Thus, we use color centers comparison in different polytypes to better understand the nature of the single-photon emitters in SiC.

• Kumar, Piyush; Medeiros, Helton G. de; Race, Salvatore; Martins, Maria I. M.; Ammann, Pascal & Bathen, Marianne Etzelmüller [Show all 8 contributors for this article] (2024). Exploring the border traps near the valence band in the Si⁢O2-Si⁢C system using above-band-gap optical excitation. Physical Review Applied. 21. doi: 10.1103/PhysRevApplied.21.064065. Full text in Research Archive
• Kumar, Piyush; Krummenacher, Mira; Medeiros, Helton G. de; Race, Salvatore; Natzke, Philipp & Kovacevic-Badstübner, Ivana [Show all 8 contributors for this article] (2024). Exploring the border traps near the SiO2-SiC interface using conductance measurements. 2024 IEEE International Reliability Physics Symposium (IRPS). ISSN 1938-1891. p. 1–6. doi: 10.1109/IRPS48228.2024.10529387. Full text in Research Archive
• Kumar, Piyush; Bathen, Marianne Etzelmüller; Martins, Maria I. M.; Prokscha, Thomas & Grossner, Ulrike (2024). Electrically active defects induced by thermal oxidation and post-oxidation annealing of n-type 4H-SiC. Journal of Applied Physics. ISSN 0021-8979. 135(18). doi: 10.1063/5.0205965. Full text in Research Archive
• Kumar, Piyush; Martins, Maria I. M.; Bathen, Marianne Etzelmüller; Prokscha, Thomas & Grossner, Ulrike (2024). Al-implantation induced damage in 4H-SiC. Materials Science in Semiconductor Processing. ISSN 1369-8001. 174. doi: 10.1016/j.mssp.2024.108241. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Galeckas, Augustinas; Kumar, Piyush; Kuznetsov, Andrej & Grossner, Ulrike [Show all 7 contributors for this article] (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. Full text in Research Archive
• Jousseaume, Yann; Kumar, Piyush; Bathen, Marianne Etzelmüller; Cauwet, François; Grossner, Ulrike & Ferro, Gabriel (2024). Surface Structuring of Patterned 4H-SiC Surfaces Using a SiC/Si/SiC Sandwich Approach. Materials Science Forum. ISSN 0255-5476. p. 7–12. doi: 10.4028/p-auZ0OI. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Selnesaunet, Gard Momrak; Enga, Marius; Kjeldby, Snorre Braathen; Müting, Johanna & Vines, Lasse [Show all 7 contributors for this article] (2023). Charge State Control Over Point Defects in SiC Devices. Defect and Diffusion Forum. ISSN 1012-0386. 425, p. 35–42. doi: 10.4028/p-6ho92o. Full text in Research Archive Show summary

  Point defects in silicon carbide (SiC) are well positioned for integration with SiC based quantum photonic devices due to the maturity of SiC material and fabrication technology, the plethora of candidate quantum emitters that can be formed in SiC, and the potential for emission over a wide spectral range from the visible to the infrared. However, for each of the available color centers in SiC, only one of the charge states has displayed quantum emission, meaning that the emission strongly depends on the Fermi level and hence the doping concentration in the material. In this contribution, we discuss the methodology and mechanism for electrical charge-state control over point defects in SiC devices.

• Dorfer, Christian; Bathen, Marianne Etzelmüller; Race, Salvatore; Kumar, Piyush; Tsibizov, Alexander & Woerle, Judith [Show all 7 contributors for this article] (2023). Mapping the impact of defect distributions in silicon carbide devices using the edge transient-current technique. Applied Physics Letters. ISSN 0003-6951. 122. doi: 10.1063/5.0142217. Full text in Research Archive
• Kumar, Piyush; Martins, Maria M.; Bathen, Marianne Etzelmüller; Woerle, Judith; Prokscha, Thomas & Grossner, Ulrike (2023). Investigation of the SiO2-SiC Interface Using Low-Energy Muon-Spin-Rotation Spectroscopy. Physical Review Applied. 19. doi: 10.1103/PhysRevApplied.19.054025. Full text in Research Archive
• Belanche, Manuel; Bathen, Marianne Etzelmüller; Kumar, Piyush; Dorfer, Christian; Martinella, Corinna & Grossner, Ulrike (2023). Minority Carrier Traps Induced by Neutron Reactions with 4H-SiC. Defect and Diffusion Forum. ISSN 1012-0386. 426, p. 23–28. doi: 10.4028/p-724d7y. Full text in Research Archive
• Martinella, Corinna; Bathen, Marianne Etzelmüller; Javanainen, Arto & Grossner, Ulrike (2023). Heavy-Ion-Induced Defects in Degraded SiC Power MOSFETs. Materials Science Forum. ISSN 0255-5476. 1090, p. 179–184. doi: 10.4028/p-3y3lv4. Full text in Research Archive
• Für, Natalija; Belanche, Manuel; Martinella, Corinna; Kumar, Piyush; Bathen, Marianne Etzelmüller & Grossner, Ulrike (2023). Investigation of Electrically Active Defects in SiC Power Diodes Caused by Heavy Ion Irradiation. IEEE Transactions on Nuclear Science. ISSN 0018-9499. 70(8), p. 1892–1899. doi: 10.1109/TNS.2023.3242760. Full text in Research Archive
• Race, Salvatore; Kumar, Piyush; Natzke, Philipp; Kovacevic-Badstuebner, Ivana; Bathen, Marianne Etzelmüller & Romano, Gianpaolo [Show all 12 contributors for this article] (2023). Gate Impedance Analysis of SiC power MOSFETs with SiO2 and High-k Dielectric. Proceedings of the International Symposium on Power Semiconductor Devices & ICs. ISSN 1063-6854. p. 9–12. doi: 10.1109/ISPSD57135.2023.10147725. Full text in Research Archive
• Kumar, Piyush; Belanche, Manuel; Für, Natalija; Guzenko, Luka; Woerle, Judith & Bathen, Marianne Etzelmüller [Show all 7 contributors for this article] (2023). Energy-Dependent Impact of Proton Irradiation on 4H-SiC Schottky Diodes. Materials Science Forum. ISSN 0255-5476. 1092, p. 187–192. doi: 10.4028/p-0y444y. Full text in Research Archive
• Kumar, Piyush; Martins, Maria M.; Bathen, Marianne Etzelmüller; Woerle, Judith; Prokscha, Thomas & Grossner, Ulrike (2022). Depth-Resolved Study of the SiO2- SiC Interface Using Low-Energy Muon Spin Rotation Spectroscopy. Materials Science Forum. ISSN 0255-5476. 1062, p. 315–319. doi: 10.4028/p-w73601. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Lew, C. T.-K.; Woerle, Judith; Dorfer, Christian; Grossner, Ulrike & Castelletto, Stefania [Show all 7 contributors for this article] (2022). Characterization methods for defects and devices in silicon carbide. Journal of Applied Physics. ISSN 0021-8979. 131(14). doi: 10.1063/5.0077299. Full text in Research Archive
• Galeckas, Augustinas; Karsthof, Robert Michael; Kingsly, Gana; Kok, Angela; Bathen, Marianne Etzelmüller & Vines, Lasse [Show all 7 contributors for this article] (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. p. 1–7. doi: 10.1002/pssa.202200449. Full text in Research Archive Show summary

