Anette Eleonora Gunnæs

• Bundli, Silje; Dhak, Prasanta; Jensen, Martin; Gunnæs, Anette Eleonora; Nguyen, Phuong Dan; Fjellvåg, Helmer & Sjåstad, Anja Olafsen (2019). Controlled alloying of Pt-Rh nanoparticles by the polyol approach. Journal of Alloys and Compounds.  ISSN 0925-8388.  779, s 879- 885 . doi: 10.1016/j.jallcom.2018.11.301
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Almeida Carvalho, Patricia; Berland, Kristian; Sørby, Magnus Helgerud; Persson, Clas; Gunnæs, Anette Eleonora & Hauback, Bjørn (2019). Long- and short-range structures of Ti1-xHfxNi1.0/1.1Sn half-Heusler compounds and their electric transport properties. CrysteEngComm.  ISSN 1466-8033.  21, s 3330- 3342 . doi: 10.1039/C9CE00046A
• Hjelmeland, Trude Bjørgås; Bazioti, Kalliopi; Gunnæs, Anette Eleonora; Volkov, Y & Mikheenko, Pavlo (2019). Effect of colossal magnetoresistance material La0.67Ca0.33MnO3 on superconducting properties of YBa2Cu3O7-δ thin films. Journal of Magnetism and Magnetic Materials.  ISSN 0304-8853.  487 . doi: 10.1016/j.jmmm.2019.165335
• Oyama, Kohei; Diplas, Spyridon; M'hamdi, Mohammed; Gunnæs, Anette Eleonora & S. Azar, Amin (2019). Heat source management in wire-arc additive manufacturing process for Al-Mg and Al-Si alloys. Additive Manufacturing.  ISSN 2214-8604.  26, s 180- 192 . doi: 10.1016/j.addma.2019.01.007
• Bergum, Kristin; Riise, Heine Nygard; Gorantla, Sandeep Madhukar; Lindberg, Per; Jensen, Ingvild Julie Thue; Gunnæs, Anette Eleonora; Galeckas, Augustinas; Diplas, Spyridon; Svensson, Bengt Gunnar & Monakhov, Edouard (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
• Guzik, Matylda N.; Echevarria-Bonet, Cristina; Riktor, Marit Dalseth; Almeida Carvalho, Patricia; Gunnæs, Anette Eleonora; Sørby, Magnus Helgerud & Hauback, Bjørn (2018). Half-Heusler phase formation and Ni atom distribution in M-Ni-Sn (M = Hf, Ti, Zr) systems. Acta Materialia.  ISSN 1359-6454.  148, s 216- 224 . doi: 10.1016/j.actamat.2018.01.019
• Jensen, Ingvild Julie Thue; Gorantla, Sandeep Madhukar; Løvvik, Ole Martin; Gan, Jiantuo; Nguyen, Phuong Dan; Monakhov, Edouard; Svensson, Bengt Gunnar; Gunnæs, Anette Eleonora & Diplas, Spyridon (2017). Interface phenomena in magnetron sputtered Cu2O/ZnO heterostructures. Journal of Physics: Condensed Matter.  ISSN 0953-8984.  29(43) . doi: 10.1088/1361-648X/aa8799
• Lindberg, Per Filip; Gorantla, Sandeep Madhukar; Gunnæs, Anette Eleonora; Svensson, Bengt Gunnar & Monakhov, Edouard (2017). Electronic properties and morphology of copper oxide/n-type silicon heterostructures. Journal of Physics: Condensed Matter.  ISSN 0953-8984.  29(31) . doi: 10.1088/1361-648X/aa77bc
• Schrade, Matthias; Berland, Kristian; Eliassen, Simen Nut Hansen; Guzik, Matylda Natalia; Echevarria-Bonet, Cristina; Sørby, Magnus Helgerud; Jenus, Petra; Hauback, Bjørn; Tofan, Raluca; Gunnæs, Anette Eleonora; Persson, Clas; Løvvik, Ole Martin & Finstad, Terje (2017). The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X=Hf, Zr, Ti) half-Heusler alloys. Scientific Reports.  ISSN 2045-2322.  7 . doi: 10.1038/s41598-017-14013-8 Fulltekst i vitenarkiv.
• Gan, Jiantuo; Gorantla, Sandeep Madhukar; Riise, Heine Nygard; Fjellvåg, Øystein Slagtern; Diplas, Spyridon; Løvvik, Ole Martin; Svensson, Bengt Gunnar; Monakhov, Edouard & Gunnæs, Anette Eleonora (2016). Structural properties of Cu2O epitaxial films grown on c-axis single crystal ZnO by magnetron sputtering. Applied Physics Letters.  ISSN 0003-6951.  108:152110(15), s 1- 5 . doi: 10.1063/1.4945985 Vis sammendrag

