Augustinas Galeckas

• Jagerová, Adéla; Malinský, Petr; Sofer, Zdeněk; Plutnarová, Iva; Vronka, Marek & Azarov, Alexander [Show all 8 contributors for this article] (2024). Evolution of Au nanoparticles in c-plane GaN under the heavy ion implantation and their optical properties. Journal of Alloys and Compounds. ISSN 0925-8388. 986. doi: 10.1016/j.jallcom.2024.174035.
• 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
• Hommedal, Ylva Knausgård; Frodason, Ymir Kalmann; Galeckas, Augustinas; Vines, Lasse & Johansen, Klaus Magnus H (2024). Broad luminescence from Zn acceptors in Zn doped β-Ga<inf>2</inf>O<inf>3</inf>. APL Materials. ISSN 2166-532X. 12(2). doi: 10.1063/5.0190156.
• Azarov, Alexander; Galeckas, Augustinas; Wendler, Elke; Monakhov, Eduard & Kuznetsov, Andrej (2024). Inverse dynamic defect annealing in ZnO. Applied Physics Letters. ISSN 0003-6951. 124(4). doi: 10.1063/5.0184669.
• Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; García Fernández, Javier; Haug, Kristian; Galeckas, Augustinas & Jensen, Ingvild Julie Thue [Show all 9 contributors for this article] (2023). Optical properties of ZnFe2O4 nanoparticles and Fe-decorated inversion domain boundaries in ZnO. Nanoscale Advances. 5(7), p. 2102–2110. doi: 10.1039/d2na00849a. Full text in Research Archive Show summary

  The maximum efficiency of solar cells utilizing a single layer for photovoltaic conversion is given by the single junction Shockley–Queisser limit. In tandem solar cells, a stack of materials with different band gaps contribute to the conversion, enabling tandem cells to exceed the single junction Shockley–Queisser limit. An intriguing variant of this approach is to embed semiconducting nanoparticles in a transparent conducting oxide (TCO) solar cell front contact. This alternative route would enhance the functionality of the TCO layer, allowing it to participate directly in photovoltaic conversion via photon absorption and charge carrier generation in the nanoparticles. Here, we demonstrate the functionalization of ZnO through incorporation of either ZnFe2O4 spinel nanoparticles (NPs) or inversion domain boundaries (IDBs) decorated by Fe. Diffuse reflectance spectroscopy and electron energy loss spectroscopy show that samples containing spinel particles and samples containing IDBs decorated by Fe both display enhanced absorption in the visible range at around 2.0 and 2.6 eV. This striking functional similarity was attributed to the local structural similarity around Fe-ions in spinel ZnFe2O4 and at Fe-decorated basal IDBs. Hence, functional properties of the ZnFe2O4 arise already for the two-dimensional basal IDBs, from which these planar defects behave like two-dimensional spinel-like inclusions in ZnO. Cathodoluminescence spectra reveal an increased luminescence around the band edge of spinel ZnFe2O4 when measuring on the spinel ZnFe2O4 NPs embedded in ZnO, whereas spectra from Fe-decorated IDBs could be deconvoluted into luminescence contributions from bulk ZnO and bulk ZnFe2O4.

• Macková, Anna; Jagerová, Adéla; Lalik, Ondrej; Mikšová, Romana; Poustka, David & Mistrík, Jan [Show all 12 contributors for this article] (2023). Combined Au/Ag nanoparticle creation in ZnO nanopillars by ion implantation for optical response modulation and photocatalysis. Applied Surface Science. ISSN 0169-4332. 610, p. 1–13. doi: 10.1016/j.apsusc.2022.155556. Full text in Research Archive Show summary

  ZnO nanopillars were implanted with Au-400 keV and Ag-252 keV ions with ion fluences from 1 × 1015 cm−2 to 1 × 1016 cm−2. We compared ZnO nanopillars solely implanted with Au-ions and dually-implanted with Au and Ag-ions. Rutherford Back-Scattering spectrometry (RBS) confirmed Ag and Au embedded in ZnO nanopillar layers in a reasonable agreement with theoretical calculations. A decreasing thickness of the ZnO nanopillar layer was evidenced with the increasing ion implantation fluences. Spectroscopic Ellipsometry (SE) showed a decrease of refractive index in the nanopillar parts with embedded Au, Ag-ions. XRD discovered vertical domain size decreasing with the proceeding radiation damage accumulated in ZnO nanopillars which effect was preferably ascribed to Au-ions. SE and diffuse reflectance spectroscopy (DRS) showed optical activity of the created nanoparticles at wavelength range 500 – 600 nm and 430 – 700 nm for the Au-implanted and Au, Ag-implanted ZnO nanopillars, respectively. Photoluminescence (PL) features linked to ZnO deep level emission appear substantially enhanced due to plasmonic interaction with metal nanoparticles created by Ag, Au-implantation. Photocatalytic activity seems to be more influenced by the nanoparticles presented in the layer rather than the surface morphology. Dual implantation with Ag, Au-ions enhanced optical activity to a larger extent without significant morphology deterioration as compared to the solely Au-ion implanted nanopillars.

