aazarov

• Whitlow, Harry James; Kuznetsov, Andrej; Azarov, Alexander; Nagy, Gyula; Frost, Robert J.W. & Henderson, Nicholas [Show all 17 contributors for this article] (2024). Dynamic Analysis of major elements in biological tissue validating quantification of trace life elements in MeV ion beam microscopy. Nuclear Instruments and Methods in Physics Reseach B. ISSN 0168-583X. 554. doi: 10.1016/j.nimb.2024.165411.
• Chen, Xingqian; Li, Haozhen; Chen, Wei; Mei, Zengxia; Azarov, Alexander & Kuznetsov, Andrej [Show all 7 contributors for this article] (2024). Interstitial Doping of SnO<inf>2</inf> Film with Li for Indium-Free Transparent Conductor. Chinese Physics Letters. ISSN 0256-307X. 41(3). doi: 10.1088/0256-307X/41/3/037305.
• García Fernández, Javier; Kjeldby, S.B.; Zeng, L.J.; Azarov, Alexander; Pokle, Anuj & Nguyen, Phuong Dan [Show all 10 contributors for this article] (2024). In situ atomic-resolution study of transformations in double polymorph ?/ß-Ga<inf>2</inf>O<inf>3</inf> structures. Materials Advances. ISSN 2633-5409. doi: 10.1039/d3ma01011b.
• 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.
• 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.
• Polyakov, Alexander Y.; Vasilev, Anton A.; Kochkova, Anastasiia I.; Shchemerov, Ivan V.; Yakimov, Eugene B. & Miakonkikh, Andrej V. [Show all 17 contributors for this article] (2024). Proton damage effects in double polymorph γ/β-Ga<inf>2</inf>O<inf>3</inf> diodes. Journal of Materials Chemistry C. ISSN 2050-7526. 12, p. 1020–1029. doi: 10.1039/d3tc04171a.
• Polyakov, Alexander Y.; Yakimov, Eugene B.; Nikolaev, Vladimir I.; Pechnikov, Alexei I.; Miakonkikh, Andrej V. & Azarov, Alexander [Show all 12 contributors for this article] (2023). Impact of Hydrogen Plasma on Electrical Properties and Deep Trap Spectra in Ga2O3 Polymorphs. Crystals. ISSN 2073-4352. 13(9), p. 1–25. doi: 10.3390/cryst13091400. Full text in Research Archive Show summary

  In this study, the results of hydrogen plasma treatments of β-Ga2O3, α-Ga2O3, κ-Ga2O3 and γ-Ga2O3 polymorphs are analyzed. For all polymorphs, the results strongly suggest an interplay between donor-like hydrogen configurations and acceptor complexes formed by hydrogen with gallium vacancies. A strong anisotropy of hydrogen plasma effects in the most thermodynamically stable β-Ga2O3 are explained by its low-symmetry monoclinic crystal structure. For the metastable, α-, κ- and γ-polymorphs, it is shown that the net result of hydrogenation is often a strong increase in the density of centers supplying electrons in the near-surface regions. These centers are responsible for prominent, persistent photocapacitance and photocurrent effects.

• Azarov, Alexander; García Fernández, Javier; Zhao, Junlei; Djurabekova, Flyura; He, Huan & He, Ru [Show all 13 contributors for this article] (2023). Universal radiation tolerant semiconductor. Nature Communications. ISSN 2041-1723. 14, p. 1–8. doi: 10.1038/s41467-023-40588-0. Full text in Research Archive
• Zaborowska, A.; Kurpaska, L.; Wyszkowska, E.; Azarov, Alexander; Turek, M. & Kosińska, A. [Show all 8 contributors for this article] (2023). High versus low energy ion irradiation impact on functional properties of PLD-grown alumina coatings. Nuclear Instruments and Methods in Physics Reseach B. ISSN 0168-583X. 540, p. 24–29. doi: 10.1016/j.nimb.2023.03.027. Full text in Research Archive
• Wyszkowska, E.; Mieszczynski, C.; Kurpaska, Ł.; Azarov, Alexander; Chromiński, W. & Jóźwik, I. [Show all 13 contributors for this article] (2023). The Fe addition as an effective treatment for improving the radiation resistance of fcc NixFe1-x single-crystal alloys. Journal of Nuclear Materials. ISSN 0022-3115. 584, p. 1–12. doi: 10.1016/j.jnucmat.2023.154565. Full text in Research Archive Show summary