  Epitaxial Cu2O films grown by reactive and ceramic radio frequency magnetron sputtering on single crystalline ZnO (0001) substrates are investigated. The films are grown on both O- and Zn-polar surface of the ZnO substrates. The Cu2O films exhibit a columnar growth manner apart from a ∼5 nm thick CuO interfacial layer. In comparison to the reactively sputtered Cu2O, the ceramic-sputtered films are less strained and appear to contain nanovoids. Irrespective of polarity, the Cu2O grown by reactive sputtering is observed to have (111)Cu2O||(0001)ZnO epitaxial relationship, but in the case of ceramic sputtering the films are found to show additional (110)Cu2O reflections when grown on O-polar surface. The observed CuO interfacial layer can be detrimental for the performance of Cu2O/ZnO heterojunction solar cells reported in the literature.

• Gunnæs, Anette Eleonora; Gorantla, Sandeep Madhukar; Løvvik, Ole Martin; Gan, Jiantuo; Carvalho, Patricia; Svensson, Bengt Gunnar; Monakhov, Edouard; Bergum, Kristin; Jensen, Ingvild Julie Thue & Diplas, Spyridon (2016). Epitaxial strain-induced growth of CuO at Cu2O/ZnO interfaces. Journal of Physical Chemistry C.  ISSN 1932-7447.  120(41), s 23552- 23558 . doi: 10.1021/acs.jpcc.6b07197 Vis sammendrag

  Cu2O/ZnO has been envisaged as a potential material system for the next generation thin film solar cells. So far, the experimental efforts to obtain conversion efficiencies close to the theoretically predicted value have failed. Combining aberration-corrected (scanning) transmission electron microscopy and density functional theory modelling, we have studied the interfaces between single crystal c-axis oriented ZnO and high-quality magnetron sputtered Cu2O films. Strikingly, our study shows that the first ~5 nm of the Cu-oxide films have the structure of the monoclinic CuO phase. The CuO layer is textured with the (111), (11¯1), (¯111), (1¯1 ¯1), (¯1 ¯11), (1¯11), (¯11¯1) and (100) planes parallel to the (0001) and (000¯1) ZnO interfaces. The ionic arrangement on these planes resembles the hexagonal arrangement of the ZnO interface and epitaxy exists across the interface. A continued epitaxial growth of [111] oriented Cu2O follows resulting in epitaxial 180o rotation twins in the Cu2O layer. For the case with the (100)CuO interfacial plane we have: (111)[1¯10]Cu2O II (100)[011]CuO II (0001)[11¯20]ZnO. Because of a closer lattice matching of CuO with ZnO and Cu2O, the total strain and energy is reduced compared to a pure (111)Cu2O II (0001)ZnO interface. The existence of CuO is anticipated to be a contributing factor for the low conversion efficiencies obtained experimentally.

• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora; Luxsacumar, Sivakanesar; Løvvik, Ole Martin; Snyder, Jeffrey G. & Finstad, Terje (2015). Nanostructuring of undoped ZnSb by Cryo-Milling. Journal of Electronic Materials.  ISSN 0361-5235.  44(8), s 2578- 2584 . doi: 10.1007/s11664-015-3708-6 Vis sammendrag

  We report the preparation of nanosized ZnSb powder by cryo-milling. The effect of cryo-milling then hot-pressing of undoped ZnSb was investigated and compared with that of room temperature ball-milling and hot-pressing under different temperature conditions. ZnSb is a semiconductor with favorable thermoelectric properties when doped. We used undoped ZnSb to study the effect of nanostructuring on lattice thermal conductivity, and with little contribution at room temperature from electronic thermal conductivity. Grain growth was observed to occur during hot-pressing, as observed by transmission electron microscopy and x-ray diffraction. The thermal conductivity was lower for cryo-milled samples than for room-temperature ball-milled samples. The thermal conductivity also depended on hot-pressing conditions. The thermal conductivity could be varied by a factor of two by adjusting the process conditions and could be less than a third that of single-crystal ZnSb.

• Hage, Fredrik Sydow; Kepaptsoglou, Despoina Maria; Seabourne, Ché Royce; Ramasse, Quintim M.; Scott, Andrew J.; Prytz, Øystein; Gunnæs, Anette Eleonora & Helgesen, Geir (2014). Dielectric response of pentagonal defects in multilayer graphene nano-cones. Nanoscale.  ISSN 2040-3364.  6(3), s 1833- 1839 . doi: 10.1039/c3nr05419e
• Nguyen, Phuong Dan; Gunnæs, Anette Eleonora; Sunding, Martin Fleissner & Olsen, Arne (2014). Heterogeneous nucleation and growth of CrSi2 in sputtered thin films of silicon/silicon nitride. Thin Solid Films.  ISSN 0040-6090.  556, s 200- 205 . doi: 10.1016/j.tsf.2014.01.080
• Bleken, Bjørn Tore Lønstad; Wragg, David; Arstad, Bjørnar; Gunnæs, Anette Eleonora; Mouzon, Johanne; Helveg, Stig; Lundegaard, Lars Fahl; Beato, Pablo; Bordiga, Silvia; Olsbye, Unni; Svelle, Stian & Lillerud, Karl Petter (2013). Unit cell thick nanosheets of zeolite H-ZSM-5: Structure and activity. Topics in catalysis.  ISSN 1022-5528.  56(9-10), s 558- 566 . doi: 10.1007/s11244-013-0010-9 Vis sammendrag

  Nanosheets of zeolite H-ZSM-5 were synthesized and characterized by X-ray diffraction, transmission electron microscopy (TEM), N2-physisorption, FT-IR spectroscopy, 27Al and 29Si MAS NMR spectroscopy in addition to catalytic testing in conversion of methanol to hydrocarbons (MTH). It was found that Rietveld analysis, involving anisotropic broadening parameters, gave average crystallite dimensions in good agreement with TEM images. The selectivities in MTH is intact in the mesoporous nanosheet H-ZSM-5 with the largest difference being a higher C3/C2 ratio compared to regular H-ZSM-5.

• Hage, Fredrik Sydow; Ramasse, Quentin; Kepaptsoglou, Despoina Maria; Prytz, Øystein; Gunnæs, Anette Eleonora; Helgesen, Geir & Brydson, Rik (2013). Topologically induced confinement of collective modes in multilayer graphene nanocones measured by momentum-resolved STEM-VEELS. Physical Review B. Condensed Matter and Materials Physics.  ISSN 1098-0121.  88(15) . doi: 10.1103/PhysRevB.88.155408
• Hadidi, Kianoosh; Hancke, Ragnhild; Norby, Truls; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2012). Atomistic study of LaNbO4; surface properties and hydrogen adsorption. International journal of hydrogen energy.  ISSN 0360-3199.  37(8), s 6674- 6685 . doi: 10.1016/j.ijhydene.2012.01.065 Vis sammendrag