  The carrier lifetime control over 150 μm thick 4H-SiC epitaxial layers via thermal generation and annihilation of carbon vacancy (VC) related Z1/2 lifetime killer sites is reported. 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 of defect reduction and surface recombination effects. The lifetime control is realized by initial high-temperature treatment (1800 °C) to increase VC concentration to ≈1013 cm−3 level followed by a moderate-temperature (1500 °C) post-annealing of variable duration under C-rich thermodynamic equilibrium conditions. The post-annealing carried out for 5 h in effect eliminates VC throughout the entire ultra-thick epilayer. The reduction of VC-related Z1/2 sites is proven by a significant lifetime increase from 0.8 to 2.5 μs. The upper limit of lifetimes in terms of carrier surface leakage and the presence of other nonradiative recombination centers besides Z1/2, possibly related to residual impurities such as boron are discussed.

• Reed, B.P.; Bathen, Marianne Etzelmüller; Ash, J.W.R.; Meara, C.J.; Zakharov, A.A. & Goss, J.P. [Show all 9 contributors for this article] (2022). Diamond (111) surface reconstruction and epitaxial graphene interface. Physical review B (PRB). ISSN 2469-9950. 105(20). doi: 10.1103/PhysRevB.105.205304. Full text in Research Archive
• Hebnes, Oliver Lerstøl; Bathen, Marianne Etzelmüller; Schøyen, Øyvind Sigmundson; Winther-Larsen, Sebastian Gregorius; Vines, Lasse & Hjorth-Jensen, Morten (2022). Predicting solid state material platforms for quantum technologies. npj Computational Materials. 8(1). doi: 10.1038/s41524-022-00888-3. Full text in Research Archive Show summary

  Abstract Semiconductor materials provide a compelling platform for quantum technologies (QT). However, identifying promising material hosts among the plethora of candidates is a major challenge. Therefore, we have developed a framework for the automated discovery of semiconductor platforms for QT using material informatics and machine learning methods. Different approaches were implemented to label data for training the supervised machine learning (ML) algorithms logistic regression, decision trees, random forests and gradient boosting. We find that an empirical approach relying exclusively on findings from the literature yields a clear separation between predicted suitable and unsuitable candidates. In contrast to expectations from the literature focusing on band gap and ionic character as important properties for QT compatibility, the ML methods highlight features related to symmetry and crystal structure, including bond length, orientation and radial distribution, as influential when predicting a material as suitable for QT.

• 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, p. 371–375. doi: 10.4028/p-ryui6b. Full text in Research Archive Show summary

  Silicon carbide (SiC) is a wide band-gap semiconductor of great technological importance, showing promise for application areas ranging from quantum computing and communication to power devices. Vital in both the contexts of power devices and quantum technology is the understanding of intrinsic defects that are introduced during various device processing steps, both immediately after their formation and over the course of defect evolution with temperature. Here we monitor the formation and evolution of intrinsic point defects in n-type 4H-SiC after proton irradiation at room temperature and subsequent annealing in the temperature range 300-1000 °C, and discuss the nature and origin of the EH 4 and EH 5 deep level defects observed by deep level transient spectroscopy around 400-500 K. In particular, the controversy on the nature of the EH5 trap in particular is addressed, where we propose the presence of two overlapping defect peaks: one metastable level that appears after low energy electron irradiation below the silicon displacement limit, and one more stable level that gradually decreases in concentration until an annealing temperature of 1000°C. We argue that the former is likely related to carbon interstitials, while the latter was recently tentatively attributed to the carbon antisite-vacancy pair.

• 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. Full text in Research Archive Show summary

  Electrical properties of point defects in 4𝐻-SiC have been studied extensively, but those related to carbon interstitials (Ci) have remained elusive until now. Indeed, when introduced via ion irradiation or implantation, signatures related to Ci observed by deep level transient spectroscopy tend to overlap with those of other primary defects, making the direct identification of Ci-related levels difficult. Recent literature has suggested to assign the so-called M center, often found in as-irradiated 4𝐻-SiC, to charge state transitions of the Ci defect in different configurations. In this work, we have introduced excess carbon into low-doped 𝑛-type 150 𝜇m thick 4𝐻-SiC epilayers by thermal annealing, with a pyrolyzed carbon cap on the sample surface acting as a carbon source. Because the layers exhibited initially low concentrations of carbon vacancies ([𝑉C]=1011cm), this enabled us to study the case of complete VC annihilation and formation of defects due to excess carbon, i.e., carbon interstitials Ci and their higher-order complexes. We report on the occurrence of several new levels upon C injection, which are likely Ci-related. Their properties are different from those found for the M center, which point toward a different microscopic identity of the detected levels. This suggests the existence of a rich variety of Ci-related defects. The study will also help generating new insights into the microscopic process of VC annihilation during carbon injection processes.