  In this work, five different compositions of fcc Ni and NixFe1-x single crystal alloys namely Ni, Ni0.88Fe0.12, Ni0.77Fe0.23, Ni0.62Fe0.38, Ni0.38Fe0.62 were irradiated by 1.5 MeV 58Ni ions at room temperature in a wide fluence range (4 × 1013 to 4 × 1015 ions/cm2). The role of Fe addition on the radiation resistance of the NixFe1-x single crystals was studied by transmission electron microscopy (TEM), ion channeling technique (RBS/C) and nanoindentation techniques. The Multi-Step Damage Accumulation analysis revealed the cross-sections for damage formation significantly decreases for Ni0.38Fe0.62 and Ni0.62Fe0.38 as compared to that in pure Ni single crystal, which is consistent with RBS/C and TEM results. The results of nanoindentation show that Ni0.62Fe0.38 alloy possesses the highest hardness (2.96 GPa) among the other compositions in a pristine state. To interpret this result, hybrid Monte Carlo/ Molecular dynamics simulations were used to check the presence of the ordered crystal phase structure for NixFe1-x binary alloys. The simulation results have shown that depending on the iron content, we deal with different amounts of FeNi3 (L12) phase. This result revealed that in Ni0.62Fe0.38 alloy, nanoprecipitate FeNi3 (L12) phase (around 20%) is formed inside the disordered matrix, which could be one of the main reasons for the high hardness of this alloy before irradiation. Additionally, we have found adding iron reduced the number and size of the defects (as a result of ion irradiation) in NixFe1-x because the Fe element is more stable than Ni, which results from the electron configuration of both elements in the excited state. Therefore, the more iron in the material, the fewer defects are created.

• Mieszczynski, Cyprian; Jozwik, Przemyslaw; Skrobas, Kazimierz; Stefanska-Skrobas, Kamila; Ratajczak, Renata & Jagielski, Jacek [Show all 11 contributors for this article] (2023). Combining MD-LAMMPS and MC-McChasy2 codes for dislocation simulations of Ni single crystal structure. Nuclear Instruments and Methods in Physics Reseach B. ISSN 0168-583X. 540, p. 38–44. doi: 10.1016/j.nimb.2023.04.010. Full text in Research Archive
• Polyakov, A.Y.; Kuznetsov, Andrej; Azarov, Alexander; Miakonkikh, A.V.; Chernykh, A.V. & Vasilev, A.A. [Show all 10 contributors for this article] (2023). The effects of hydrogenation on the properties of heavy ion irradiated β-Ga2O3. Journal of materials science. Materials in electronics. ISSN 0957-4522. 34(15). doi: 10.1007/s10854-023-10628-y. Full text in Research Archive
• Azarov, Alexander; Park, Ji-Hyeon; Jeon, Dae-Woo & Kuznetsov, Andrej (2023). High mobility of intrinsic defects in α-Ga2O3. Applied Physics Letters. ISSN 0003-6951. 122(18), p. 182104-1–182104-4. doi: 10.1063/5.0149870. Full text in Research Archive Show summary

  Migration properties of the intrinsic defects were investigated in α-Ga2O3 by controllable introduction of the lattice disorder with ion irradiation and monitoring its evolution as a function of ion dose, flux, and temperature. Already the dose dependence acquired at room temperature suggested prominently high mobility of intrinsic defects in α-Ga2O3, since we observed two distinct disordered regions—near the surface and in the bulk—instead of a Gaussian shape following the ballistic defects production process. Moreover, the disorder accumulation has shown to be highly sensitive to the variation of the ion flux and temperature, known in the literature as the dose-rate effect. Therefore, by monitoring the process as a function of the flux and temperature, we observed such dose-rate effect in α-Ga2O3 with an activation energy of 0.33 ± 0.04 eV, which we attributed to the migration barrier of the intrinsic defects in the Ga sublattice, from where we collected the experimental data. By setting these results in the context of the theoretical data available in the literature, we argued that this energy may be attributed to the migration activation of the Ga self-interstitials in α-Ga2O3.

• Polyakov, A.Y.; Kochkova, A.I.; Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Miakonkikh, A.V. & Vasilev, A.A. [Show all 11 contributors for this article] (2023). Tuning electrical properties in Ga2O3 polymorphs induced with ion beams. Journal of Applied Physics. ISSN 0021-8979. 133(9), p. 095701-1–095701-9. doi: 10.1063/5.0133181. Full text in Research Archive Show summary

  Ion beam fabrication of metastable polymorphs of Ga2O3, assisted by the controllable accumulation of the disorder in the lattice, is an interesting alternative to conventional deposition techniques. However, the adjustability of the electrical properties in such films is unexplored. In this work, we investigated two strategies for tuning the electron concentration in the ion beam created metastable κ-polymorph: adding silicon donors by ion implantation and adding hydrogen via plasma treatments. Importantly, all heat treatments were limited to ≤600 °C, set by the thermal stability of the ion beam fabricated polymorph. Under these conditions, silicon doping did not change the high resistive state caused by the iron acceptors in the initial wafer and residual defects accumulated upon the implants. Conversely, treating samples in a hydrogen plasma converted the ion beam fabricated κ-polymorph to n-type, with a net donor density in the low 1012 cm−3 range and dominating deep traps near 0.6 eV below the conduction band. The mechanism explaining this n-type conductivity change may be due to hydrogen forming shallow donor complexes with gallium vacancies and/or possibly passivating a fraction of the iron acceptors responsible for the high resistivity in the initial wafers.

