thomasaar

• Kang, Xiaolan; Chatzitakis, Athanasios; Aarholt, Thomas; Sun, Xinwei; Negri, Chiara & Norby, Truls (2022). Facet-engineered TiO<inf>2</inf>nanomaterials reveal the role of water-oxide interactions in surface protonic conduction. Journal of Materials Chemistry A. ISSN 2050-7488. 10(1), p. 218–227. doi: 10.1039/d1ta06075a.
• Zhu, Junjie; Gudmundsdottir, Jonina Björg; Strandbakke, Ragnar; Both, Kevin Gregor; Aarholt, Thomas & Almeida Carvalho, Patricia [Show all 12 contributors for this article] (2021). Double Perovskite Cobaltites Integrated in a Monolithic and Noble Metal-Free Photoelectrochemical Device for Efficient Water Splitting. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(17), p. 20313–20325. doi: 10.1021/acsami.1c01900. Full text in Research Archive
• Liu, Junliang; Li, Kexue; Sayers, James; Aarholt, Thomas; He, Guanze & Hulme, Helen [Show all 14 contributors for this article] (2020). Characterisation of deuterium distributions in corroded zirconium alloys using high-resolution SIMS imaging. Acta Materialia. ISSN 1359-6454. 200, p. 581–596. doi: 10.1016/j.actamat.2020.09.040. Full text in Research Archive
• Hansen, Per-Anders Stensby; Zikmund, Tomas; Yu, Ting; Kvalvik, Julie Nitsche; Aarholt, Thomas & Prytz, Øystein [Show all 8 contributors for this article] (2020). Single-step approach to sensitized luminescence through bulk-embedded organics in crystalline fluorides. Communications chemistry. ISSN 2399-3669. 3. doi: 10.1038/s42004-020-00410-0. Full text in Research Archive
• Bonkerud, Julie; Zimmermann, Christian; Weiser, Philip Michael; Aarholt, Thomas; Verhoeven, Espen Førdestrøm & Vines, Lasse [Show all 8 contributors for this article] (2020). Fabrication and characterization of Schottky barrier diodes on rutile TiO2. Materials Research Express. ISSN 2053-1591. 7(6). doi: 10.1088/2053-1591/ab9777. Full text in Research Archive
• Aarholt, Thomas; Frodason, Ymir Kalmann & Prytz, Øystein (2020). Imaging defect complexes in scanning transmission electron microscopy: Impact of depth, structural relaxation, and temperature investigated by simulations. Ultramicroscopy. ISSN 0304-3991. 209. doi: 10.1016/j.ultramic.2019.112884. Full text in Research Archive
• Sky, Thomas Neset; Johansen, Klaus Magnus H; Frodason, Ymir Kalmann; Aarholt, Thomas; Riise, Heine Nygard & Prytz, Øystein [Show all 8 contributors for this article] (2019). Diffusion of indium in single crystal zinc oxide: a comparison between group III donors. Semiconductor Science and Technology. ISSN 0268-1242. 34(2), p. 1–6. doi: 10.1088/1361-6641/aafa4c. Full text in Research Archive
• Kexue, Li; Aarholt, Thomas; Liu, Junliang; Hulme, Helen; Garner, Alistair & Preuss, Michael [Show all 8 contributors for this article] (2019). 3D-characterization of deuterium distributions in zirconium oxide scale using high-resolution SIMS. Applied Surface Science. ISSN 0169-4332. 464, p. 311–320. doi: 10.1016/j.apsusc.2018.09.101. Full text in Research Archive
• Pedrazzini, S; Child, DJ; Aarholt, Thomas; Ball, C; Dowd, M & Girling, A [Show all 11 contributors for this article] (2018). On the Effect of Environmental Exposure on Dwell Fatigue Performance of a Fine-Grained Nickel-Based Superalloy. Metallurgical and Materials Transactions A. ISSN 1073-5623. 49(9), p. 3908–3922. doi: 10.1007/s11661-018-4752-7. Full text in Research Archive
• Granerød, Cecilie Skjold; Bilden, Sindre Rannem; Aarholt, Thomas; Yao, Yu-Feng; Yang, C. C. & Look, David C. [Show all 9 contributors for this article] (2018). Direct observation of conduction band plasmons and the related Burstein-Moss shift in highly doped semiconductors: A STEM-EELS study of Ga-doped ZnO. Physical review B (PRB). ISSN 2469-9950. 98(11). doi: 10.1103/PhysRevB.98.115301. Full text in Research Archive
• Sønsteby, Henrik Hovde; Aarholt, Thomas; Prytz, Øystein; Fjellvåg, Helmer & Nilsen, Ola (2018). First Complex Oxide Superconductor by Atomic Layer Deposition. Chemical Communications. ISSN 1359-7345. 54(59), p. 8253–8256. doi: 10.1039/c8cc04998j.
• Zhan, Wei; Venkatachalapathy, Vishnukanthan; Aarholt, Thomas; Kuznetsov, Andrej & Prytz, Øystein (2018). Band gap maps beyond the delocalization limit: correlation between optical band gaps and plasmon energies at the nanoscale. Scientific Reports. ISSN 2045-2322. 8(848), p. 1–7. doi: 10.1038/s41598-017-18949-9. Full text in Research Archive