• Bathen, Marianne Etzelmüller & Vines, Lasse (2021). Manipulating Single-Photon Emission from Point Defects in Diamond and Silicon Carbide. Advanced Quantum Technologies. 4. doi: 10.1002/qute.202100003. Full text in Research Archive Show summary

  Point defects in semiconductors are emerging as an important contender platform for quantum technology (QT) applications, showing potential for quantum computing, communication, and sensing. Indeed, point defects have been employed as nuclear spins for nanoscale sensing and memory in quantum registers, localized electron spins for quantum bits, and emitters of single photons in quantum communication and cryptography. However, to utilize point defects in semiconductors as single-photon sources for QT, control over the influence of the surrounding environment on the emission process must be first established. Recent works have revealed strong manipulation of emission energies and intensities via coupling of point defect wavefunctions to external factors such as electric fields, strain and photonic devices. This review presents the state-of-the-art on manipulation, tuning, and control of single-photon emission from point defects focusing on two leading semiconductor materials—diamond and silicon carbide.

• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Karsthof, Robert Michael; Delteil, Aymeric; Sallet, Vincent & Kuznetsov, Andrej [Show all 7 contributors for this article] (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. Full text in Research Archive Show summary

  Point defects in semiconductors are promising single-photon emitters (SPEs) for quantum computing, communication, and sensing applications. However, factors such as emission brightness, purity. and indistinguishability are limited by interactions between localized defect states and the surrounding environment. Therefore, it is important to map the full emission spectrum from each SPE, to understand the complex interplay between the different defect configurations, their surroundings, and external perturbations. Herein, we investigate a family of regularly spaced sharp luminescence peaks appearing in the near-infrared portion of photoluminescence (PL) spectra from n-type 4H-SiC samples after irradiation. This periodic emitter family, labeled the L lines, is only observed when the zero-phonon line signatures of the negatively charged Si vacancy (so-called V lines) are present. The L lines appear with 1.45meV and 1.59meV energy spacing after H and He irradiation and increase linearly in intensity with fluence—reminiscent of the intrinsic defect trend. Furthermore, we monitor the dependence of the L-line emission energy and intensity on heat treatments, electric field strength, and PL collection temperature, discussing these data in the context of the L lines. Based on the strong similarity between the irradiation, electric field, and thermal responses of the L and V lines, the L lines are attributed to the Si vacancy in 4H-SiC. The regular and periodic appearance of the L lines provides strong arguments for a vibronic origin explaining the oscillatory multipeak spectrum. To account for the small energy separation of the L lines, we propose a model based on rotations of distortion surrounding the Si vacancy driven by a dynamic Jahn-Teller effect.

• Bathen, Marianne Etzelmüller; Linnarsson, Margareta; Ghezellou, Mizagh; Hassan, Jawad Ul & Vines, Lasse (2020). Influence of Carbon Cap on Self-Diffusion in Silicon Carbide. Crystals. 10(9). doi: 10.3390/cryst10090752. Full text in Research Archive Show summary

  Self-diffusion of carbon (12C and 13C) and silicon (28Si and 30Si) in 4H silicon carbide has been investigated by utilizing a structure containing an isotope purified 4H-28Si12C epitaxial layer grown on an n-type (0001) 4H-SiC substrate, and finally covered by a carbon capping layer (C-cap). The 13C and 30Si isotope profiles were monitored using secondary ion mass spectrometry (SIMS) following successive heat treatments performed at 2300−−2450∘C in Ar atmosphere using an inductively heated furnace. The 30Si profiles show little redistribution within the studied temperature range, with the extracted diffusion lengths for Si being within the error bar for surface roughening during annealing, as determined by profilometer measurements. On the other hand, a significant diffusion of 13C was observed into the isotope purified layer from both the substrate and the C-cap. A diffusivity of D=8.3×106e−10.4/kBT cm2/s for 13C was extracted, in contrast to previous findings that yielded lower both pre-factors and activation energies for C self-diffusion in SiC. The discrepancy between the present measurements and previous theoretical and experimental works is ascribed to the presence of the C-cap, which is responsible for continuous injection of C interstitials during annealing, and thereby suppressing the vacancy mediated diffusion.

• Reinertsen, Vilde Mari; Weiser, Philip Michael; Frodason, Ymir Kalmann; Bathen, Marianne Etzelmüller; Vines, Lasse & Johansen, Klaus Magnus H (2020). Anisotropic and trap-limited diffusion of hydrogen/deuterium in monoclinic gallium oxide single crystals. Applied Physics Letters. ISSN 0003-6951. 117. doi: 10.1063/5.0027333. Full text in Research Archive Show summary

  The effect of lattice anisotropy on the diffusion of hydrogen (H)/deuterium (2H) in b-Ga2O3 was investigated using secondary ion mass spectrometry (SIMS) and hybrid-functional calculations. Concentration-depth profiles of 2H-implanted single crystals show that 2H can diffuse along the direction perpendicular to the (010) surface at temperatures as low as 300 degC, whereas diffusion along the direction perpendicular to the (-201) surface occurs only around 500 degC. For both directions, the evolution of the 2H concentration–depth profiles after heat treatments can be modeled by trap-limited diffusion. Moreover, the traps can be present in the as-received crystals or created during ion implantation. Comparison of the experimentally obtained binding energy for 2H to the trap (2.3+/-0.2 eV) with the binding energies determined from first-principles calculations suggests that intrinsic point defects (e.g., VGa^ib) or defect complexes (e.g., VGa(2)VO(2)) are excellent candidates for the trap and will play a crucial role in the diffusion of H or 2H in b-Ga2O3.

