Ole Bjørn Karlsen

• Garcia Fernandez, Javier; Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; Karlsen, Ole Bjørn; Vines, Lasse & Prytz, Øystein (2022). Formation of γ-Ga2O3 by ion implantation: Polymorphic phase transformation of β-Ga2O3. Applied Physics Letters. ISSN 0003-6951. 121(19). doi: 10.1063/5.0120103. Full text in Research Archive
• Kosinskiy, Andrey; Karlsen, Ole Bjørn; Sørby, Magnus Helgerud & Prytz, Øystein (2016). Ternary Phases (Heusler) in the System Ti-Co-Sn. Metallurgical and Materials Transactions E. ISSN 2196-2936. 3(4), p. 329–336. doi: 10.1007/s40553-016-0098-5. Full text in Research Archive
• Sottmann, Jonas; Valset, Kjetil; Karlsen, Ole Bjørn & Taftø, Johan (2013). Synthesis and Measurement of the Thermoelectric Properties of Multiphase Composites: ZnSb Matrix with Zn4Sb3, Zn3P2, and Cu5Zn8. Journal of Electronic Materials. ISSN 0361-5235. 42(7), p. 1820–1826. doi: 10.1007/s11664-012-2441-7.
• Song, Xin; Böttger, Paul Heinrich Michael; Karlsen, Ole Bjørn; Finstad, Terje & Taftø, Johan (2012). Impurity band conduction in the thermoelectric material ZnSb. Physica Scripta. ISSN 0031-8949. T148. doi: 10.1088/0031-8949/2012/T148/014001.
• Böttger, Paul Heinrich Michael; Flage-Larsen, Espen; Karlsen, Ole Bjørn & Finstad, Terje (2012). High temperature Seebeck coefficient and resistance measurement system for thermoelectric materials in the thin disk geometry. Review of Scientific Instruments. ISSN 0034-6748. 83(2). doi: 10.1063/1.3673474.
• Prytz, Øystein; Gunnæs, Anette Eleonora; Karlsen, Ole Bjørn; Breivik, Tallak Harald; Toberer, E. S. & Snyder, G. J. (2009). Nanoscale inclusions in the phonon glass thermoelectric material Zn4Sb3. Philosophical Magazine Letters. ISSN 0950-0839. 89(6), p. 362–369. doi: 10.1080/09500830902950464.
• Karlsen, Ole Bjørn; Kjekshus, Arne; Fjellvåg, Helmer; Ravindran, Ponniah; Vidya, R. & Hauback, BC (2009). Structure and magnetism of the beta-Mn-Co solid-solution phase. Journal of Alloys and Compounds. ISSN 0925-8388. 476(1-2), p. 9–13. doi: 10.1016/j.jallcom.2008.09.011.
• Diplas, Spyridon; Prytz, Øystein; Karlsen, Ole Bjørn; Watts, JF & Taftø, Johan (2007). A quantitative study of valence electron transfer in the skutterudite compound CoP3 by combining x-ray induced Auger and photoelectron spectroscopy. Journal of Physics: Condensed Matter. ISSN 0953-8984. 19. doi: 10.1088/0953-8984/19/24/246216.
• Nilsen, Ola; Karlsen, Ole Bjørn; Kjekshus, Arne & Fjellvåg, Helmer (2007). Simulation of growth dynamics in atomic layer deposition. Part I. Amorphous films. Thin Solid Films. ISSN 0040-6090. 515. doi: 10.1016/j.tsf.2006.11.023.
• Nilsen, Ola; Karlsen, Ole Bjørn; Kjekshus, Arne & Fjellvåg, Helmer (2007). Simulation of growth dynamics in atomic layer deposition. Part II. Polycrystalline films from cubic crystallites. Thin Solid Films. ISSN 0040-6090. 515. doi: 10.1016/j.tsf.2006.11.024.
• Nilsen, Ola; Karlsen, Ole Bjørn; Kjekshus, Arne & Fjellvåg, Helmer (2007). Simulation of growth dynamics in atomic layer deposition. Part III. Polycrystalline films from tetragonal crystallites. Thin Solid Films. ISSN 0040-6090. 515. doi: 10.1016/j.tsf.2006.11.025.
• Nilsen, Ola; Karlsen, Ole Bjørn; Kjekshus, Arne & Fjellvåg, Helmer (2007). Simulation of growth dynamics for nearly epitaxial films. Journal of Crystal Growth. ISSN 0022-0248. 308, p. 366–375. doi: 10.1016/j.jcrysgro.2007.08.001.
• Hansen, Vidar; Karlsen, Ole Bjørn; Langsrud, Yngve & Gjønnes, Jon (2004). Precipitates, zones and transitions during aging of Al-Zn-Mg-Zr7000series alloy. Materials Science and Technology. ISSN 0267-0836. 20, p. 185–193.
• Hansen, Vidar; Karlsen, Ole Bjørn; Langsrud, Yngve & Gjønnes, Jon (2004). Precipitates, zones and transitions during ageing of Al-Zn-Mg-Zr 7000 series alloy. Materials Science and Technology. ISSN 0267-0836. p. 185–193.
• Hansen, V; Karlsen, Ole Bjørn; Langsrud, Y & Gjonnes, J (2004). Precipitates, zones and transitions during aging of Al-Zn-Mg-Zr7000series alloy. Materials Science and Technology. ISSN 0267-0836. 20, p. 185–193.
• Walle, Christin; Torgersen, Alexandra Neumann; Karlsen, Ole Bjørn; Kjekshus, Arne & Klewe, Bernt (2000). The ternary system Au-Cr-Sn and the crystal structure of Au1.15Cr2Sn8.85. Journal of Alloys and Compounds. ISSN 0925-8388. 308, p. 126–133.
• Karlsen, Ole Bjørn; Kjekshus, Arne & Røst, Erling (1992). The ternary system Au-Cu-Sn. Acta Chemica Scandinavica. ISSN 0904-213X. 46, p. 147–156.
• Karlsen, Ole Bjørn; Kjekshus, Arne; Rømming, Hans Christian & Røst, Erling (1992). The crystal-structure of the low-temperature Au80-xCuxSn20. Acta Chemica Scandinavica. ISSN 0904-213X. 46, p. 1076–1082.
• Karlsen, Ole Bjørn; Kjekshus, Arne; Rømming, Hans Christian & Røst, Erling (1992). The crystal-structure of AuCuSn. Acta Chemica Scandinavica. ISSN 0904-213X. 46, p. 442–445.
• Karlsen, Ole Bjørn; Kjekshus, Arne & Røst, Erling (1990). Ternary phases in the system Au-Cu-Sn. Acta Chemica Scandinavica. ISSN 0904-213X. 44, p. 197–198.