  We have calculated fundamental properties of pure and hydrogen-covered (010), (101), (100) and (001) surfaces of the low temperature monoclinic phase of LaNbO4 (LN). The (010) surface was the most stable one, exhibiting electronic structure and local geometric configurations similar to bulk. As the first stage of proton migration into the electrolyte, the ability of LN surfaces to split H2 molecules was probed indirectly by calculating the adsorption energy of H atoms on two of the LN surfaces. H adsorption on the (010) surface was found to be strongly endothermic, and thus cannot contribute much in splitting H2. The adsorption energy on the relatively unstable (101) surface was on the other hand approximately −0.6 eV, in the right range for surface H2 to be catalyzed beneficially. H adsorption on this surface was induced by surface states in the band gap of the clean surface. Since the unstable (101) surface is not abundant, the rate of dissociative adsorption of H2 on the LN surface can be anticipated to be very low. Application of the energies to simple adsorption isotherm calculations for typical proton conducting fuel cells (PCFCs) operating temperatures correspondingly showed very low H coverage, and it is not expected that LaNbO4 surfaces can contribute much to the H2 activation reaction of a PCFC anode.

• Hadidi, Kianoosh; Norby, Truls; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2012). Hydrogen energetics and charge transfer in the Ni/LaNbO4 interface from DFT calculations. International journal of hydrogen energy.  ISSN 0360-3199.  37(9), s 8033- 8042 . doi: 10.1016/j.ijhydene.2011.11.032 Vis sammendrag

  Calculations based on density functional theory have been used to simulate interface structures between the tetragonal and monoclinic phases of LaNbO4 (LN) and Ni. Schottky barrier heights were calculated using the interface electronic structure; they were 3.0 and 1.8 eV for p- and n-type barriers. The hydrogen interstitials were found to be significantly higher stable in the LN part of the interface than in bulk LN. Also, the potential energy curve of hydrogen diffusion from Ni into LN exhibited a deep well of around 2 eV, located in the gap region between two components. The stability of H atom in the gap region and interfacial layers of LN is explained by metal-induced gap states and indicates that there will be an accumulation of hydrogen in this area. It was shown that hydrogen is ionized when enters from Ni to the LN interfacial layer, approaching to the O atoms and that the electron lost from hydrogen resides in the interface states, located in the band gap of LN.

• Kepaptsoglou, Despoina Maria; Hadidi, Kianoosh; Løvvik, Ole Martin; Magraso, Anna; Norby, Truls; Gunnæs, Anette Eleonora; Olsen, Arne & Ramasse, Quentin (2012). Interfacial Charge Transfer and Chemical Bonding in a Ni-LaNbO4 Cermet for Proton-Conducting Solid-Oxide Fuel Cell Anodes. Chemistry of Materials.  ISSN 0897-4756.  24(21), s 4152- 4159 . doi: 10.1021/cm302317f Vis sammendrag

  In this work, we present an atomic scale study of the structural and chemical characteristics of interfaces between Ni and LaNbO4 grains in Ni–LaNbO4 cermets, a model composite material for anodes in proton-conducting solid-oxide fuel cells (SOFC). Electron energy loss spectroscopy (EELS) performed in an aberration-corrected scanning transmission electron microscope reveals the absence of reaction or interdiffusion layers at the interface. Changes in the valence state of Ni as well as in the electronic structure of La, reflected by changes in the EELS fine features at the interface, are shown to be related to charge transfer across the interface. The experimental results are in excellent agreement with ab initio calculations based on density functional theory, which predict that direct chemical bonds are formed between the metal and the ceramic at this abrupt interface, resulting in a redistribution of electronic charge across the interface.