• Woerle, Judith; Bathen, Marianne Etzelmüller; Prokscha, Thomas; Galeckas, Augustinas; Ayedh, Hussein Mohammed Hussein & Vines, Lasse [Show all 7 contributors for this article] (2020). Muon Interaction with Negative-U and High-Spin-State Defects: Differentiating Between C and Si Vacancies in 4H-SiC. Physical Review Applied. 14. doi: 10.1103/PhysRevApplied.14.054053. Full text in Research Archive Show summary

  Low-energy muon-spin-rotation spectroscopy (LE-μSR) is employed to study silicon and carbon vacancies in proton-irradiated 4H-SiC. We show that the implanted muon is quickly attracted to the negative Si vacancy (VSi), where it forms a paramagnetic muonium (Mu0) state, resulting in a reduction of the diamagnetic fraction. In samples with predominantly C vacancies (VC), on the other hand, the formation of Mu0 is very short lived and the muon quickly captures a second electron to form a diamagnetic Mu− state. The results are corroborated by density-functional calculations, where significant differences in the relaxation mechanism of the nearest-neighbor dangling bonds of the vacancies are discussed. We propose that the LE-μSR technique is capable of differentiating between high-spin and negative-U behavior in semiconducting materials. Finally, our findings emphasize the large potential of LE-μSR to probe near-surface semiconductor defects, a capability that is crucial for further development of many electronic and quantum technology applications.

• 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. Full text in Research Archive Show summary

  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.

• Bathen, Marianne Etzelmüller; Vines, Lasse & Coutinho, José (2020). First-principles calculations of Stark shifts of electronic transitions for defects in semiconductors: the Si vacancy in 4H-SiC. Journal of Physics: Condensed Matter. ISSN 0953-8984. 33(7). doi: 10.1088/1361-648X/abc804. Full text in Research Archive Show summary

  Point defects in solids are promising single-photon sources with application in quantum sensing, computing and communication. Herein, we describe a theoretical framework for studying electric field effects on defect-related electronic transitions, based on density functional theory calculations with periodic boundary conditions. Sawtooth-shaped electric fields are applied perpendicular to the surface of a two-dimensional defective slab, with induced charge singularities being placed in the vacuum layer. The silicon vacancy (VSi) in 4H-SiC is employed as a benchmark system, having three zero-phonon lines in the near-infrared (V1, V1' and V2) and exhibiting Stark tunability via fabrication of Schottky barrier or p-i-n diodes. In agreement with experimental observations, we find an approximately linear field response for the zero-phonon transitions of VSi involving the decay from the first excited state (named V1 and V2). However, the magnitude of the Stark shifts are overestimated by nearly a factor of 10 when comparing to experimental findings. We discuss several theoretical and experimental aspects which could affect the agreement.

• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Coutinho, José & Vines, Lasse (2020). Influence of hydrogen implantation on emission from the silicon vacancy in 4H-SiC. Journal of Applied Physics. ISSN 0021-8979. 127(8). doi: 10.1063/1.5140659. Full text in Research Archive Show summary

  The silicon vacancy (VSi) in 4H-SiC is a room temperature single-photon emitter with a controllable high-spin ground state and is a promising candidate for future quantum technologies. However, controlled defect formation remains a challenge, and, recently, it was shown that common formation methods such as proton irradiation may, in fact, lower the intensity of photoluminescence (PL) emission from VSi as compared to other ion species. Herein, we combine hybrid density functional calculations and PL studies of the proton-irradiated n-type 4H-SiC material to explore the energetics and stability of hydrogen-related defects, situated both interstitially and in defect complexes with VSi, and confirm the stability of hydrogen in different interstitial and substitutional configurations. Indeed, VSi-H is energetically favorable if VSi is already present in the material, e.g., following irradiation or ion implantation. We demonstrate that hydrogen has a significant impact on electrical and optical properties of VSi, by altering the charge states suitable for quantum technology applications, and provide an estimate for the shift in thermodynamic transition levels. Furthermore, by correlating the theoretical predictions with PL measurements of 4H-SiC samples irradiated by protons at high (400 C) and room temperatures, we associate the observed quenching of VSi emission in the case of high-temperature and high-fluence proton irradiation with the increased mobility of Hi, which may initiate VSi-H complex formation at temperatures above 400 C. The important implication of hydrogen being present is that it obstructs the formation of reliable and efficient single-photon emitters based on silicon vacancy defects in 4H-SiC.

• Vasquez, Geraldo Cristian; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Bazioti, Kalliopi; Johansen, Klaus Magnus H & Maestre, D. [Show all 11 contributors for this article] (2020). Strain Modulation of Si Vacancy Emission from SiC Micro- and Nanoparticles. Nano Letters. ISSN 1530-6984. 20(12), p. 8689–8695. doi: 10.1021/acs.nanolett.0c03472. Full text in Research Archive Show summary

  Single-photon emitting point defects in semiconductors have emerged as strong candidates for future quantum technology devices. In the present work, we exploit crystalline particles to investigate relevant defect localizations, emission shifting, and waveguiding. Specifically, emission from 6H-SiC micro- and nanoparticles ranging from 100 nm to 5 μm in size is collected using cathodoluminescence (CL), and we monitor signals attributed to the Si vacancy (VSi) as a function of its location. Clear shifts in the emission wavelength are found for emitters localized in the particle center and at the edges. By comparing spatial CL maps with strain analysis carried out in transmission electron microscopy, we attribute the emission shifts to compressive strain of 2–3% along the particle a-direction. Thus, embedding VSi qubit defects within SiC nanoparticles offers an interesting and versatile opportunity to tune single-photon emission energies while simultaneously ensuring ease of addressability via a self-assembled SiC nanoparticle matrix.

• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Müting, Johanna; Ayedh, Hussein Mohammed Hussein; Grossner, Ulrike & Coutinho, José [Show all 8 contributors for this article] (2019). Electrical charge state identification and control for the silicon vacancy in 4H-SiC. npj Quantum Information. 5(1), p. 1–9. doi: 10.1038/s41534-019-0227-y. Full text in Research Archive Show summary

  Reliable single-photon emission is crucial for realizing efficient spin-photon entanglement and scalable quantum information systems. The silicon vacancy (VSi) in 4H-SiC is a promising single-photon emitter exhibiting millisecond spin coherence times, but suffers from low photon counts, and only one charge state retains the desired spin and optical properties. Here, we demonstrate that emission from VSi defect ensembles can be enhanced by an order of magnitude via fabrication of Schottky barrier diodes, and sequentially modulated by almost 50% via application of external bias. Furthermore, we identify charge state transitions of VSi by correlating optical and electrical measurements, and realize selective population of the bright state. Finally, we reveal a pronounced Stark shift of 55 GHz for the V1′ emission line state of VSi at larger electric fields, providing a means to modify the single-photon emission. The approach presented herein paves the way towards obtaining complete control of, and drastically enhanced emission from, VSi defect ensembles in 4H-SiC highly suitable for quantum applications.

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• Frøland, Mariann Carlsen; Furlan, Riccardo; Bygdås, Martin; Olsen, Vegard Standeren; Bathen, Marianne Etzelmüller & Vines, Lasse (2026). Sputtered Aluminum Nitride Thin Films as Waveguides and Hosts for Single-Photon Emitters. Full text in Research Archive Show summary

  AlN is a promising material for hosting quantum emitters and for use as optical waveguides. This work investigates the emission and structural properties of sputtered aluminium nitride thin films, with the aim of integrating these films into a quantum sensor.

• Bygdås, Martin; Zalandauskas, Vytautas; Frøland, Mariann Carlsen; Farsund, Øystein; Vines, Lasse & Bathen, Marianne Etzelmüller (2026). Intrinsic defects in AlN for single-photon emission and spin manipulation. Full text in Research Archive Show summary

  AlN is a promising host for quantum emitters, with an ultra-wide band gap, piezoelectric properties and widely used in industry. Recent reports indicate the presence of single-photon emitters (SPEs) in AlN [1,2], but the responsible defects are unidentified. This work aims to contribute towards such an identification by modelling intrinsic defects in AlN and their magneto-optical properties using density functional theory (DFT).

• Persson, Aksel Faanes; Gjørv, Alexandra Bech; Bernstein, Ralph William; Olsen, Vegard Standeren; Hoofman, Romano & Bathen, Marianne Etzelmüller (2025). Kampen om fremtiden: Mikrobrikker og kvanteteknologi (live-opptak fra teknologifestivalen Kongsberg Agenda 2025). doi: https:/shows.acast.com/smart-forklart/episodes/kampen-om-fremtiden-mikrobrikker-og-kvanteteknologi-live. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Olsen, Vegard Skiftestad & Vines, Lasse (2024). Hvor går veien? Kvanteteknologiens potensiale i fremtidens teknologi​. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Hebnes, Oliver Lerstøl; Schøyen, Øyvind; Winther-Larsen, Sebastian G.; Vines, Lasse & Hjorth-Jensen, Morten (2024). Predicting solid state material platforms for quantum technologies. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Vines, Lasse (2024). Semiconductors as quantum materials - Ongoing research at the LENS group. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Point defects in semiconductors for quantum technologies. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Hvor går veien? Kvanteteknologiens potensiale i fremtidens teknologi. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Hjorth-Jensen, Morten (2024). Where are we going? Quantum technology for future applications. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Doping-induced color centers in Silicon Carbide. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Radiation induced defects in SiC Material and Devices ​. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Deltagelse i Abels Tårn. [Radio]. NRK P2. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Hvorfor kvanteteknologi er det mest spennende du kan drive med. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Thermal formation of vacancy-related defects near the ​ SiO2-SiC interface. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Norway’s green quantum future. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2024). Kvanteteknologiens betydning for samfunnsutviklingen. En ny æra? Full text in Research Archive
• Bathen, Marianne Etzelmüller (2023). Foredrag om MiNaLab og kvanteteknologi for Byråd for kultur og næring i Oslo kommune. Full text in Research Archive
• Ousdal, Erlend Lemva; Bathen, Marianne Etzelmüller & Vines, Lasse (2023). Controlling directionality of emission from quantum defects through microstructures in Silicon Carbide. Full text in Research Archive
• Ousdal, Erlend Lemva; Bathen, Marianne Etzelmüller & Vines, Lasse (2023). Optical and electrical characterization of potential single photon emitters in 6H silicon carbide. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2023). Deltakelse i Abels Tårn, NRK, 03.11.2023. [Radio]. NRK. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2023). How to build a quantum technology platform. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Vines, Lasse (2023). Studieretning i kvanteteknologi​. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Vines, Lasse (2023). Point defects in semiconductors for quantum technologies​ ​ Ongoing research at ​ the University of Oslo​. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2023). QUANTUM COMPUTERS​ How they work and how to make them ​. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Johnson, Brett C.; Galeckas, Augustinas; martins, maria m; Kumar, Piyush & Silkinis, Rokas [Show all 11 contributors for this article] (2023). Doping-induced color centers in silicon carbide ​. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Razinkovas, Lukas; Linderälv, Christopher; Vines, Lasse & Grossner, Ulrike (2023). Quantum pressure sensing using the vibronic spectrum of color centers. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Kumar, Piyush; Ghezellou, Misagh; Belanche, Manuel; Vines, Lasse & Ul-Hassan, Jawad [Show all 7 contributors for this article] (2023). Dual configuration of shallow acceptor levels in 4H-SiC. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Hebnes, Oliver Lerstøl; Schøyen, Øyvind Sigmundson; Winther-Larsen, Sebastian Gregorius; Vines, Lasse & Hjorth-Jensen, Morten (2022). Predicting Solid State Material Platforms for Quantum Technologies. Full text in Research Archive
• Einevoll, Gaute & Bathen, Marianne Etzelmüller (2022). Podcast #63: Om kvantedatamaskiner. [Internet]. Podcast "Vett og vitenskap". Full text in Research Archive
• Galeckas, Augustinas; Karsthof, Robert Michael; Gana, Kingsly; Kok, Angela; Bathen, Marianne Etzelmüller & Vines, Lasse [Show all 7 contributors for this article] (2022). Cross-sectional carrier lifetime profiling and deep level monitoring in silicon carbide films exhibiting variable carbon vacancy concentrations. Full text in Research Archive Show summary

  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.