• Azarov, Alexander; Galeckas, Augustinas; Ling, Francis Chi-Chung & Kuznetsov, Andrej (2022). Tuning defect-related optical bands by channeling implants in semiconductors. Journal of Physics D: Applied Physics. ISSN 0022-3727. 56(3). doi: 10.1088/1361-6463/aca778. 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
• Karsthof, Robert Michael; Frodason, Ymir Kalmann; Galeckas, Augustinas; Weiser, Philip Michael; Zviagin, Vitaly & Grundmann, Marius (2022). Light Absorption and Emission by Defects in Doped Nickel Oxide. Advanced Photonics Research. ISSN 2699-9293. 3(11). doi: 10.1002/adpr.202200138.
• Kang, Xiaolan; Reinertsen, Vilde Mari; Both, Kevin Gregor; Galeckas, Augustinas; Aarholt, Thomas & Prytz, Øystein [Show all 9 contributors for this article] (2022). Galvanic Restructuring of Exsolved Nanoparticles for Plasmonic and Electrocatalytic Energy Conversion. Small. ISSN 1613-6810. 18(29). doi: 10.1002/smll.202201106. Full text in Research Archive
• Macková, Anna; Malinský, Petr; Jagerová, Adéla; Mikšová, Romana; Lalik, Ondrej & Nekvindová, Pavla [Show all 14 contributors for this article] (2022). Energetic Au ion beam implantation of ZnO nanopillars for optical response modulation. Journal of Physics D: Applied Physics. ISSN 0022-3727. 55(215101). doi: 10.1088/1361-6463/ac5486. Full text in Research Archive
• Rauwel, Protima; Galeckas, Augustinas & Rauwel, Erwan (2021). Enhancing the UV emission in ZnO-CNT hybrid nanostructures via the surface plasmon resonance of Ag nanoparticles. Nanomaterials. ISSN 2079-4991. 11(2), p. 452–463. doi: 10.3390/nano11020452. Full text in Research Archive
• Kang, Xiaolan; Chaperman, Larissa; Galeckas, Augustinas; Ammar, Souad; Mammeri, Fayna & Norby, Truls [Show all 7 contributors for this article] (2021). Water Vapor Photoelectrolysis in a Solid-State Photoelectrochemical Cell with TiO2 Nanotubes Loaded with CdS and CdSe Nanoparticles. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(39), p. 46875–46885. doi: 10.1021/acsami.1c13047. Full text in Research Archive
• Aarseth, Bjørn Lupton; Granerød, Cecilie Skjold; Galeckas, Augustinas; Azarov, Alexander; Nguyen, Phuong Dan & Prytz, Øystein [Show all 7 contributors for this article] (2021). Formation and functionalization of Ge-nanoparticles in ZnO. Nanotechnology. ISSN 0957-4484. 32(50). doi: 10.1088/1361-6528/ac264a. Full text in Research Archive
• 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
• Olsen, Vegard Skiftestad; Øversjøen, Vetle; Gogova-Petrova, Daniela; Pecz, Bela; Galeckas, Augustinas & Borgersen, Jon Arthur [Show all 9 contributors for this article] (2021). ZnSnN2 in Real Space and k-Space: Lattice Constants, Dislocation Density, and Optical Band Gap. Advanced Optical Materials. ISSN 2195-1071. doi: 10.1002/adom.202100015.
• Kang, Xiaolan; Berberidou, Chrysanthi; Galeckas, Augustinas; Bazioti, Kalliopi; Sagstuen, Einar & Norby, Truls Eivind [Show all 8 contributors for this article] (2021). Visible Light Driven Photocatalytic Decolorization and Disinfection of Water Employing Reduced TiO2 Nanopowders. Catalysts. ISSN 2073-4344. 11(2). doi: 10.3390/catal11020228. Full text in Research Archive
• Kumar, Raj; Bergum, Kristin; Riise, Heine Nygard; Monakhov, Eduard; Galeckas, Augustinas & Svensson, Bengt Gunnar (2020). Impact of post annealing and hydrogen implantation on functional properties of Cu2O thin films for photovoltaic applications. Journal of Alloys and Compounds. ISSN 0925-8388. 825(5), p. 1–8. doi: 10.1016/j.jallcom.2020.153982. Full text in Research Archive
• Kjeldstad, Torunn; Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Jensen, Ingvild Julie Thue; Nilsen, Ola & Galeckas, Augustinas [Show all 7 contributors for this article] (2020). Selective etching of nanostructured a-Si:Al and its effect on porosity, Al gradient and surface oxidation. Thin Solid Films. ISSN 0040-6090. 702. doi: 10.1016/j.tsf.2020.137982. Full text in Research Archive Show summary