• Magraso Sola, Anna; Frontera, Carlos; Gunnæs, Anette Eleonora; Tarancon, Albert; Marrero-López, David; Norby, Truls & Haugsrud, Reidar (2011). Structure, chemical stability and mixed proton-electron conductivity in BaZr0.9-xPrxGd0.1O3-delta. Journal of Power Sources.  ISSN 0378-7753.  196(22), s 9141- 9147 . doi: 10.1016/j.jpowsour.2011.06.076
• Sunding, Martin Fleissner; Hadidi, Kianoosh; Diplas, Spyridon; Løvvik, Ole Martin; Norby, Truls & Gunnæs, Anette Eleonora (2011). XPS characterisation of in situ treated lanthanum oxide and hydroxide using tailored charge referencing and peak fitting procedures. Journal of Electron Spectroscopy and Related Phenomena.  ISSN 0368-2048.  184(7), s 399- 409 . doi: 10.1016/j.elspec.2011.04.002
• Diplas, Spyridon; Løvvik, Ole Martin; Nordmark, Heidi; Kepaptsoglou, Despoina Maria; Graff, Joachim Seland; Ladam, Cecile; Tyholdt, Frode; Walmsley, John; Gunnæs, Anette Eleonora; Fagerberg, Ragnar & Ulyashin, Alexander (2010). Characterization of thin and ultrathin transparent conducting oxide (TCO) films and TCO-Si interfaces with XPS, TEM and ab initio modeling. Surface and Interface Analysis.  ISSN 0142-2421.  42(6-7), s 874- 877 . doi: 10.1002/sia.3355
• Sunding, Martin Fleissner; Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Norby, Truls & Gunnæs, Anette Eleonora (2010). XPS characterisation of the interface between anode and electrolyte in a proton conducting solid oxide fuel cell. Surface and Interface Analysis.  ISSN 0142-2421.  42(6-7), s 568- 571 . doi: 10.1002/sia.3383
• Prytz, Øystein; Gunnæs, Anette Eleonora; Karlsen, Ole Bjørn; Breivik, Tallak Harald; Toberer, E. S.; Snyder, G. J. & Taftø, Johan (2009). Nanoscale inclusions in the phonon glass thermoelectric material Zn4Sb3. Philosophical Magazine Letters.  ISSN 0950-0839.  89(6), s 362- 369 . doi: 10.1080/09500830902950464
• Diplas, Spyridon; Knutsen, T; Jørgensen, Sissel; Gunnæs, Anette Eleonora; Våland, T.; Norby, Truls; Olsen, Arne & Taftø, Johan (2008). An experimental study of the electronic structure of anodically grown films on an amorphous Ni78Si8B14 alloy. Surface and Interface Analysis.  ISSN 0142-2421.  40(3-4), s 826- 829 . doi: 10.1002/sia.2748
• Fjeld, Harald; Haugsrud, Reidar; Gunnæs, Anette Eleonora & Norby, Truls (2008). Proton and oxide ion conductivity in the grain interior and grain boundaries of Ca-doped Er₂Ti₂O₇ with Si impurities. Solid State Ionics.  ISSN 0167-2738.  179(33-34), s 1849- 1853
• Polychronopoulou, K; Neidhardt, J; Rebholz, C; Baker, MA; O'Sullivan, M; Reiter, AE; Gunnæs, Anette Eleonora; Giannakopoulos, K & Mitterer, C (2008). Synthesis and characterization of Cr-B-N coatings deposited by reactive arc evaporation. Journal of Materials Research.  ISSN 0884-2914.  23(11), s 3048- 3055 . doi: 10.1557/JMR.2008.0370
• Tonheim, C.R.; Selvig, E.; Nicolas, S.; Gunnæs, Anette Eleonora; Breivik, M & Haakenaasen, R (2008). Excitation density dependence of the photoluminescence from CdxHg1-xTe multiple quantum wells. Journal of Physics, Conference Series.  ISSN 1742-6588.  100, s 042024 . doi: 10.1088/1742-6596/100/4/042024
• Breivik, Tallak Harald; Diplas, Spyridon; Ulyashin, A. G.; Gunnæs, Anette Eleonora; Olaisen, Birger Retterstøl; Holt, Arve; Olsen, Arne & Wright, Daniel Nilsen (2007). Nano-structural properties of ZnO films for Si based heterojunction solar cells. Thin Solid Films.  ISSN 0040-6090.  515, s 8479- 8483 . doi: 10.1016/j.tsf.2007.03.095
• Diplas, Spyridon; Ulyashin, Alexander; Maknys, Kestutis; Gunnæs, Anette Eleonora; Jørgensen, Sissel; Watts, J.F.; Olsen, Arne; Finstad, Terje & Wright, Daniel Nilsen (2007). On the processing-structure-property relationship of ITO layers deposited on crystalline and amorphous Si. Thin Solid Films.  ISSN 0040-6090.  515, s 8539- 8543 . doi: 10.1016/j.tsf.2007.03.091 Vis sammendrag

