Browsing Det matematisk-naturvitenskapelige fakultet by Author "Galeckas, Augustinas"

Now showing items 1-20 of 32

  • Acceptor complex signatures in oxygen-rich ZnO thin films implanted with chlorine ions 
    Azarov, Alexander; Galeckas, Augustinas; Venkatachalapathy, Vishnukanthan; Mei, Zengxia; Du, Xiaolong; Monakhov, Eduard; Kuznetsov, Andrej (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    Spectroscopic identification of defects and impurities is crucial for understanding doping asymmetry issues in ZnO and, therefore, realization of true ZnO-based bipolar devices. Chlorine (Cl) is an amphoteric impurity in ...
  • Broad luminescence from donor-complexed LiZn and NaZn acceptors in ZnO 
    Frodason, Ymir Kalmann; Johansen, Klaus Magnus H; Galeckas, Augustinas; Vines, Lasse (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Zn substitutional lithium ( Li Zn ) and sodium ( Na Zn ) acceptors and their complexes with common donor impurities ( Al Zn , Hi, and HO) in ZnO have been studied using hybrid functional calculations. The results show ...
  • Changing vacancy balance in ZnO by tuning synthesis between zinc/oxygen lean conditions 
    Venkatachalapathy, Vishnukanthan; Galeckas, Augustinas; Zubiaga, Asier; Tuomisto, Filip; Kuznetsov, Andrej (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2010)
    The nature of intrinsic defects in ZnO films grown by metal organic vapor phase epitaxy was studied by positron annihilation and photoluminescence spectroscopy techniques. The supply of Zn and O during the film synthesis ...
  • Combined Au/Ag nanoparticle creation in ZnO nanopillars by ion implantation for optical response modulation and photocatalysis 
    Macková, Anna; Jagerová, Adéla; Lalik, Ondrej; Mikšová, Romana; Poustka, David; Mistrík, Jan; Holý, Václav; Schutter, Jan David; Kentsch, Ulrich; Marvan, Petr; Azarov, Alexander; Galeckas, Augustinas (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2023)
    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. ...
  • Conversion pathways of primary defects by annealing in proton-irradiated n-type 4H-SiC 
    Karsthof, Robert Michael; Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Vines, Lasse (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    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 ...
  • Cross-sectional carrier lifetime profiling and deep level monitoring in silicon carbide films exhibiting variable carbon vacancy concentrations 
    Galeckas, Augustinas; Karsthof, Robert Michael; Gana, Kingsly; Kok, Angela; Bathen, Marianne Etzelmüller; Vines, Lasse; Kuznetsov, Andrej (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    The carrier lifetime control over 150 μm thick 4H-SiC epitaxial layers via thermal generation and annihilation of carbon vacancy (VC) related Z1/2 lifetime killer sites is reported. The defect developments upon typical SiC ...
  • Effects of annealing on photoluminescence and defect interplay in ZnO bombarded by heavy ions: Crucial role of the ion dose 
    Azarov, Alexander; Galeckas, Augustinas; Mieszczyński, Cyprian; Hallen, Anders; Kuznetsov, Andrej (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    Bombardment of ZnO with heavy ions generating dense collision cascades is of particular interest because of the formation of nontrivial damage distribution involving a defected layer located between the surface and the ...
  • Electrical charge state identification and control for the silicon vacancy in 4H-SiC 
    Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Müting, Johanna; Ayedh, Hussein Mohammed Hussein; Grossner, Ulrike; Coutinho, José; Frodason, Ymir Kalmann; Vines, Lasse (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Reliable single-photon emission is crucial for realizing efficient spin-photon entanglement and scalable quantum information systems. The silicon vacancy (VSi) in 4H-SiC is a promising single-photon emitter exhibiting ...
  • Energetic Au ion beam implantation of ZnO nanopillars for optical response modulation 
    Macková, Anna; Malinský, Petr; Jagerová, Adéla; Mikšová, Romana; Lalik, Ondrej; Nekvindová, Pavla; Mistrík, Jan; Marvan, Petr; Sofer, Zdenek; Holý, Václav; Schutter, Jan David; Kentsch, Ulrich; Azarov, Alexander; Galeckas, Augustinas (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2022)
    Abstract Nanopillars of ZnO were implanted with Au-400 keV ions at various ion fluences from 1 × 10 15 cm −2 to 1 × 10 16 cm −2 and subsequently annealed at 750 °C for 15 min in order to reduce the implantation ...
  • Enhancing the UV emission in ZnO-CNT hybrid nanostructures via the surface plasmon resonance of Ag nanoparticles 
    Rauwel, Protima; Galeckas, Augustinas; Rauwel, Erwan (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    The crystal quality and surface states are two major factors that determine optical properties of ZnO nanoparticles (NPs) synthesized through nonaqueous sol–gel routes, and both are strongly dependent on the growth conditions. ...