• Arslan, H.; Aulika, I.; Sarakovskis, A.; Bikse, L.; Zubkins, M. & Azarov, Alexander [Show all 8 contributors for this article] (2023). Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics. Vacuum. ISSN 0042-207X. 211, p. 1–11. doi: 10.1016/j.vacuum.2023.111942. Full text in Research Archive
• Nowak, M.; Mulewska, K.; Azarov, Alexander; Kurpaska, L. & Ustrzycka, A. (2023). A peridynamic elasto-plastic damage model for ion-irradiated materials. International Journal of Mechanical Sciences. ISSN 0020-7403. 237, p. 1–19. doi: 10.1016/j.ijmecsci.2022.107806. Full text in Research Archive
• Wyszkowska, E.; Mieszczynski, C.; Kurpaska, Ł.; Azarov, Alexander; Jóźwik, I. & Kosińska, A. [Show all 11 contributors for this article] (2023). Tuning heterogeneous ion-radiation damage by composition in NixFe1−x binary single crystals. Nanoscale. ISSN 2040-3364. 15, p. 4870–4881. doi: 10.1039/d2nr06178c. Show summary

  Radiation-induced heterogeneous damage is the single largest source of failures seen in structural components in nuclear power reactors. Single crystal materials without grain boundaries, show considerable promise for overcoming this problem. In this work, such heterogeneous damage was further overcome in NixFe1−x single crystal alloys via a simple strategy of fine-tuning the composition. [001] NixFe1−x (x = 0, 0.38 and 0.62 at%) single crystals prepared using the Bridgman method were irradiated over a wide fluence range (4 × 1013 to 4 × 1015 ions per cm2). The irradiation-induced defect evolution was studied using Rutherford backscattering/channeling spectrometry, Monte Carlo simulations, transmission electron microscopy and nanoindentation. The results indicate an increased radiation tolerance of Ni0.38Fe0.62 compared to pure Ni and Ni0.62Fe0.38. The structural analysis performed by transmission electron microscopy revealed that defects tend to agglomerate at one place in Ni and Ni0.62Fe0.38, while in Ni0.38Fe0.62 no defect accumulation zone (characteristic damage peak) has been captured either at low or high fluence. Moreover, we found that the hardness change with the increase of Fe content is due to different arrangements of Fe atoms in the crystal structure, which influences the obtained mechanical properties of NixFe1−x in the pristine state and after ion implantation.

• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Lee, In-Hwan & Kuznetsov, Andrej (2023). Thermal versus radiation-assisted defect annealing in β-Ga2O3. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. ISSN 0734-2101. 41(2). doi: 10.1116/6.0002388. Full text in Research Archive
• 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
• Adeojo, Samuel; Malherbe, Johan; Azarov, Alexander; Odutemowo, Opeyemi; Njoroge, Eric & Abdelbagi, Hesham [Show all 8 contributors for this article] (2022). Effects of implantation temperature and annealing on structural evolution and migration of Se into glassy carbon. Solid State Sciences. ISSN 1293-2558. 129. doi: 10.1016/j.solidstatesciences.2022.106914. Full text in Research Archive
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Karaseov, Platon; Titov, Andrei; Karabeshkin, Konstantin & Struchkov, Andrei [Show all 7 contributors for this article] (2022). Interplay of the disorder and strain in gallium oxide. Scientific Reports. ISSN 2045-2322. 12(1). doi: 10.1038/s41598-022-19191-8. Full text in Research Archive
• Kjeldby, Snorre Braathen; Azarov, Alexander; Nguyen, Phuong Dan; Venkatachalapathy, Vishnukanthan; Mikšová, R. & MacKová, A. [Show all 9 contributors for this article] (2022). Radiation-induced defect accumulation and annealing in Si-implanted gallium oxide. Journal of Applied Physics. ISSN 0021-8979. 131(12). doi: 10.1063/5.0083858. Full text in Research Archive
• Titov, A.I.; Karabeshkin, K.V.; Struchkov, A.I.; Nikolaev, V.I.; Azarov, Alexander & Gogova, D.S. [Show all 7 contributors for this article] (2022). Comparative study of radiation tolerance of GaN and Ga2O3 polymorphs. Vacuum. ISSN 0042-207X. 200. doi: 10.1016/j.vacuum.2022.111005. 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
• Titov, A.I.; Karabeshkin, K.V.; Struchkov, A.I.; Karaseov, P.A. & Azarov, Alexander (2022). Radiation tolerance of GaN: The balance between radiation-stimulated defect annealing and defect stabilization by implanted atoms. Journal of Physics D: Applied Physics. ISSN 0022-3727. 55(17). doi: 10.1088/1361-6463/ac4a38. Full text in Research Archive
• Azarov, Alexander; Bazioti, Kalliopi; Venkatachalapathy, Vishnukanthan; Ponniah, Vajeeston; Monakhov, Eduard & Kuznetsov, Andrej (2022). Disorder-Induced Ordering in Gallium Oxide Polymorphs. Physical Review Letters. ISSN 0031-9007. 128(1). doi: 10.1103/PhysRevLett.128.015704. Full text in Research Archive
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Vines, Lasse; Monakhov, Eduard; Lee, In-Hwan & Kuznetsov, Andrej (2021). Activation energy of silicon diffusion in gallium oxide: Roles of the mediating defects charge states and phase modification. Applied Physics Letters. ISSN 0003-6951. 119(18). doi: 10.1063/5.0070045. Full text in Research Archive
• Nyborg, Martin; Azarov, Alexander; Bergum, Kristin & Monakhov, Eduard (2021). Deposition and characterization of lithium doped direct current magnetron sputtered Cu2O films. Thin Solid Films. ISSN 0040-6090. 722(31), p. 1–5. doi: 10.1016/j.tsf.2021.138573. Full text in Research Archive
• Zaborowska, A.; Kurpaska, L.; Clozel, M.; Olivier, E.J.; O'Connell, J.H. & Vanazzi, M. [Show all 13 contributors for this article] (2021). Absolute radiation tolerance of amorphous alumina coatings at room temperature. Ceramics International. ISSN 0272-8842. 47, p. 34740–34750. doi: 10.1016/j.ceramint.2021.09.013. 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
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Monakhov, Eduard & Kuznetsov, Andrej (2021). Dominating migration barrier for intrinsic defects in gallium oxide: Dose-rate effect measurements. Applied Physics Letters. ISSN 0003-6951. 118(23). doi: 10.1063/5.0051047. Full text in Research Archive
• Zhu, Mengyi; Wu, Guixuan; Azarov, Alexander; Monakhov, Eduard; Tang, Kai & Müller, Michael [Show all 7 contributors for this article] (2021). Effects of La2O3 Addition into CaO-SiO2 Slag: Structural Evolution and Impurity Separation from Si-Sn Alloy. Metallurgical and Materials Transactions B. ISSN 1073-5615. 52B(5), p. 3045–3063. doi: 10.1007/s11663-021-02232-4. Full text in Research Archive Show summary

  Boron (B) and phosphorus (P) are the most problematic impurities to be removed in the production of solar-grade silicon by the metallurgical process. In this work, the distribution of B and P between CaO-(La2O3)-SiO2 slags and Si-10 mass pct Sn melt was experimentally studied. B distribution coefficient increased from 2.93 in binary CaO-SiO2 slag to 3.33 and 3.65 with 2 and 10 mass pct La2O3 additions, respectively. In the followed acid-leaching experiments, the slag-treated Si-Sn alloys exhibited higher B and P removal than that of the initial alloy without slag treatment. Molecular dynamics simulations were performed to study the effect of La2O3 addition on the slag structural and transport properties. A novel oxygen classification method was proposed to distinguish the different structural roles of La and Ca in the CaO-La2O3-SiO2 system. It was found that La3+ prefers to stay in the depolymerized region, mostly connects with 6-7 non-bridging oxygen, and requires a weak charge compensation with Ca2+. Possible silicothermic reduction was evaluated to discuss the slag chemistry and the mass transfer between slag and metal phase. A thermodynamic model was derived to theoretically study the alloying effect on impurity distribution in slag refining where positive interaction coefficient and high alloying concentration were found most beneficial to improve the impurity removal.

• 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
• Cieślik, I.; Duchna, M.; Płociński, T.; Wyszkowska, E.; Azarov, Alexander & Zieniuk, M. (2020). Ion irradiation effect on the microstructure of Inconel 625 obtained by Selective Laser Melting and by the metallurgical process. Surface & Coatings Technology. ISSN 0257-8972. 396. doi: 10.1016/j.surfcoat.2020.125952.
• Zhu, Mengyi; Azarov, Alexander; Monakhov, Eduard; Tang, Kai & Safarian, Jafar (2020). Phosphorus separation from metallurgical-grade silicon by magnesium alloying and acid leaching. Separation and Purification Technology. ISSN 1383-5866. 240. doi: 10.1016/j.seppur.2020.116614. Full text in Research Archive Show summary