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• Aarholt, Thomas; Both, Kevin Gregor; Reinertsen, Vilde Mari & Prytz, Øystein (2021). Surface plasmon investigations by STEM-EELS mapping of Au/Ni nanoparticles on STO. Show summary

  Metallic nanoparticles have traditionally had sharp absorption peaks between 1 and 5 eV due to the excitation of surface plasmons. Localized surface plasmon resonance (LSPR) is the coherent oscillation of quasi-free electrons excited by the electromagnetic fields of a photon or fast electron1,2. Since the absorption peak energies are in the range of visible light, surface plasmons present a potential pathway for absorbing energy to drive photoelectrochemical reactions or contribute to photovoltaic applications. For driving photoelectrochemical reactions, one difficulty is placing photoactive nanoparticles near the catalyst responsible for a chosen reaction, for example, water splitting. The ideal semiconductor for water splitting has a bandgap of 1.9 – 2.3 eV, although semiconductors in this range are seldom stable during photocatalytic water splitting3. Utilizing plasmonics in wide bandgap semiconductors is a promising alternative, avoiding the stability issue3. In this work, we present a STEM-EELS study of Au nanoparticles created by galvanic replacement of Ni nanoparticles grown by exsolution of a PLD-deposited thin-film of A-site excess strontium titanate (Sr1.07Ti 0.93Ni0.07O 3-δ) (STO). STO is an indirect, wide bandgap (3.2 eV) perovskite, studied as a promising photocatalyst for water splitting 4. Ni can easily substitute the Ti in the STO, making it a suitable candidate for exsolution, while Au cannot substitute Ti5. Simultaneously, Ni nanoparticles barely show any plasmonic activities, while Au particles are second only to Ag nanoparticles6. The presented manufacturing technique results in nanoparticles of gold and nickel freestanding, but socketed, on the surface and embedded in the bulk, with diameters between 50 and 100 nm, which are well-suited for plasmonic applications. As a starting point, STEM-EELS was performed with a monochromated 300kV STEM probe with ZeroLoss Peak (ZLP) full-width at half-maximum of 110 meV on an FEI Titan G2. A peculiarly shaped gold nanocluster was studied. After removing the ZLP, the spectrum image was linearly fitted with Gaussians centered at 1.46, 1.95, and 2.40 eV. The 2.40 eV peak is a well-known Au surface plasmon, whereas the remaining two are investigated in conjunction with modeling approaches. An RGB composite of the fit results can be seen in figure 1. Spectra extracted from the coloured regions can be seen in figure 2.

• Kjeldby, Snorre Braathen; Azarov, Alexander; Aarholt, Thomas; Prytz, Øystein & Vines, Lasse (2021). Defect-annealing in Si+-implanted β-Ga2O3.
• Nord, Magnus Kristofer; Aarholt, Thomas; O’Connell, Eoghan & Slater, Tom (2021). Atomap 0.3.0 release.
• Aarholt, Thomas (2020). Transmission Electron Microscopy for Advanced Functional Materials.
• Aarholt, Thomas (2020). International Webinar on Sample Preparation for TEM and Data Analysis.
• Aarholt, Thomas (2020). Imaging Nanomaterials with Transmission Electron Microscopy.
• Aarholt, Thomas (2019). Såpeboblens fysikk.
• Aarholt, Thomas (2019). Å se atomer.
• 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.
• Aarholt, Thomas; Frodason, Ymir Kalmann & Prytz, Øystein (2019). The impact of local relaxation on defect-complex STEM contrast.
• Hansen, Per-Anders Stensby; Zikmund, Tomas; Yu, Ting; Nitsche Kvalvik, Julie; Aarholt, Thomas & Prytz, Øystein [Show all 8 contributors for this article] (2018). Aromatic-fluoride nanocomposite materials by atomic layer deposition.
• Aarholt, Thomas; Sky, Thomas Neset; Nguyen, Phuong Dan & Prytz, Øystein (2018). Low-kV EELS band gapmeasurements on indium monolayer structures in ZnO.
• Aarholt, Thomas & Lobato, Ivan (2017). MULTEM Simulation Workshop.
• Aarholt, Thomas (2017). Searching for single-defects by GPU-accelerated STEM Simulation.
• Aarholt, Thomas (2017). Searching for single-defects by GPU-accelerated STEM simulation.
• Aarholt, Thomas (2017). Searching for single-defects by GPU-accelerated STEM simulation.
• Aarholt, Thomas (2017). Statistical analysis for noise reduction and phase separation in spectroscopy techniques.
• Aarholt, Thomas (2017). Smart Align - an acquisition tool for scanning microscopy.

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