  • Formation and functionalization of Ge-nanoparticles in ZnO 
    Aarseth, Bjørn Lupton; Granerød, Cecilie Skjold; Galeckas, Augustinas; Azarov, Alexander; Nguyen, Phuong Dan; Prytz, Øystein; Vines, Lasse (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2021)
    Semiconductor nanocrystals are often proposed as a viable route to improve solar energy conversion in photovoltaics and photoelectrochemical systems. Embedding the nanocrystals in, e.g. a transparent and conducting electrode ...
  • Galvanic restructuring of exsolved nanoparticles for plasmonic and electrocatalytic energy conversion 
    Kang, Xiaolan; Reinertsen, Vilde Mari; Both, Kevin Gregor; Galeckas, Augustinas; Aarholt, Thomas; Prytz, Øystein; Norby, Truls; Neagu, Dragos; Chatzitakis, Athanasios (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    There is a growing need to control and tune nanoparticles (NPs) to increase their stability and effectiveness, especially for photo- and electrochemical energy conversion applications. Exsolved particles are well anchored ...
  • Ge redistribution in SiO2/SiGe structures under thermal oxidation: Dynamics and predictions 
    Long, Ethan Schuyler; Azarov, Alexander; Kløw, Frode; Galeckas, Augustinas; Kuznetsov, Andrej; Diplas, Spyridon (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    Several fundamental aspects of the oxidation-induced redistribution of Ge in thin films of SiGe are studied. This includes the incorporation of Ge into the oxide and the formation of what is alternatively referred to as ...
  • Impact of carbon injection in 4H-SiC on defect formation and minority carrier lifetime 
    Bathen, Marianne Etzelmüller; Karsthof, Robert Michael; Galeckas, Augustinas; Kumar, Piyush; Kuznetsov, Andrej; Grossner, Ulrike; Vines, Lasse (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
  • Impact of post annealing and hydrogen implantation on functional properties of Cu2O thin films for photovoltaic applications 
    Kumar, Raj; Bergum, Kristin; Riise, Heine Nygard; Monakhov, Eduard; Galeckas, Augustinas; Svensson, Bengt Gunnar (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    Polycrystalline cuprous oxide (Cu2O) thin films were sputtered, annealed (900 °C rapid thermal annealing) and subsequently implanted with various hydrogen ion (H+) doses from 5E13 to 2E15 cm−2 with a low acceleration energy ...
  • Influence of hydrogen implantation on emission from the silicon vacancy in 4H-SiC 
    Bathen, Marianne Etzelmüller; Galeckas, Augustinas; Coutinho, José; Vines, Lasse (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    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 ...
  • Monitoring selective etching of self-assembled nanostructured a-Si:Al films 
    Kjeldstad, Torunn; Thøgersen, Annett; Stange, Marit Synnøve Sæverud; Azarov, Alexander; Monakhov, Eduard; Galeckas, Augustinas (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)
    Nanoporous and nanowire structures based on silicon (Si) have a well recognized potential in a number of applications such as photovoltaics, energy storage and thermoelectricity. The immiscibility of Si and aluminum (Al) ...
  • Muon Interaction with Negative-U and High-Spin-State Defects: Differentiating Between C and Si Vacancies in 4H-SiC 
    Woerle, Judith; Bathen, Marianne Etzelmüller; Prokscha, Thomas; Galeckas, Augustinas; Ayedh, Hussein Mohammed Hussein; Vines, Lasse; Grossner, Ulrike (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    Low-energy muon-spin-rotation spectroscopy (LE-μSR) is employed to study silicon and carbon vacancies in proton-irradiated 4H-SiC. We show that the implanted muon is quickly attracted to the negative Si vacancy (VSi), where ...
  • Nano-structuring in SiGe by oxidation induced anisotropic Ge self-organization 
    Long, Ethan Schuyler; Galeckas, Augustinas; Kuznetsov, Andrej; Ronda, Antoine; Favre, Luc; Berbezier, Isabelle; Radamson, Henry H. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    The present study examines the kinetics of dry thermal oxidation of (111), (110), and (100) silicon-germanium (SiGe) thin epitaxial films and the redistribution of Ge near the oxidation interface with the aim of facilitating ...
  • Optical properties of ZnFe2O4 nanoparticles and Fe-decorated inversion domain boundaries in ZnO 
    Kjeldby, Snorre Braathen; Nguyen, Phuong Dan; García Fernández, Javier; Haug, K.; Galeckas, Augustinas; Jensen, Ingvild Julie Thue; Thøgersen, Annett; Vines, Lasse; Prytz, Øystein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    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 ...