  In this paper, the separation of phosphorus from metallurgical-grade silicon was investigated based on an Mg alloying and HCl leaching approach. Experimental results show that P concentration was reduced from initial 15.1 ppmw to 0.2 ppmw with also large extent removal of metallic impurities by two times Mg alloying-leaching purification. The mechanism of enhanced P separation is clarified owing to the strong affinity between Mg and P, which is validated by SIMS elemental mapping. A two-parameter analytical model was developed to predict the P removal degree based on the variables of alloying metal concentration and interaction coefficient between alloying metal and P. The model is validated with experimental results and the interaction coefficient ε^P_{Mg In Si} was obtained as −10.8. This approach can be applied to model the removal of impurity which follows Gulliver-Scheil solidification from other binary alloying systems. Furthermore, in order to study the effect of applied alloying-leaching operation times, a model was proposed which establishes the mathematical relationships among key processing variables like initial and target P concentrations, the amount of the alloying metal, and the process operation times.

• Ellingsen, Josef Gert Åsheim; Venkatachalapathy, Vishnukanthan; Azarov, Alexander; Nilsen, Ola & Kuznetsov, Andrej (2020). Al incorporation during metal organic chemical vapour deposition of aluminium zinc oxide. Thin Solid Films. ISSN 0040-6090. 709. doi: 10.1016/j.tsf.2020.138245. 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
• Müting, Johanna; Bobal, Viktor; Azarov, Alexander; Svensson, Bengt Gunnar & Grossner, Ulrike (2019). Lateral straggling of ion implantation distributions in 4H-SiC investigated by SIMS. Materials Science Forum. ISSN 0255-5476. 963 MSF, p. 437–440. doi: 10.4028/www.scientific.net/MSF.963.437.
• Azarov, Alexander & Kuznetsov, Andrej (2019). Energetics, migration and trapping of Zn interstitials in ZnO. Journal of Physics D: Applied Physics. ISSN 0022-3727. 52(48). doi: 10.1088/1361-6463/ab3eab. Full text in Research Archive
• Bazioti, Kalliopi; Azarov, Alexander; Johansen, Klaus Magnus H; Svensson, Bengt Gunnar; Vines, Lasse & Kuznetsov, Andrej [Show all 7 contributors for this article] (2019). Role of Nitrogen in Defect Evolution in Zinc Oxide: STEM−EELS Nanoscale Investigations. The Journal of Physical Chemistry Letters. ISSN 1948-7185. 10(16), p. 4725–4730. doi: 10.1021/acs.jpclett.9b01472. Full text in Research Archive
• Azarov, Alexander; Aarseth, Bjørn Lupton; Vines, Lasse; Hallen, Anders; Monakhov, Eduard & Kuznetsov, Andrej (2019). Defect annealing kinetics in ZnO implanted with Zn substituting elements: Zn interstitials and Li redistribution. Journal of Applied Physics. ISSN 0021-8979. 125(7). doi: 10.1063/1.5083226. Full text in Research Archive
• 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
• Olsen, Vegard Skiftestad; Bazioti, Kalliopi; Baldissera, Gustavo; Azarov, Alexander; Prytz, Øystein & Persson, Clas [Show all 9 contributors for this article] (2019). Effects of Substrate and Post-Deposition Annealing on Structural and Optical Properties of (ZnO)1-x(GaN)x Films. Physica status solidi (b). ISSN 0370-1972. 256(6). doi: 10.1002/pssb.201800529. Full text in Research Archive
• Granerød, Cecilie Skjold; Aarseth, Bjørn Lupton; Nguyen, Phuong Dan; Bazioti, Kalliopi; Azarov, Alexander & Svensson, Bengt Gunnar [Show all 8 contributors for this article] (2019). Structural and optical properties of individual Zn2GeO4 particles embedded in ZnO. Nanotechnology. ISSN 0957-4484. 30(22), p. 1–6. doi: 10.1088/1361-6528/ab061c. 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.
• Jozwik, Iwona; Zielinski, Marcin S; Azarov, Alexander; Ratajczak, Renata; Mieszczynski, Cyprian & Stonert, Anna [Show all 7 contributors for this article] (2018). Low energy cathodoluminescence analysis of damage build-up in ion irradiated spinel mono- and polycrystals. Nuclear Instruments and Methods in Physics Reseach B. ISSN 0168-583X. 435, p. 290–295. doi: 10.1016/j.nimb.2017.10.030.
• Tang, Aihua; Mei, Zengxia; Hou, Yao-Nan; Liu, Lishu; Venkatachalapathy, Vishnukanthan & Azarov, Alexander [Show all 8 contributors for this article] (2018). GaZn-VZn acceptor complex defect in Ga-doped ZnO. Science China Physics, Mechanics & Astronomy. ISSN 1674-7348. 61(7), p. 1–6. doi: 10.1007/s11433-018-9195-7.
• Olsen, Vegard Skiftestad; Bazioti, Kalliopi; Azarov, Alexander; Svensson, Bengt Gunnar; Kuznetsov, Andrej & Prytz, Øystein [Show all 7 contributors for this article] (2018). Bandgap bowing in crystalline (ZnO)1-x(GaN)x thin films; influence of composition and structural properties. Semiconductor Science and Technology. ISSN 0268-1242. 34, p. 1–7. doi: 10.1088/1361-6641/aaee4a.
• 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.
• Azarov, Alexander; Wendler, Elke; Monakhov, Edouard & Svensson, Bengt Gunnar (2018). Defect stabilization and reverse annealing in ZnO implanted with nitrogen at room and cryogenic temperature. Journal of Applied Physics. ISSN 0021-8979. 123(10). doi: 10.1063/1.5022152. Full text in Research Archive
• 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.