  Nanoporous amorphous silicon (a-Si) with <5 nm cylindrical pores have been fabricated by phase separation of aluminum (Al) and silicon, forming self-assembled Al nanowires (NWs), followed by subsequent removal of Al by wet etching. This work studies the removal process of the Al NWs when using the different etchants HCl, H3PO4, and H2SO4. Total reflectance measurements are used in combination with theoretical modeling to estimate the lateral gradient of Al concentration formed during the etching process. X-ray Photoelectron Spectroscopy is used to show that the choice of Al etching agent has implications for the surface states of the remaining a-Si matrix. We have found that H3PO4 is the most efficient etching agent, while HCl provides a less oxidized a-Si matrix in addition to the least reflective surface. By varying the etching agent, the degree of surface oxidation and shape of Al gradient throughout the film can be tuned.

• Azarov, Alexander; Galeckas, Augustinas; Venkatachalapathy, Vishnukanthan; Mei, Zengxia; Du, Xiaolong & Monakhov, Eduard [Show all 7 contributors for this article] (2020). Acceptor complex signatures in oxygen-rich ZnO thin films implanted with chlorine ions. Journal of Applied Physics. ISSN 0021-8979. 128. doi: 10.1063/5.0021089. Full text in Research Archive
• 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. ISSN 2331-7019. 14. doi: 10.1103/PhysRevApplied.14.054053. Full text in Research Archive
• 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.

• 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
• Azarov, Alexander; Galeckas, Augustinas; Mieszczyński, Cyprian; Hallen, Anders & Kuznetsov, Andrej (2020). Effects of annealing on photoluminescence and defect interplay in ZnO bombarded by heavy ions: Crucial role of the ion dose. Journal of Applied Physics. ISSN 0021-8979. 127. doi: 10.1063/1.5134011. Full text in Research Archive
• 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; Johansen, Klaus Magnus H; Galeckas, Augustinas; Vines, Lasse & Svensson, Bengt Gunnar (2020). Optical signatures of single ion tracks in ZnO. Nanoscale Advances. 2(2), p. 724–733. doi: 10.1039/C9NA00677J. Full text in Research Archive
• Rauwel, P; Galeckas, Augustinas & Rauwel, Erwan (2019). Time evolution of ZnO-CNT photoluminescence under variable ambient and temperature conditions. IOP Conference Series: Materials Science and Engineering. ISSN 1757-8981. 613(1). doi: 10.1088/1757-899X/613/1/012031. Full text in Research Archive
• 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. ISSN 2056-6387. 5(1), p. 1–9. doi: 10.1038/s41534-019-0227-y. Full text in Research Archive
• Rauwel, Protima; Galeckas, Augustinas; Ducroquet, Frédérique & Rauwel, Erwan (2019). Selective photocurrent generation in HfO2 and carbon nanotube hybrid nanocomposites under Ultra-Violet and visible photoexcitations. Materials Letters. ISSN 0167-577X. 246, p. 45–48. doi: 10.1016/j.matlet.2019.03.030.
• Frodason, Ymir Kalmann; Johansen, Klaus Magnus H; Galeckas, Augustinas & Vines, Lasse (2019). Broad luminescence from donor-complexed LiZn and NaZn acceptors in ZnO. Physical review B (PRB). ISSN 2469-9950. 100(18). doi: 10.1103/PhysRevB.100.184102. Full text in Research Archive
• Schifano, Ramon; Jakiela, R; Galeckas, Augustinas; Kopalko, K; Herklotz, Frank & Johansen, Klaus Magnus H [Show all 7 contributors for this article] (2019). Role of intrinsic and extrinsic defects in H implanted hydrothermally grown ZnO. Journal of Applied Physics. ISSN 0021-8979. 126(12). doi: 10.1063/1.5115597. Full text in Research Archive
• Olsen, Vegard Skiftestad; Baldissera, Gustavo; Zimmermann, Christian; Granerød, Cecilie Skjold; Bazioti, Kalliopi & Galeckas, Augustinas [Show all 11 contributors for this article] (2019). Evidence of defect band mechanism responsible for band gap evolution in (ZnO)1−x(GaN)x alloys. Physical review B (PRB). ISSN 2469-9950. 100(16). doi: 10.1103/PhysRevB.100.165201. Full text in Research Archive
• Kjeldstad, Torunn; Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Jensen, Ingvild Julie Thue; Monakhov, Eduard & Galeckas, Augustinas (2019). Surface effects and optical properties of self-assembled nanostructured a-Si:Al. Nanomaterials. ISSN 2079-4991. 9(8), p. 1–12. doi: 10.3390/nano9081106. Full text in Research Archive Show summary