  Indium-tin-oxide(ITO)antireflection coatings were deposited on crystalline Si(c-Si), amorphoushydrogenatedSi(a-Si:H)and glass substrates at room temperature(RT), 160 °C and 230 °C by magnetron sputtering. The films were characterised using atomic force microscopy, transmission electron microscopy, angle resolved X-ray photoelectron spectroscopy, combined with resistance and transmittance measurements. The conductivity and refractive index as well as the morphology of the ITO films showed a significant dependence on the processing conditions. The films deposited on the two different Si substrates at higher temperatures have rougher surfaces compared to the RT ones due to the development of crystallinity and growth of columnar grains.

• Tyholdt, Frode; Fjellvåg, Helmer; Gunnæs, Anette Eleonora & Olsen, Arne (2007). Synthesis of epitaxial BiFeO3 films by chemical solution deposition on Pt(100). Journal of Applied Physics.  ISSN 0021-8979.  102 . doi: 10.1063/1.2784999 Vis sammendrag

  Thin (012) oriented epitaxial films of rhombohedral (R3c) BiFeO3, ~120 nm thickness, were obtained by means of chemical solution deposition on MgO(100)/Pt(100) substrates using an alkoxide based precursor system. X-ray diffraction and transmission electron microscopy (TEM) analysis confirmed good epitaxial matching to the substrate. The results show that careful control of the bismuth excess used for counterbalancing evaporation during crystallization is required. In contrast to lead-containing systems such as PZT, where Pb is pushed to the surface by the crystallization front where it evaporates, the Bi excess forms a Bi-rich phase at the BiFeO3/Pt interface. This phase is believed to represent a Fe substituted version of the high temperature phase -Bi2O3. TEM analysis shows that this phase grows on the substrate with (111) and (001) orientation. It is further found that BiFeO3 grows with (012) orientation on this phase as well, making an overall epitaxial film of BiFeO3 possible. Crystallization theory was applied to explain the presence of a Bi-rich secondary phase.

• Christensen, Jens S.; Kuznetsov, Andrej; Gunnæs, Anette Eleonora; Svensson, Bengt Gunnar & Radamson, H.H. (2006). Phosphorus diffusion in the presence of threading dislocations in strain relaxed SiGe films. Materials Science in Semiconductor Processing.  ISSN 1369-8001.  9, s 650- 654
• Heng, Chenglin; Li, Yanjun; Mayandi, Jeyanthinath; Finstad, Terje; Jørgensen, Sissel; Gunnæs, Anette Eleonora; Olsen, Arne & Storås, P. (2006). A study on the precipitation of Ge-rich nanoparticles in a luminescent (Er, Ge) co-doped SiO2 film sputtered with Ar+O2 plasma. International Journal of Nanoscience.  ISSN 0219-581X.  5(4-5), s 493- 498 . doi: 10.1142/S0219581X06004681 Vis sammendrag

  We report the photoluminescence (PL) from an (Er, Ge) co-doped SiO2 film deposited by rf-magnetron sputtering in an Ar + O2 ambience. The sample film was annealed in N2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge-rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.