• Azad, Fahad; Luo, Caiqin; Su, Shichen; Younas, Muhammad; Azeem, Waqar & Kuznetsov, Andrej [Show all 11 contributors for this article] (2017). Surface localization of the Er-related optical active centers in Er doped zinc oxide films. Journal of Applied Physics. ISSN 0021-8979. 121(23). doi: 10.1063/1.4986234.
• Azarov, Alexander; Wendler, Elke; Lorenz, Katharina; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Effect of buried extended defects on the radiation tolerance of ZnO. Applied Physics Letters. ISSN 0003-6951. 110(17). doi: 10.1063/1.4981808.
• 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.
• Egorov, K; Lebedinskii, Yury Yu; Soloviev, Anatoly A.; Chouprik, Anastasia A.; Azarov, Alexander & Markeev, Andrey M. (2017). Initial and steady-state Ru growth by atomic layer deposition studied by in situ Angle Resolved X-ray Photoelectron Spectroscopy. Applied Surface Science. ISSN 0169-4332. 419, p. 107–113. doi: 10.1016/j.apsusc.2017.05.010.
• Schifano, Ramon; Riise, Heine Nygard; Domagala, J.; Azarov, Alexander; Ratajczak, R. & Monakhov, Edouard [Show all 11 contributors for this article] (2017). Comparison of the structural properties of Zn-face and O-face single crystal homoepitaxial ZnO epilayers grown by RF-magnetron sputtering. Journal of Applied Physics. ISSN 0021-8979. 121(1). doi: 10.1063/1.4973342. Full text in Research Archive
• Azarov, Alexander; Rauwel, Protima; Hallen, Anders; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Extended defects in ZnO: Efficient sinks for point defects. Applied Physics Letters. ISSN 0003-6951. 110(2). doi: 10.1063/1.4973463.
• Liu, Lishu; Mei, Zengxia; Tang, Aihua; Azarov, Alexander; Kuznetsov, Andrej & Xue, Qi-Kun [Show all 7 contributors for this article] (2016). Oxygen vacancies: The origin of n-type conductivity in ZnO. Physical Review B. Condensed Matter and Materials Physics. ISSN 1098-0121. 93. doi: 10.1103/PhysRevB.93.235305.
• 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.
• Iwamoto, Naoya; Azarov, Alexander; Ohshima, Takeshi; Moe, Anne Marie & Svensson, Bengt Gunnar (2016). Thermal Stability of Deep-Level Defects in High-Purity Semi-Insulating 4H-SiC Substrate Studied by Admittance Spectroscopy. Materials Science Forum. ISSN 0255-5476. 858, p. 357–360. doi: 10.4028/www.scientific.net/MSF.858.357.
• Azarov, Alexander; Vines, Lasse; Rauwel, Protima; Monakhov, Edouard & Svensson, Bengt Gunnar (2016). Silver migration and trapping in ion implanted ZnO single crystals. Journal of Applied Physics. ISSN 0021-8979. 119. doi: 10.1063/1.4949331. Full text in Research Archive
• Riise, Heine Nygard; Olsen, Vegard Skiftestad; Azarov, Alexander; Galeckas, Augustinas; Sky, Thomas Neset & Svensson, Bengt Gunnar [Show all 7 contributors for this article] (2016). Local homoepitaxy of zinc oxide thin films by magnetron sputtering. Thin Solid Films. ISSN 0040-6090. 601, p. 18–21. doi: 10.1016/j.tsf.2015.09.043.
• Ma, Quanbao; Galeckas, Augustinas; Azarov, Alexander; Thøgersen, Annett; Carvalho, Patricia & Wright, Daniel Nilsen [Show all 13 contributors for this article] (2016). Boron-implanted 3C-SiC for intermediate band solar cells. Materials Science Forum. ISSN 0255-5476. 858, p. 291–294. doi: 10.4028/www.scientific.net/MSF.858.291. Full text in Research Archive Show summary

  Sublimation-grown 3C-SiC crystals were implanted with 2 atomic percent of boron ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 8.5×1016 atoms/cm2. The samples were then annealed at 1400, 1500 and 1600 °C for 1h at each temperature. The buried boron box-like concentration profile can reach ~2×1021 cm-3 in the plateau region. The optical activity of the incorporated boron atoms was deduced from the evolution in absorption and emission spectra, indicating possible pathway for achieving an intermediate band behavior in boron doped 3C-SiC at sufficiently high dopant concentrations.