  We present a study of the surface effects and optical properties of the self-assembled nanostructures comprised of vertically aligned 5 nm-diameter Al nanowires embedded in an amorphous Si matrix (a-Si:Al). The controlled (partial) removal of Al nanowires in a selective etching process yielded nanoporous a-Si media with a variable effective surface area. Different spectroscopy techniques, such as X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometry and photoluminescence (PL), have been combined to investigate the impact of such nanostructuring on optical absorption and emission properties. We also examine long-term exposure to air ambient and show that increasing level of surface oxidation determines the oxide defect-related nature of the dominant PL emission from the nanoporous structures. The role of bulk, nanosize and surface effects in optical properties has been separated and quantified, providing a better understanding of the potential of such nanoporous a-Si:Al structures for future device developments

• Ayedh, Hussein Mohammed Hussein; Grigorev, Aleksei; Galeckas, Augustinas; Svensson, Bengt Gunnar & Monakhov, Eduard (2019). Annealing Kinetics of the Interstitial Carbon–Dioxygen Complex in Silicon. Physica Status Solidi (a) applications and materials science. ISSN 1862-6300. 216(14), p. 1–5. doi: 10.1002/pssa.201800986.
• Kjeldstad, Torunn; Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Azarov, Alexander; Monakhov, Eduard & Galeckas, Augustinas (2019). Monitoring selective etching of self-assembled nanostructured a-Si:Al films. Nanotechnology. ISSN 0957-4484. 30(13), p. 1–5. doi: 10.1088/1361-6528/aafb86. Full text in Research Archive
• Almeida Carvalho, Patricia; Thøgersen, Annett; Ma, Quanbao; Wright, Daniel Nilsen; Diplas, Spyridon & Galeckas, Augustinas [Show all 12 contributors for this article] (2018). Boron-doping of cubic SiC for intermediate band solar cells: a scanning transmission electron microscopy study. SciPost Physics. ISSN 2542-4653. 5(3). doi: 10.21468/SciPostPhys.5.3.021.
• Ayedh, Hussein Mohammed Hussein; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Hassan, Jawad U; Bergman, J. P. & Nipoti, Roberta [Show all 8 contributors for this article] (2018). Controlling the carbon vacancy in 4H-SiC by thermal processing. ECS Transactions. ISSN 1938-5862. 86(12), p. 91–97. doi: 10.1149/08612.0091ecst.
• Venkatachalapathy, Vishnukanthan; Galeckas, Augustinas; Azarov, Alexander; Vines, Lasse & Kuznetsov, Andrej (2018). Phase stability and strain accumulation in CdO as a function of Cd/O supply during MOVPE synthesis. Superlattices and Microstructures. ISSN 0749-6036. 120, p. 569–577. doi: 10.1016/j.spmi.2018.06.017.
• Galeckas, Augustinas; Almeida Carvalho, Patricia; Ma, Quanbao; Azarov, Alexander; Hovden, Sigurd Slettemark & Thøgersen, Annett [Show all 13 contributors for this article] (2018). Optical and microstructural investigation of heavy B-doping effects in sublimation-grown 3C-SiC. Materials Science Forum. ISSN 0255-5476. 924, p. 221–224. doi: 10.4028/www.scientific.net/MSF.924.221. Show summary