• Faraj, Sayed; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Myrold, Andreas; Stene-Johansen, Ingar & Jørstad, Øystein Kalsnes [Show all 7 contributors for this article] (2022). Retinal injuries in seven teenage boys from the same handheld laser. American Journal of Ophthalmology Case Reports. 27. doi: 10.1016/j.ajoc.2022.101596. Full text in Research Archive Show summary

  This paper presents retinal injuries in 10 eyes of seven teenagers who had been playing with a handheld laser. They reported different degrees of visual symptoms in the form of central scotomas. Clinical examination revealed light burns in the maculae and disruption of the retinal layers on OCT. One patient developed secondary choroidal neovascularization (CNV), which was successfully treated with intravitreal ranibizumab. For some of the patients, the injuries led to permanent visual sequela. This devastating case series emphasizes the need for awareness among minors, parents and communities about the danger of playing with handheld lasers.

• 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. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Kumar, Piyush; Galeckas, Augustinas; Kuznetsov, Andrej & Vines, Lasse [Show all 7 contributors for this article] (2022). Impact of C-injection in 4H-SiC on defect distribution and minority carrier lifetime. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Kumar, Piyush; Galeckas, Augustinas; Kuznetsov, Andrej Yu. & Vines, Lasse [Show all 7 contributors for this article] (2022). Impact of C-injection in SiC on defect distribution and minority carrier lifetime. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Kumar, Piyush; martins, maria m; Woerle, Judith; Prokscha, Thomas & Grossner, Ulrike (2022). Interaction of in-diffused nitrogen with C and Si lattice sites and vacancies after thermal oxidation and NO annealing. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Enga, Marius Johan; Selnesaunet, Gard Momrak; Kjeldby, Snorre Braathen; Galeckas, Augustinas & Müting, Johanna [Show all 8 contributors for this article] (2022). Charge state control over point defects in SiC devices. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2021). Paneldeltager på radioprogrammet Abels Tårn. [Radio]. NRK P2. Full text in Research Archive Show summary

  Hvorfor blir Creme Fraichen flytende når man rører i den? • Kan man bygge luftskip med vakuum med nye supersterke materialer? • Er det bedre for de snille bakteriene å vaske med eddik? • Alt du (ikke) vil vite om harskt fett • Finnes det materialer som kan stoppe et magnetfelt? • Skal man pusse tenna før eller etter frokost? • Brød fra brødskjæreren: plastpose først, så originalemballasje, eller motsatt? Panelet: Nanoteknolog Marianne Etzelmüller Bathen Kjemiker Einar Uggerud Mikrobiolog Jessica Lönn-Stensrud

• Bathen, Marianne Etzelmüller (2021). Resolving the vibronic fine structure of emission from the silicon vacancy in 4H silicon carbide​. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Linnarsson, Margareta; Galeckas, Augustinas; Kuznetsov, Andrej & Grossner, Ulrike [Show all 7 contributors for this article] (2021). Stability, evolution and diffusion of intrinsic point defects in 4H-SiC. Full text in Research Archive
• 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. Full text in Research Archive
• 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. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2020). Deltagelse i panelet til Radioprogrammet Abels Tårn. [Radio]. NRK P2. Full text in Research Archive Show summary

  Det sies at veps og bier skilte lag og blei til ulike arter da den ene blei kjøtteter og den andre vegetarianer. Kan det samme skje med mennesket? • Kosthold og artsdannelse. Kikertspisere vs kotelettspisere. • Siste nytt fra usynlighetskappefronten • Succusjonens rolle i homøopatien • Hvordan kommer meitemark seg til fjerne øyer? • Er slikkepottrester i maten farlig? • En kortstokk og tilfeldigheter • Hvordan klarte bisonen å ikke bli utrydda? • Tredemølle med stigning vs. løping i ekte motbakke I panelet Nanoteknolog Marianne Etzelmüller Bathen Kjemiker Ole Zwang Paleontolog Lene Liebe Delsett

• Bathen, Marianne Etzelmüller (2020). Deltagelse på Abels Tårn, NRK P2. [Radio]. NRK P2. Full text in Research Archive Show summary

  Hvorfor blir noen IKKE bitt av mygg (til alle andres ergrelse), og hvorfor blir man til spagetti om man hopper ned i et sort hull? Hele menyen: - Kan det bryte ut en helt ny pandemi på romstasjonen? - Hvorfor bærer lyden så godt over vann? - Skyldes pandemier menneskets tukling med naturen? - Kan koronaisolasjon ta knekken på andre sjukdommer? - Kan virus og bakterier bli resistente mot antibac? - Hvorfor bryter Newtons lover sammen i ekstreme situasjoner? - Sjefer som ikke blir bitt av mygg - Vokser håret mer når man sover? - Er elbiler virkelig klimavennlige også i land med BARE kullkraft? - Blir insekter gamle og grå som oss? I panelet: Insektøkolog Anne Sverdrup Thygeson Fysiker Marianne Etzelmüller Bathen Lege Steinar Madsen

• Bathen, Marianne Etzelmüller & Olsen, Vegard Skiftestad (2020). Foredrag for MENA-studenter om halvlederfysikk. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Olsen, Vegard Skiftestad (2020). Foredrag for FA-studenter om halvlederfysikk. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2019). Kvantedatamaskiner - prinsipp, funksjon, og hvordan de nokså enkelt kan lages på labben. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Caroline, Enge (2019). Norske studenter lager spill til «den neste store teknologien»: Kvantedatamaskinen. [Journal]. Aftenposten. Full text in Research Archive Show summary

  Vemund Falch og Christian Johnsens sommerjobb er å lage et pokerspill som kan brukes på en kvantedatamaskin. I verden foregår et kappløp for å forstå hva annet maskinene kan brukes til.