View all works in Cristin

• Finstad, Terje Gunnar; Mayandi, Jeyanthinath & Karlsen, Ole Bjørn (2023). Thermoelectric Multi-pnictogens Semiconductors: Cu Doping of ZnSbAs Alloys.
• Mayandi, Jeyanthinath; Soltani, Nayereh; Finstad, Terje Gunnar; Karlsen, Ole Bjørn & Flage-Larsen, Espen (2022). Zinc Multi-Pnictogens Semiconductors: Cu Doping and Thermoelectric Characteristics.
• Løberg, Monika; Karlsen, Ole Bjørn; Løvvik, Ole Martin; Almeida Carvalho, Patricia & Gunnæs, Anette Eleonora (2019). Characterization of phase transformations within the Cu-Pd-Sn system - a possible shape memory alloy for energy conversion.
• Løberg, Monika; Pike, Nicholas; Almeida Carvalho, Patricia; Karlsen, Ole Bjørn; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2019). Martensitic-like phase transformations within the Cu-Pd-Sn system .
• Løberg, Monika; Løvvik, Ole Martin; Almeida Carvalho, Patricia; Karlsen, Ole Bjørn & Gunnæs, Anette Eleonora (2019). Phase Transformations within the Cu-Pd-Sn system.
• Løberg, Monika; Pike, Nicholas; Karlsen, Ole Bjørn; Almeida Carvalho, Patricia; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2019). Characterization of phase transforming, Heusler based (Cu-Pd-Sn), alloys for energy harvesting. .
• Sunding, Martin Fleissner; Løberg, Monika; S. Azar, Amin; Stange, Marit Synnøve Sæverud; Almeida Carvalho, Patricia & Karlsen, Ole Bjørn [Show all 10 contributors for this article] (2019). The Need for a Multi-Technique Approach in the Search for New Phase-Transforming Materials. Show summary