  In this work, a complementary microstructural and optical approach is used to define processing conditions favorable for the formation of deep boron-related acceptor centers that may provide a pathway for achieving an intermediate band behavior in highly B-doped 3C-SiC. The crystallinity, boron solubility and precipitation mechanisms in sublimation-grown 3C-SiC crystals implanted to 1-3 at.% B concentrations were investigated by STEM. The revealed defect formation and boron precipitation trends upon thermal treatment in the range 1100-2000°C have been cross-correlated with the optical characterization results provided by imaging PL spectroscopy. We discuss optical activity of the implanted B ions in terms of both shallow acceptors and deep D-centers, a complex formed by a boron atom and a carbon vacancy, and associate the observed spectral developments upon annealing with the strong temperature dependence of the D-center formation efficiency, which is further enhanced by the presence of implantation-induced defects.

• Bergum, Kristin; Riise, Heine Nygard; Gorantla, Sandeep Madhukar; Lindberg, Per; Jensen, Ingvild Julie Thue & Gunnæs, Anette Eleonora [Show all 10 contributors for this article] (2018). Improving carrier transport in Cu2O thin films by rapid thermal annealing. Journal of Physics: Condensed Matter. ISSN 0953-8984. 30(7). doi: 10.1088/1361-648X/aaa5f4.
• Montero, José ; Galeckas, Augustinas & Karazhanov, Smagul (2018). Photoluminescence Properties of Photochromic Yttrium Hydride Films Containing Oxygen. Physica status solidi (b). ISSN 0370-1972. 255(8). doi: 10.1002/pssb.201800139. Full text in Research Archive
• Granerød, Cecilie Skjold; Galeckas, Augustinas; Johansen, Klaus Magnus H; Vines, Lasse & Prytz, Øystein (2018). The temperature-dependency of the optical band gap of ZnO measured by electron energy-loss spectroscopy in a scanning transmission electron microscope. Journal of Applied Physics. ISSN 0021-8979. 123(14), p. 1–6. doi: 10.1063/1.5023316. Full text in Research Archive
• Rauwel, Erwan; Galeckas, Augustinas; Soares, M Rosario & Rauwel, Protima (2017). Influence of the Interface on the Photoluminescence Properties in ZnO Carbon-Based Nanohybrids. Journal of Physical Chemistry C. ISSN 1932-7447. 121(27), p. 14879–14887. doi: 10.1021/acs.jpcc.7b03070.
• Ma, Quanbao; Carvalho, Patricia; Galeckas, Augustinas; Azarov, Alexander; Hovden, Sigurd Slettemark & Thøgersen, Annett [Show all 13 contributors for this article] (2017). Characterization of B-implanted 3C-SiC for intermediate band solar cells. Materials Science Forum. ISSN 0255-5476. 897, p. 299–302. doi: 10.4028/www.scientific.net/MSF.897.299. Show summary

  Sublimation-grown 3C-SiC crystals were implanted with B ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 1.3×1017 atoms/cm2 in order to form intermediate band (IB) in 3C-SiC. The samples were then annealed at 1400 °C for 60 min. An anomalous area in the center was observed in the PL emission pattern. The SIMS analysis indicated that the B concentration was the same both within and outside the anomalous area. The buried boron box-like concentration profile can reach ~3×1021 cm-3 in the plateau region. In the anomalous area a broad emission band (possible IB) emerges at around ~1.7-1.8 eV, which may be associated with B-precipitates having a sufficiently high density. Sublimation-grown 3C-SiC crystals were implanted with B ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 1.3×1017 atoms/cm2 in order to form intermediate band (IB) in 3C-SiC. The samples were then annealed at 1400 °C for 60 min. An anomalous area in the center was observed in the PL emission pattern. The SIMS analysis indicated that the B concentration was the same both within and outside the anomalous area. The buried boron box-like concentration profile can reach ~3×1021 cm-3 in the plateau region. In the anomalous area a broad emission band (possible IB) emerges at around ~1.7-1.8 eV, which may be associated with B-precipitates having a sufficiently high density.