• Sørby, Magnus; Gunnæs, Anette Eleonora; Løvvik, Ole Martin; Brinks, H. W.; Fjellvåg, Helmer & Hauback, Bjørn (2006). The crystal structure of Zr2NiD4.5. Acta Crystallographica Section B: Structural Science.  ISSN 0108-7681.  62, s 972- 978
• Gunnæs, Anette Eleonora; Skogstad, Asbjørn; Olsen, Arne & Erik, Bye (2005). Morphology and structure of airborn beta-SiC fibres produced during the industrial production of non-fibrous silicon carbide. Journal of Materials Science.  ISSN 0022-2461.  40, s 6011- 6017
• Tyholdt, Frode; Gunnæs, Anette Eleonora; Jørgensen, Sissel & Fjellvåg, Helmer (2005). Synthesis of Oriented BiFeO3 thin films by chemical solution deposition: Phase, texture, and microstructural development. Journal of Materials Research.  ISSN 0884-2914.  20(8), s 2127- 2139
• Heng, Chenglin; Finstad, Terje; Li, Yanjun; Gunnæs, Anette Eleonora; Olsen, Arne & Storås, Preben (2005). Ge nanoparticle formation and photoluminescence in Er doped SiO2 films: influence of sputter gas and annealing. Microelectronics Journal.  ISSN 0959-8324.  36, s 531- 535 Vis sammendrag

  The Er 3C luminescence at 1.54 mm is of current interest as silica-based optical fibers have low loss at that wavelength. The effect of placing Er in matrixes that are compatible with Si-integrated circuit technology has been explored and Er-doped Si-rich Si oxide has created much interest recently. In this work, we report on photoluminescence (PL) from Er-doped Ge-rich SiO2 films deposited on Si substrates and the effect of ArCO2 vs. Ar as sputtering ambience is compared. The most intense PL is reached after annealing at 700 8C for the Ar sputtering ambience. These films contain Ge rich amorphous clusters observed by transmission electron microscopy. Higher annealing temperatures yield Ge nanocrystals while lower the PL intensity. For films sputtered in an ArCO2 gas the PL intensity increases with annealing temperature up to 1000 8C while no Ge nanocrystals form.

• Kartopu, G; Karavanskii, V.A.; Serincan, U.; Turan, Rasit; Hummel, R.E.; Ekinci, Y; Gunnæs, Anette Eleonora & Finstad, Terje (2005). Can chemically etched germanium or germanium nanocrystals emit visible photoluminescence?. Physica status solidi. A, Applied research.  ISSN 0031-8965.  202, s 1472- 1476 Vis sammendrag

  Photoluminescence (PL) properties of various Ge-based nanostructured materials, prepared using methods such as chemical etching, ion implantation and spark processing, have been studied. The PL was much stronger from the samples containing Ge nanocrystals, in comparison with their counterparts with no or less Ge nanoparticles, hinting at the likely role of the quantum confinement in Ge nanocrystals (NCs) in the light emission process. On the other hand, defects in the oxides or Ge�O bonded material alone are also shown to emit light in the same energy zone as with the Ge NCs. Discussion on these results is presented.

• Heng, Chenglin; Finstad, Terje; Storås, Preben; Li, Yanjun; Gunnæs, Anette Eleonora & Nilsen, Ola (2004). The 1.54 µm photoluminescence from an (Er,Ge) co-doped SiO2 film deposited on Si by rf magnettron sputtering. Applied Physics Letters.  ISSN 0003-6951.  85(19), s 4475- 4477 Vis sammendrag

  In this work, we report on quite strong 1.54-µm photoluminescence (PL) from an (Er, Ge) co-doped SiO2 film deposited by rf magnetron sputtering. The PL intensity reaches a maximum value after the film is annealed at 700  °C for 30  min in N2. High-resolution transmission electron microscopy observation, together with energy dispersive x-ray spectroscopy analysis, indicates that amorphous Ge-rich nanoclusters precipitate in the film after 700  °C annealing. X-ray diffraction shows the presence of Ge nanocrystals after 900  °C annealing, and increasing Ge nanocrystal size with increasing annealing temperature up to 1100  °C. The results suggest that the amorphous Ge-rich nanoclusters are more effective than Ge nanocrystals in exciting the Er3+ PL.