• Bathen, Marianne Etzelmüller & Olsen, Vegard Skiftestad (2019). Omvisning for FA og ELITE. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2019). Abels Tårn. [Radio]. NRK P2. Full text in Research Archive Show summary

  Nå står kampen om gruveavfall i Repparfjorden. Men gruven skal produsere både kobber og sølv som brukes i solceller. Er det egentlig bærekraftig å skulle produsere nok solceller til å erstatte all verdens fosile energikilder? - Hvis man tar stikling av en stikling av en stikling etc - er det da samme plante 1000 år seinere? - Noen sier det går strøm i telefonladere som står i, gjør det det? - Er egentlig solceller bærekraftig - når man ser på metallene som brukes for å lage dem? - Hvorfor står det Aloe barbadensis på innholdsfortegnelsen på Aloe vera produkter? - Hvordan kan en qbit være både 0 og 1 på en gang? I panelet: Botaniker Charlotte Sletten Bjorå Elektroingeniør Sverre Holm Kvantefysiker/nanoteknolog Marianne Etzelmüller Bathen

• Bathen, Marianne Etzelmüller; Borgersen, Jon Arthur; Karlsen, Kjetil; Nyborg, Martin; Olsen, Vegard Skiftestad & Reinertsen, Vilde Mari [Show all 7 contributors for this article] (2019). Skolebesøk ved MiNaLab. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2019). Kvantedatamaskiner - prinsipp, funksjon, og hvordan de nokså enkelt kan lages på labben. Full text in Research Archive Show summary

  Datamaskiner styrer en stadig større del av hverdagen vår, og når bruken av digitale verktøy øker, trenger vi også kraftigere datamaskiner. Det finnes haugevis av oppgaver som dagens superdatamaskiner enten er for svake til, eller ikke laget for, å gjøre. Forskere over hele verden jobber med dette problemet, og kvantedatamaskiner har seilt frem som en mulig løsning. Men, kvantedatamaskinene som har blitt laget så langt, er bygd opp av veldig få såkalte kvantebits. Disse lages av dyre materialer, er veldig vanskelige å lage og kan kun operere ved ekstremt lave temperaturer. Derfor ønsker man å finne et bedre alternativ, for eksempel ved å bruke halvledermaterialer, som ellers brukes som transistorer, lys-emitterende dioder og solceller. Marianne Etzelmüller Bathen er forsker ved Fysisk institutt, og jobber med å lage og kontrollere kvantebits i halvledere. Hun vil snakke om hvordan de nye kvantedatamaskinene fungerer, hva de kan brukes til, hvordan de skiller seg fra de gamle og hvordan hun og hennes kolleger jobber for å legge grunnlaget for en fremtidig IT-revolusjon.

• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Müting, Johanna; Ayedh, Hussein Mohammed Hussein; Grossner, Ulrike & Coutinho, J [Show all 7 contributors for this article] (2019). Electrical enhancement and switching of single-photon emission from the silicon vacancy in 4H-SiC. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2019). The future of quantum computing: Beyond the superconducting paradigm. Full text in Research Archive
• Bathen, Marianne Etzelmüller (2019). Intervju av TV2 Nyhetskanalen, kl 0710, om kvantedatamaskiner. [TV]. TV2 Nyhetskanalen. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Jemterud, Torkild (2019). Abels Tårn. [Radio]. NRK P2. Full text in Research Archive
• Bathen, Marianne Etzelmüller & Vines, Lasse (2019). Point defects in semiconductors for quantum technology: Example of silicon vacancy in silicon carbide. Full text in Research Archive
• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Müting, Johanna; Ayedh, Hussein Mohammed Hussein; Grossner, Ulrike & Coutinho, José [Show all 7 contributors for this article] (2019). Electrical enhancement and switching of single-photon emission from the silicon vacancy in 4H-Si. Full text in Research Archive Show summary

  The high-spin ground state and bright single-photon emission of the silicon vacancy (VSi) in 4H-SiC offer exciting possibilities for quantum technology and spintronics applications, especially as both are available at room temperature [1,2]. However, quantum compatibility only exists for the singly negative VSi, and single-photon counts are still too low to realize efficient spin-photon interfaces without resorting to complex nanofabrication methods [3]. Herein, we demonstrate enhanced optical emission from VSi using Schottky barrier diode (SBD) formation, and attribute our findings to increased occupancies of VSi-1.

• Bathen, Marianne Etzelmüller & Jemterud, Torkild (2019). Abels tårn. [Radio]. NRK P2. Full text in Research Archive Show summary

  En lytter fra Nord-Norge vil gjerne få nok luft, men slippe en halv meter snø inn gjennom soveromsvinduet på vinteren. Kan potteplanter gjøre susen? - Potteplanter som oksygenprodusenter på soverommet - Nanosvamper fjerner grønske på terrassen - Er det en dag i året der sola står opp på likt langs en hel lengdegrad? - Skyldes årets enorme mengder fnokk tørkestress fra forrige sommer? - Hvorfor kommer det blod og fiskesøl ut av tinende poser fra fryseren? - "Ingen regel uten unntak", heter det. Et paradoks? - Hvordan kan vaniljerot være en plante, når den ikke har klorofyll? I panelet: Botaniker Charlotte Sletten Bjorå Nanoteknolog Marianne Bathen Matematiker Andreas Nakkerud

• Enga, Marius Johan; Vines, Lasse & Bathen, Marianne Etzelmüller (2021). Exploring Defects in Silicon Carbide for Quantum Technologies; A Density Functional Theory Study. Universitetet i Oslo. Full text in Research Archive
• Selnesaunet, Gard Momrak; Vines, Lasse & Bathen, Marianne Etzelmüller (2021). Nanostructuring of SiC for novel defect-based quantum technologies. Universitetet i Oslo. Full text in Research Archive Show summary