• Azarov, Alexander; Galeckas, Augustinas; Wendler, Elke; Ellingsen, Josef Gert Åsheim; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Normal and reverse defect annealing in ion implanted II-VI oxide semiconductors. Journal of Applied Physics. ISSN 0021-8979. 122. doi: 10.1063/1.4997847.
• Galeckas, Augustinas; Ayedh, Hussein Mohammed Hussein; Bergman, J. Peder & Svensson, Bengt Gunnar (2017). Depth-resolved Carrier Lifetime Measurements in 4H-SiC Epilayers Monitoring Carbon Vacancy Elimination. Materials Science Forum. ISSN 0255-5476. 897, p. 258–261. doi: 10.4028/www.scientific.net/MSF.897.258.
• Rauwel, Protima; Galeckas, Augustinas; Salumaa, Martin; Aasna, Andres; Ducroquet, Frédérique & Rauwel, Erwan Yann (2017). Investigations on new carbon-based nanohybrids combining carbon nanotubes, HfO2 and ZnO nanoparticles. IOP Conference Series: Materials Science and Engineering. ISSN 1757-8981. 175(1). doi: 10.1088/1757-899X/175/1/012064.
• Kjeldstad, Torunn; Thøgersen, Annett; Nilsen, Ola; Monakhov, Edouard & Galeckas, Augustinas (2017). Controllable template approach for ZnO nanowire growth. Physica Status Solidi (a) applications and materials science. ISSN 1862-6300. 214(2), p. 1–6. doi: 10.1002/pssa.201600480. Show summary

  Anodic aluminum oxide (AAO) is an optically transparent material with uniform hexagonal pores, which has widely been used as a template for nanowire growth. This study examines the potential of utilizing commercially available AAO to fabricate sub-10 nm ZnO nanowires by atomic layer deposition. The pore diameter of the AAO framework is reduced by controlled deposition of . Subsequently, ZnO is deposited and ZnO nanowires are obtained. The analysis of structural and optical properties shows that the nanowires are polycrystalline, and exhibit a pronounced near band edge emission. Photoluminescence (PL) measurements are performed to monitor the effect of additional coating with and ZnO, on the optical stability of the AAO. The measurements indicate that the PL is highly influenced by the adsorption and desorption of species from the ambient at the surface. ALD deposition of a thin layer reduces considerably the effect of ambient atmosphere. The layer of facilitates PL characterization of very thin ZnO nanowires.

• Rauwel, Protima; Galeckas, Augustinas; Salumaa, Martin; Ducroquet, Frédérique & Rauwel, Erwan (2016). Photocurrent generation in carbon nanotube/cubic-phase HfO2 nanoparticle hybrid nanocomposites. Beilstein Journal of Nanotechnology. ISSN 2190-4286. 7, p. 1075–1085. doi: 10.3762/bjnano.7.101.
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Mei, Zengxia; Liu, Lishu; Du, Xiaolong & Galeckas, Augustinas [Show all 9 contributors for this article] (2016). Self-diffusion measurements in isotopic heterostructures of undoped and in situ doped ZnO: Zinc vacancy energetics. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 94. doi: 10.1103/PhysRevB.94.195208.

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• 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 ​.
• Garcia Fernandez, Javier; Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; Haug, Kristian; Galeckas, Augustinas & Jensen, Ingvild Julie Thue [Show all 9 contributors for this article] (2023). Optical properties and structure relationship in ZnO:Fe with inversion domain boundaries and ZnFe2O4/ZnO heterostructures.
• 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.
• 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.
• 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.
• Kang, Xiaolan; Reinertsen, Vilde Mari; Both, Kevin Gregor; Galeckas, Augustinas; Aarholt, Thomas & Prytz, Øystein [Show all 9 contributors for this article] (2022). Exsolved nanoparticles, galvanically restructured for tunable photo-electrocatalytic energy conversion.
• Kang, Xiaolan; Chaperman, Larissa; Galeckas, Augustinas; Ammar-Merah, Souad; Mammeri, Fayna & Norby, Truls [Show all 7 contributors for this article] (2022). Water Vapor Photoelectrolysis in an All Solid-State Photoelectrochemical Cell .
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Vines, Lasse (2022). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• Galeckas, Augustinas; Karsthof, Robert Michael; Gana, Kingsly; Kok, Angela; Bathen, Marianne Etzelmüller & Vines, Lasse [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. 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.

• Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; Garcia Fernandez, Javier; Haug, Kristian; Galeckas, Augustinas & Jensen, Ingvild Julie Thue [Show all 9 contributors for this article] (2022). Optical properties of Fe-decorated inversion domain boundaries and embedded spinel zinc ferrite nanoparticles in zinc oxide.
• Garcia Fernandez, Javier; Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; Haug, Kristian; Galeckas, Augustinas & Jensen, Ingvild Julie Thue [Show all 9 contributors for this article] (2022). Structural and optical investigation of Fe-ZnO nanoarchitectures: from inversion domain boundaries to ZnO/ZnFe2O4 heterostructure.
• 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
• Kang, Xiaolan; Reinertsen, Vilde Mari; Both, Kevin Gregor; Galeckas, Augustinas; Aarholt, Thomas & Prytz, Øystein [Show all 9 contributors for this article] (2022). Galvanic Restructuring of Exsolved Nanoparticles for Plasmonic and Electrocatalytic Energy Conversion (Small 29/2022 Inside back cover feature). Small. ISSN 1613-6810. 18(29).
• Kang, Xiaolan; Reinertsen, Vilde Mari; Both, Kevin Gregor; Galeckas, Augustinas; Aarholt, Thomas & Prytz, Øystein [Show all 9 contributors for this article] (2022). Galvanic restructuring of exsolved nanoparticles for plasmonic and electrocatalytic energy conversion .
• 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.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas & Vines, Lasse (2021). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Enga, Marius & Vines, Lasse (2021). Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC.
• Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; Haug, Kristian; Galeckas, Augustinas; Jensen, Ingvild Julie Thue & Thøgersen, Annett [Show all 8 contributors for this article] (2021). EELS and SEM-CL investigations of ZnFe2O4 nanoparticles and iron-decorated inversion domain boundaries in bulk ZnO.
• Azarov, Alexander; Galeckas, Augustinas; Mieszczyński, Cyprian; Hallen, Anders & Kuznetsov, Andrej (2019). Effects of annealing on photoluminescence and defect interplay in ZnO bombarded with heavy ions: crucial role of the ion dose.
• Frodason, Ymir Kalmann; Johansen, Klaus Magnus H; Galeckas, Augustinas & Vines, Lasse (2019). Optical properties of donor-complexed Li_Zn in ZnO .
• Vasquez, Geraldo Cristian; Bazioti, Kalliopi; Galeckas, Augustinas; Johansen, Klaus Magnus H; Granerød, Cecilie Skjold & Nguyen, Phuong Dan [Show all 8 contributors for this article] (2019). Luminescent properties of Zn2GeO4 nanoparticles embedded in ZnO.
• Vasquez, Geraldo Cristian; Galeckas, Augustinas; Johansen, Klaus Magnus H; Vines, Lasse & Svensson, Bengt Gunnar (2019). Optical and electrical properties of single ion-tracks in crystalline SiC.
• 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.
• 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 emission intensity modulation of the silicon vacancy in 4H-SiC.
• 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. 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.

• Ayedh, Hussein Mohammed Hussein; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Ul Hassan, Jawad; Bergman, J. P. & Nipoti, Roberta [Show all 8 contributors for this article] (2018). Controlling the Carbon Vacancy in 4H-SiC By Thermal Processing.
• Venkatachalapathy, Vishnukanthan; Vajeeston, Ponniah; Galeckas, Augustinas; Vines, Lasse & Kuznetsov, Andrej (2018). Direct and indirect bandgaps of Cadmium Oxide.
• Vasquez, Geraldo Cristian; Johansen, Klaus Magnus H; Galeckas, Augustinas; Vines, Lasse; Svensson, Bengt Gunnar & Maestre, David (2018). Single ion-tracks in crystalline ZnO and their influence on the near band edge luminescence.
• Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Frodason, Ymir Kalmann; Vines, Lasse & Svensson, Bengt Gunnar (2018). Tuning silicon vacancy formation in 4H-SiC via proton irradiation for quantum technology.
• Kjeldstad, Torunn; Thøgersen, Annett; Galeckas, Augustinas; Monakhov, Eduard; Stange, Marit Synnøve Sæverud & Nilsen, Ola (2018). Aluminum nanowires in amorphous silicon.
• Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Galeckas, Augustinas; Nilsen, Ola & Monakhov, Eduard (2018). Aluminum nanowires in amorphous silicon.
• Bathen, Marianne Etzelmüller; Vines, Lasse; Galeckas, Augustinas; Frodason, Ymir Kalmann & Svensson, Bengt Gunnar (2018). Correlating charge state transitions of the Si vacancy to the S1/S2 peaks in DLTS spectra of n-type 4H-SiC.
• Bathen, Marianne Etzelmüller; Vines, Lasse; Galeckas, Augustinas; Frodason, Ymir Kalmann & Svensson, Bengt Gunnar (2018). Charge state transitions of the silicon vacancy in 4H-SiC: Combined DLTS, PL and DFT study.
• Ayedh, Hussein Mohammed Hussein; Azarov, Alexander; Galeckas, Augustinas; Svensson, Bengt Gunnar & Monakhov, Edouard (2017). DLTS study of the interstitial carbon–oxygen complex in proton irradiated p-type Si.
• Bergum, Kristin; Borgersen, Jon Arthur; Ellingsen, Josef Gert Åsheim; Frodason, Ymir Kalmann; Galeckas, Augustinas & Ingebrigtsen, Mads Eide [Show all 8 contributors for this article] (2017). Omvisning MiNaLab.
• Frodason, Ymir Kalmann; Bergum, Kristin; Sky, Thomas Neset; Ingebrigtsen, Mads Eide; Borgersen, Jon & Ellingsen, Josef Gert Åsheim [Show all 8 contributors for this article] (2017). MiNa-Lab tour highlighting LENS activities.
• Nyborg, Martin; Lindberg, Per; Svensson, Bengt Gunnar; Monakhov, Edouard & Galeckas, Augustinas (2017). DC Magnetron Sputter Deposition of CuxO Thin Films The Effect of Target Power and O2 Flow. Show summary