  Introduction/Purpose Reversible diffusionless first-order phase transformations are a fundamental part of phase change materials and shape memory alloys [1]. Some of these materials even possess useful physical characteristics that show abrupt changes e.g. in their electrical[2] and magnetic [3] polarizations. These phase transformations can be studied using multiple techniques, enabling access to different types of information including length scales and time periods, but how should this characterisation be approached? Methods TEM studies give highly relevant data in this field of research, from detailed crystallographic structures, to relative orientations between grains and phases and to the phase transformation temperature. However, TEM analyses are time consuming and requires small sample sizes and ad hoc preparation. High-throughput measurement techniques are thus required in the search for improved compositions and new materials in order to rapidly assess the properties of many samples or samples with graded composition [4]. Optical methods (for example unpolarised and polarised microscopy and thermal imaging) and electric conductivity measurements can for example be used to map phase transformation temperatures much faster and on much larger areas than traditional TEM techniques. XRD and SEM-EDS-EBSD can then be applied to obtain initial crystallographic and microstructure information on an intermediate size scale, before TEM is applied for the in-depth study of the most relevant compositions. Results We applied this multi-pronged approach in the search for Heusler and half-Heusler alloys with a low temperature martensitic phase transformation and with low thermal hysteresis, with potential applications in waste heat energy harvesting. Conclusions Drawing advantage of the strengths of multiple analysis techniques – with respect to the obtainable information, the sample size and/or the time frame of the analyses – renders the search for new phase change materials more effective. It enables faster identification of potential target compositions and of sample areas optimal for in depth studies. Selected references [1] David Dye, Nature Materials14 (8), 760 (2015). [2] M. M. Vopson, Critical Reviews in Solid State and Materials Sciences40 (4), 223 (2015). [3] L. Huang, D. Y. Cong, L. Ma, Z. H. Nie, Z. L. Wang, H. L. Suo, Y. Ren, and Y. D. Wang, Applied Physics Letters108 (3) (2016). [4] M. L. Green, C. L. Choi, J. R. Hattrick-Simpers, A. M. Joshi, I. Takeuchi, S. C. Barron, E. Campo, T. Chiang, S. Empedocles, J. M. Gregoire, A. G. Kusne, J. Martin, A. Mehta, K. Persson, Z. Trautt, J. Van Duren, and A. Zakutayev, Applied Physics Reviews 4 (1), 011105 (2017).

• Haug, Kristian; Nguyen, Phuong Dan; Karlsen, Ole Bjørn; Aarholt, Thomas; Bazioti, Kalliopi & Prytz, Øystein (2019). Zinc ferrite spinel embedded in ZnO matrix for solar applications.
• Prytz, Øystein; Karlsen, Ole Bjørn; Nguyen, Phuong Dan; Carvalho, Patricia A. & Lundell, Martin Egge (2018). Illustrert vitenskap. [Journal]. Bilder.
• Song, Xin; Persson, Clas; Norby, Truls; Flage-Larsen, Espen; Karlsen, Ole Bjørn & Hansen, Vidar [Show all 15 contributors for this article] (2014). Conversion of Heat and Energy: Thermoelectrics.
• Kosinskiy, Andrey; Prytz, Øystein; Karlsen, Ole Bjørn & Sørby, Magnus Helgerud (2014). X-ray and neutron diffraction study of Co(2-x)TiSn [x < 0.5] solid solution.
• Løvvik, Ole Martin; Song, Xin; Valset, Kjetil; Flage-Larsen, Espen; Fjeld, Harald & Graff, Joachim Seland [Show all 14 contributors for this article] (2014). Thermoelectric materials from first principles to final applications: Basic and applied thermoelectrics in Oslo.
• Song, Xin; Valset, Kjetil; Karlsen, Ole Bjørn; Graff, Joachim Seland; Thøgersen, Annett & Luxsacumar, Sivakanesar [Show all 7 contributors for this article] (2013). Characterization methods for nanostructured thermoelectric materials ZnSb.
• Song, Xin; Karlsen, Ole Bjørn; Valset, Kjetil; Løvvik, Ole Martin & Finstad, Terje (2013). STUDIES ON SULPHUR DOPING OF ZnSb.
• Qureishy, Thomas; Hansen, Vidar; Karlsen, Ole Bjørn; Gunnæs, Anette Eleonora & Taftø, Johan (2012). Superstructures in Mg2Si1-xSnx.
• Løvvik, Ole Martin; Valset, Kjetil; Rauwel, Protima; Prytz, Øystein; Flage-Larsen, Espen & Song, Xin [Show all 11 contributors for this article] (2012). Thermoelectricity in Oslo.
• Song, Xin; Karlsen, Ole Bjørn; Taftø, Johan; Böttger, Paul Heinrich Michael & Finstad, Terje (2011). Electrical and structural characterization of thermoelectric material ZnSb with additions of Mn and Cr.
• Song, Xin; Valset, Kjetil; Böttger, Paul Heinrich Michael; Karlsen, Ole Bjørn; Finstad, Terje & Taftø, Johan (2011). Structure and Thermoelectric Properties of Cr and Mn Doped ZnSb.
• Böttger, Paul Heinrich Michael; Valset, Kjetil; Flage-Larsen, Espen; Prytz, Øystein; Bording, Jan Kåre & Karlsen, Ole Bjørn [Show all 9 contributors for this article] (2009). An overview of our basic and applied thermoelectric research activity.
• Valset, Kjetil; Böttger, Paul Heinrich Michael; Karlsen, Ole Bjørn & Taftø, Johan (2009). Microstructure and thermoelectric property studies of ZnSb with Sb and Zn4Sb3 inclusions.
• Böttger, Paul Heinrich Michael; Valset, Kjetil; Karlsen, Ole Bjørn; Deledda, Stefano & Finstad, Terje (2009). The Effect of Nanostructuring on the Thermoelectric Properties of ZnSb.
• Stølen, Svein; Karlsen, Ole Bjørn & Vedde, John Øivind (2008). Mange bidragsytere.
• Prytz, Øystein; Flage-Larsen, Espen; Karlsen, Ole Bjørn; Diplas, Spyridon; Finstad, Terje & Taftø, Johan [Show all 11 contributors for this article] (2007). Electronic structure of thermoelectric skutterudites; combining spectroscopic techniques, precision electron diffraction and density functional theory.
• Karlsen, Ole Bjørn (2007). Skutterudite: from a rare mineral to hot thermoelectric materials.
• Nilsen, Ola; Karlsen, Ole Bjørn & Fjellvåg, Helmer (2007). Simulation of growth dynamics for nearly epitaxial films.
• Nilsen, Ola; Karlsen, Ole Bjørn; Kjekshus, Arne & Fjellvåg, Helmer (2006). Simulation of ALD growth dynamics.
• Bergli, Jørgen; Prytz, Øystein; Nguyen, Phuong Dan & Karlsen, Ole Bjørn (2021). Solid state precipitation of spinels in zinc oxide - A microstructure study. Universitetet i Oslo. Show summary