  Point defects in semiconductors have emerged as viable candidates for quantumbased technologies such as quantum computing, communication, and sensing. The present work is related to quantum compatible point defects in silicon carbide (SiC), particularly the silicon vacancy, a point defect and material system that has received considerable research interest in the last few years. In this thesis, a fabrication process was developed for producing structures in SiC that can be used as, e.g., waveguides for single-photon emission. This was performed by depositing a SiO2 layer with plasma chemical vapor deposition (PECVD) on a high purity 4H-SiC wafer. Next, with photolithography, the SiO2 layer was patterned with a photoresist mask in a reactive ion etching (RIE) step. The patterned SiO2 layer was then used as a hard mask for a subsequent RIE step, finalizing the photonic device. A thin nickel layer was deposited on the structures with physical vapor deposition (PVD) for the charge-state control through a liftoff process with a photoresist mask. Defect creation was achieved by 21 keV He implantation to a fluence of 1×1011 cm−2 with an ion implanter. In a scanning electron microscope (SEM), the device morphology showed sharply defined features with almost vertical sidewalls. The diffraction limit from the photolithography resulted in increasingly tilted sidewalls as the structures decreased in size. The optical properties were characterized with cathodoluminescence (CL) spectroscopy and exhibited emission in the V1 and V1’ zero-phonon lines (ZPLs) associated with the VSi. Charge-state control of the VSi was identified by enhancing the V− Si CL emission intensity in the depletion region of the Schottky contact, with a reduction in intensity towards the depletion region edge. By utilizing angle-resolved cathodoluminescence (ARCL) spectroscopy, the radiation profiles of the photonic structures were shown to be altered compared to the Lambertian radiation profile of the implanted wafer. Though no electromagnetic wave propagation in discrete modes (waveguiding effect) was observed, the photonic devices enhanced the emission intensity of the VSi in all directions by functioning as a lens with a higher numerical aperture than the wafer, and the lens had characteristics similar to a combination of a solid immersion lens (SIL) and an optical fiber. The findings presented herein are important for further photonic device fabrication in 4H-SiC, and lay the groundwork for incorporating quantum compatible point defects in electrically driven quantum technology devices.

• Bathen, Marianne Etzelmüller (2020). Point defects in silicon carbide for quantum technologies: Identification, tuning and control. Universitetet i Oslo. Full text in Research Archive Show summary

  Point defects strongly affect the electrical and optical properties of semiconductors, and are therefore of vast importance for device performance. Over recent years, however, point defects have been shown to possess properties that are highly suitable for applications related to quantum computing, sensing and communication. Single-photon emission and coherent spin manipulation at room temperature have been established for several systems, with the nitrogen-vacancy center in diamond counting among the first solid-state and semiconductor-based quantum platforms. Despite the long coherence times and established entanglement protocols of diamond-based qubit systems, diamond is only marginally compatible with advanced device fabrication methodology, and methods for integration of quantum emitters with electrically and optically controlled devices remain immature. For this reason, silicon carbide (SiC) has gained the attention of the quantum community, having a wide band gap, low spin-orbit coupling, mature device fabrication, and playing host to several promising quantum emitters of both extrinsic and intrinsic type. In this work, electrically and optically active point defects in silicon carbide have been studied using a combination of theoretical and experimental methods, with the aim of elucidating the role of different defects in power electronics and quantum technology devices. Hybrid density functional theory (DFT) calculations were employed to establish defect formation energies and chargestate transition levels, explore defect migration, and develop a new framework for studying the effect of electric fields on defect quantum emission. The calculations are correlated to experimental findings, where deep level transient spectroscopy (DLTS) and photo/cathodoluminescence (PL/CL) measurements reveal electrical and optical defect properties, respectively. The thesis places a particular emphasis on the silicon vacancy (VSi) in SiC, a room temperature single-photon source and qubit candidate exhibiting long spin coherence times. By monitoring VSi emission and comparing to DLTS spectra of proton-irradiated 4H-SiC samples, the VSi(-/2-) and VSi(2-/3-) charge-state transitions are assigned to the S-center, enabling electrical control over the VSi charge state. Depositing Schottky barrier diodes (SBDs) on the 4H-SiC sample surface enhances VSi emission by almost an order of magnitude, and sequential biasing of the SBD results in VSi charge-state switching, as detected by monitoring the V1 and V10 zero-phonon lines attributed to the negatively charged VSi at a hexagonal lattice site. The framework of bulk 4H-SiC epitaxial layers is compared to that of a microparticle matrix of predominantly the 6H polytype, with the former ensuring a homogeneous environment for the qubit defect and the latter enabling self-assembly, flexibility and ease of addressability. Importantly, both external and internal perturbations to the solid-state matrix wherein the VSi is embedded are shown to influence the emitted photon energies, as evidenced by an electric field-induced Stark effect and strain tuning in SiC microparticles. Furthermore, a set of emitters observed in the vicinity of the V1/V10 lines and having consistent subset spacings of 1.45 meV and 1.59 meV are tentatively attributed to vibronic replicas of the VSi emission. The VSi is unstable at elevated temperatures, and this thesis addresses the topics of VSi conversion and defect migration in p-type, intrinsic and n-type 4H-SiC material at 400 °C and above. Indeed, we find that hydrogen and VSi are likely to form complexes in the case that both species are present and in close proximity. In the absence of H, the VSi may convert to the carbon antisitevacancy (CAV) pair in p-type material, however, temperatures above 1000 °C are needed in n-type 4H-SiC, where both recombination with interstitials and divacancy formations prove to be more favorable annealing pathways for the VSi. The carbon vacancy (VC) is far more stable than VSi, and by comparing the two defect species using muon spin rotation (μSR) spectroscopy, we establish the μSR technique as a powerful tool for distinguishing different defect relaxation mechanisms and probing near-surface semiconductor defects in a non-destructive and depth-resolved manner. Annealing temperatures above 1200 °C are shown to be needed to induce VC migration, which is further demonstrated to be anisotropic in 4H-SiC, with the VC favoring in-plane atomic hops over the axial migration path. Finally, above temperatures of 2300 °C the lattice atoms themselves become mobile, and secondary ion mass spectrometry (SIMS) is employed to investigate the influence of a carbon cap covering the surface during annealing on self-diffusion of Si and C in 4H-SiC.

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