• Syväjärvi, Mikael; Ma, Quanbao; Jokubavicius, Valdas; Galeckas, Augustinas; Sun, Jianwu & Liu, Xinyu [Show all 18 contributors for this article] (2016). Cubic silicon carbide as a potential photovoltaic material. Solar Energy Materials and Solar Cells. ISSN 0927-0248. 145, p. 104–108. doi: 10.1016/j.solmat.2015.08.029. Full text in Research Archive Show summary

  In this work we present a significant advancement in cubic silicon carbide (3C-SiC) growth in terms of crystal quality and domain size, and indicate its potential use in photovoltaics. To date, the use of 3C-SiC for photovoltaics has not been considered due to the band gap of 2.3 eV being too large for conventional solar cells. Doping of 3C-SiC with boron introduces an energy level of 0.7 eV above the valence band. Such energy level may form an intermediate band (IB) in the band gap. This IB concept has been presented in the literature to act as an energy ladder that allows absorption of sub-bandgap photons to generate extra electron–hole pairs and increase the efficiency of a solar cell. The main challenge with this concept is to find a materials system that could realize such efficient photovoltaic behavior. The 3C-SiC bandgap and boron energy level fits nicely into the concept, but has not been explored for an IB behavior. For a long time crystalline 3C-SiC has been challenging to grow due to its metastable nature. The material mainly consists of a large number of small domains if the 3C polytype is maintained. In our work a crystal growth process was realized by a new approach that is a combination of initial nucleation and step-flow growth. In the process, the domains that form initially extend laterally to make larger 3C-SiC domains, thus leading to a pronounced improvement in crystalline quality of 3C-SiC. In order to explore the feasibility of IB in 3C-SiC using boron, we have explored two routes of introducing boron impurities; ion implantation on un-doped samples and epitaxial growth on un-doped samples using pre-doped source material. The results show that 3C-SiC doped with boron is an optically active material, and thus is interesting to be further studied for IB behavior. For the ion implanted samples the crystal quality was maintained even after high implantation doses and subsequent annealing. The same was true for the samples grown with pre-doped source material, even with a high concentration of boron impurities. We present optical emission and absorption properties of as-grown and boron implanted 3C-SiC. The low-temperature photoluminescence spectra indicate the formation of optically active deep boron centers, which may be utilized for achieving an IB behavior at sufficiently high dopant concentrations. We also discuss the potential of boron doped 3C-SiC base material in a broader range of applications, such as in photovoltaics, biomarkers and hydrogen generation by splitting water