  In this study, we report on the effect of target power and O2 flow on DC magnetron sputter deposited CuxO thin films. Target power (Ptar) and oxygen flow (QO2) have been varied in the 80 - 100 W and 12-19 sccm range while keeping all other parameters constant.

• Kjeldstad, Torunn; Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Galeckas, Augustinas & Monakhov, Edouard (2017). Self-assembled aluminium nanowires in silicon.
• Kjeldstad, Torunn; Galeckas, Augustinas; Nilsen, Ola; Azarov, Alexander; Stange, Marit Synnøve Sæverud & Diplas, Spyridon [Show all 7 contributors for this article] (2017). Self-assembly of Al-nanowires in silicon.
• Kjeldstad, Torunn; Thøgersen, Annett; Monakhov, Edouard & Galeckas, Augustinas (2017). Investigation of mesoporous aSi:H with embedded aluminium nanoparticles.
• Kjeldstad, Torunn; Thøgersen, Annett; Monakhov, Edouard & Galeckas, Augustinas (2017). Aluminium nanoparticles embedded in mesoporous aSi:H.
• Thøgersen, Annett; Kjeldstad, Torunn; Jensen, Ingvild Julie Thue; Muntingh, Agnar Georg Peder; Stange, Marit Synnøve Sæverud & Ulyashin, Alexander [Show all 9 contributors for this article] (2017). Plasmonic properties of aluminium nanowires in amorphous silicon and inverted silicon nanowires.
• Granerød, Cecilie Skjold; Galeckas, Augustinas; Vines, Lasse; Johansen, Klaus Magnus H & Prytz, Øystein (2017). Temperature-dependency of the ZnO band gap measured by STEM-EELS.
• Granerød, Cecilie Skjold; Galeckas, Augustinas; Johansen, Klaus Magnus H; Vines, Lasse & Prytz, Øystein (2017). The temperature-dependency of the ZnO bandgap studied by STEM-EELS.
• Thøgersen, Annett; Kjeldstad, Torunn; Jensen, Ingvild Julie Thue; Stange, Marit Synnøve Sæverud; Ulyashin, Alexander & Galeckas, Augustinas [Show all 9 contributors for this article] (2017). Growing and characterizing self-organizing aluminium nanowires in amorphous silicon.
• Venkatachalapathy, Vishnukanthan; Bakke, Marius Mordal; Galeckas, Augustinas; Vines, Lasse & Kuznetsov, Andrej (2016). Investigation of polar and non-polar Zn(Mg,Cd)O-based Multiple Quantum Wells.
• Venkatachalapathy, Vishnukanthan; Galeckas, Augustinas; Azarov, Alexander & Kuznetsov, Andrej (2016). Structural and optical properties of cubic Cd1-xZnxO.
• Ma, Quanbao; Carvalho, Patricia; Galeckas, Augustinas; Azarov, Alexander; Hovden, Sigurd & Thøgersen, Annett [Show all 13 contributors for this article] (2016). Characterization of B-implanted 3C-SiC for intermediate band solar cells .
• Kjeldstad, Torunn; Galeckas, Augustinas; Nilsen, Ola; Azarov, Alexander; Stange, Marit Synnøve Sæverud & Diplas, Spyridon [Show all 7 contributors for this article] (2016). A new silicon nanostructure.
• Kjeldstad, Torunn; Galeckas, Augustinas; Monakhov, Edouard; Nilsen, Ola & Thøgersen, Annett (2016). Controllable template approach for ZnO nanowire growth.

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