  In this work we have investigated the possibility for solid state precipitation of spinel crystals in zinc oxide by separate addition of three different dopant elements. These dopant elements were iron, antimony and vanadium, and were generally introduced as oxide powders. The dopant compounds were mixed with zinc oxide using a powder synthesis route, where the annealing temperature was mostly kept below the solidus temperature in the given system. Some experiments were also performed using a single crystal of zinc oxide embedded in iron oxide and zinc oxide powders. These samples are referred to as diffusion couples. The characterization of samples was carried out by adopting several observation methods. That is light microscopy, x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy and scanning transmission electron microscopy. This variety of methods enabled complementary information to be obtained. It was found that the zinc oxide – iron system displays the most promising features in regard to precipitating spinels crystals in the zinc oxide matrix. This property is attributed to a highly temperature dependent solid solubility of iron in zinc oxide. Observations made in this system indicate that two different spinel forming mechanisms are possible. One includes a high solute iron concentration in zinc oxide and consequently precipitation during cooling of the sample. In the other route a second annealing step is added to promote the precipitation from a somewhat low iron concentration in the zinc oxide matrix. The physical appearance of the precipitates was different depending on precipitation route, however the same orientation relationship with adjacent zinc oxide grains/matrix was found for both spinel precipitates. In addition, iron rich inversion domain boundaries were seen in the single crystal. These were explored, and it was found that the spacing between the domains matched the iron concentration profile in the same region. The transition from inversion domain boundaries to spinel grains was probed to understand nucleation mechanisms for both features. In the two other systems, antimony and vanadium doped zinc oxide, no precipitations were found. However, it was found that zinc oxide had low and more or less constant solid solubility when temperature was varied in these systems, which is assumed to be a determining factor in limiting the possibility for precipitations. Therefore, attempts were done in the zinc oxide – vanadium system to increase the solubility. However, despite interesting synthesis development, we were not able to increase the solid solubility. In the zinc oxide – antimony system we show that etching of surfaces could be a way to render inversion domain boundaries visible in scanning electron microscopes. We also confirm the volatility of antimony by the use of x-ray diffraction and energy dispersible spectroscopy.

• Wiken Langfeldt, Sindre; Prytz, Øystein; Karlsen, Ole Bjørn & Nguyen, Phuong Dan (2015). Syntese og karakterisering av termoelektriske halv-Heusler materialer av typen (Ti,Zr,Hf)NiSn. Universitetet i Oslo.
• Kosinskiy, Andrey; Prytz, Øystein; Karlsen, Ole Bjørn & Sørby, Magnus Helgerud (2014). Syntese- og diffraksjonsstudie av faser i systemene Nb–Fe–Sb og Ti–Co–Sn. Universitetet i Oslo.
• Hansen, Vidar; Karlsen, Ole Bjørn & Gjønnes, Jon (2001). Utbredelse av soner og herdepartikler i 7108.70; transmisjonselektronmikroskopi og differensiell skanning kalorimetri.

View all works in Cristin