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• Azarov, Alexander (2023). Radiation disorder induced ordering.
• Azarov, Alexander; Park, Ji-Hyeon; Jeon, Dae-Woo; Monakhov, Eduard & Kuznetsov, Andrej (2023). Defect migration energies in Ga2O3 polymorphs measured by variations of temperature and flux under irradiation.
• Garcia Fernandez, Javier; Kjeldby, Snorre Braathen; Azarov, Alexander; Pokle, Anuj; Nguyen, Phuong Dan & Vines, Lasse [Show all 8 contributors for this article] (2023). Polymorph engineering and radiation tolerance in β-Ga2O3.
• Kjeldby, Snorre Braathen; Azarov, Alexander; Nguyen, Phuong Dan; Garcia Fernandez, Javier; Venkatachalapathy, Vishnukanthan & Mikšová, Romana [Show all 10 contributors for this article] (2022). Structure and luminescence properties of Si-implanted β-Ga2O3.
• Kjeldby, Snorre Braathen; Azarov, Alexander; Nguyen, Phuong Dan; Venkatachalapathy, Vishnukanthan; Mikšová, Romana & Macková, Anna [Show all 10 contributors for this article] (2022). Structural Transformation of β-Ga2O3 through Si-implantation.
• Azarov, Alexander; Bazioti, Kalliopi; Venkatachalapathy, Vishnukanthan; Vajeeston, Ponniah; Monakhov, Eduard & Kuznetsov, Andrej (2022). Disorder-induced ordering in Ga2O3 polymorphs.
• Azarov, Alexander; Bazioti, Kalliopi; Venkatachalapathy, Vishnukanthan; Vajeeston, Ponniah; Monakhov, Eduard & Kuznetsov, Andrej (2022). Ion-beam-induced phase transitions in gallium oxide: impact of the implantation temperature .
• Azarov, Alexander; Hoseinpur, Arman; Safarian, Jafar & Monakhov, Eduard (2021). Impurity analysis in Al-Si alloys by SIMS: the role of the primary beam.
• Bazioti, Kalliopi; Olsen, Vegard Skiftestad; Azarov, Alexander; Johansen, Klaus Magnus H; Kuznetsov, Andrej & Vines, Lasse [Show all 7 contributors for this article] (2021). Thermal evolution of point and extended defects in N-implanted ZnO and (ZnO)1−x(GaN)x thin films: STEM-EELS investigations.
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Monakhov, Eduard & Kuznetsov, Andrej (2021). Radiation defect dynamics in β-Ga2O3: ion flux vs irradiation temperature.
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Monakhov, Eduard & Kuznetsov, Andrej (2021). Dose-rate effect in β-Ga2O3.
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Monakhov, Eduard & Kuznetsov, Andrej (2021). Dominating migration barrier for intrinsic defects in gallium oxide at and above room temperature .
• Kjeldby, Snorre Braathen; Azarov, Alexander; Aarholt, Thomas; Prytz, Øystein & Vines, Lasse (2021). Defect-annealing in Si+-implanted β-Ga2O3.
• Bazioti, Kalliopi; Olsen, Vegard Skiftestad; Azarov, Alexander; Johansen, Klaus Magnus H; Svensson, Bengt Gunnar & Kuznetsov, Andrej [Show all 8 contributors for this article] (2020). Role of nitrogren in defect evolution in ZnO and (ZnO)₁−ₓ(GaN)ₓ: STEM-EELS nanoscale investigations.
• 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.
• Bazioti, Kalliopi; Olsen, Vegard Skiftestad; Azarov, Alexander; Kuznetsov, Andrej; Vines, Lasse & Prytz, Øystein (2019). Defect formation and thermal evolution in ZnO-based structures (Highlight talk).
• Nguyen, Phuong Dan; Granerød, Cecilie Skjold; Aarseth, Bjørn Lupton; Bazioti, Kalliopi; Azarov, Alexander & Svensson, Bengt Gunnar [Show all 8 contributors for this article] (2019). Structural and optical properties of individual Zn2GeO4 particles embedded in ZnO.
• Bazioti, Kalliopi; Olsen, Vegard Skiftestad; Johansen, Klaus Magnus H; Azarov, Alexander; Kuznetsov, Andrej & Vines, Lasse [Show all 7 contributors for this article] (2019). Transmission Electron Microscopy methods for atomic-scale investigations of semiconductor properties .
• Bazioti, Kalliopi; Azarov, Alexander; Svensson, Bengt Gunnar & Prytz, Øystein (2018). An aberration-corrected (S)TEM study of N-induced defects in ZnO: formation and thermal evolution.
• Bazioti, Kalliopi; Azarov, Alexander; Svensson, Bengt Gunnar & Prytz, Øystein (2018). (S)TEM characterization and thermal evolution of ion-induced defects in ZnO.
• Olsen, Vegard Skiftestad; Bazioti, Kalliopi; Azarov, Alexander; Granerød, Cecilie Skjold; Svensson, Bengt Gunnar & Kuznetsov, Andrej [Show all 8 contributors for this article] (2018). Bandgap bowing in crystalline (ZnO)1-x(GaN)x thin films.
• Kumar, Raj; Bergum, Kristin; Riise, Heine Nygard; Azarov, Alexander; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Impact of post deposition annealing on electrical properties of Cu2O thin films.
• 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.
• 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.
• Azarov, Alexander; Wendler, Elke; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Effect of pre-existing extended defects on radiation defect dynamics in ZnO implanted with N at room and cryogenic temperatures.
• Azarov, Alexander & Svensson, Bengt Gunnar (2017). Ion beam modification of wide bandgap semiconductors.
• Azarov, Alexander; Wendler, Elke; Hallen, Anders; Monakhov, Edouard & Svensson, Bengt Gunnar (2017). Defect interaction in ZnO investigated by sequential implantation of ions and subsequent annealing.
• Azarov, Alexander; Sabatino, Marisa Di & Monakhov, Edouard (2017). Structural characterization of Cz, multicrystalline and mono-like Si by RBS/C.
• 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.
• Azarov, Alexander; Monakhov, Edouard & Svensson, Bengt Gunnar (2016). Combined ion implantation for defect engineering in GaN and ZnO.
• Azarov, Alexander; Galeckas, Augustinas; Hallen, Anders; Monakhov, Edouard & Svensson, Bengt Gunnar (2016). Annealing of Er-implanted ZnO: formation/stability of optically active centers, defect evolution and Li behavior.
• Azarov, Alexander; Venkatachalapathy, Vishnukanthan; Mei, Zengxia; Liu, Lishu; Du, Xiaolong & Galeckas, Augustinas [Show all 7 contributors for this article] (2015). Zinc vacancy energetics revealed by self-diffusion in isotopic ZnO heterostructures.

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