• Marstein, Erik; Gunnæs, Anette Eleonora; Olsen, Arne; Finstad, Terje; Turan, Rasit & Serincan, U. (2004). Introduction of Si/SiO2 interface states by annealing Ge-implanted films. Journal of Applied Physics.  ISSN 0021-8979.  96, s 4308- 4312
• Serincan, U.; Kartopu, G; Gunnæs, Anette Eleonora; Finstad, Terje; Turan, Rasit; Ekinci, Y & Bayliss, S. C. (2004). Characterization of Ge nanocrystals embedded in SiO2 by Raman spectroscopy. Semiconductor Science and Technology.  ISSN 0268-1242.  19, s 247- 251 Vis sammendrag

  Ge nanocrystals formed in a SiO2 matrix by ion implantation were studied by Raman spectroscopy. It is shown that Raman analysis based on the phonon confinement model yields a successful explanation of the peculiar characteristics resulting from the nanocrystals. A broadening and a shift in the Raman peak are expected to result from the reduced size of the crystals. Asymmetry in the peak is attributed to the variations in the size of the nanocrystals. These effects were observed experimentally for the Ge nanocrystals prepared by ion implantation and explained theoretically by incorporating the effect of size and size distribution into the theoretical description of the Raman shift. A comparison with the transmission electron microscopy images indicated that this analysis could be used to estimate the structural properties of nanocrystals embedded in a host matrix. The evolution of nanocrystal formation with annealing temperature, i.e. the size growth, was monitored by Raman spectrometry for several samples and the corresponding nanocrystal sizes were estimated using the phonon confinement model.

• Marstein, Erik Stensrud; Gunnæs, Anette Eleonora; Serincan, U.; Jørgensen, Sissel; Olsen, Arne; Turan, Rasit & Finstad, Terje (2003). Mechanisms of void formation in Ge implanted SiO2 films. Nuclear Instruments and Methods in Physics Reseach B.  ISSN 0168-583X.  207(4), s 424- 433

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• Jørgensen, Sissel & Gunnæs, Anette Eleonora (ed.) (2003). Proceedings Scandem 2003. SCANDEM.  160 s.

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• de Ruiter, Lisa; Austrheim, Håkon Olaf; Dysthe, Dag Kristian & Gunnæs, Anette Eleonora (2018). Quartz weathering associated with magnesium silicate hydrate cement precipitation.
• de Ruiter, Lisa; Austrheim, Håkon Olaf; Gunnæs, Anette Eleonora & Dysthe, Dag Kristian (2018). Quartz dissolution and M-S-H cement precipitation in a high pH ultramafic system.
• Løberg, Monika; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2018). Energy Conversion using Phase Transforming Materials - the Cu-Pd-Sn system.
• Løberg, Monika; Løvvik, Ole Martin & Gunnæs, Anette Eleonora (2018). Martensitic like phase transformations in the Cu-Pd-Sn system.
• Strandbakke, Ragnar; Gunnæs, Anette Eleonora; Carvalho, Patricia A.; Mielewczyk-Gryn, Aleksandra; Wachowski, Sebastian; Balaguer, Maria; Sørby, Magnus Helgerud & Norby, Truls Eivind (2018). Coupled hydration, cation reorganization and red-ox in MIEC perovskites.
• Berland, Kristian; Eliassen, Simen Nut Hansen; Schrade, Matthias; Tofan, Raluca; Guzik, Matylda Natalia; Gunnæs, Anette Eleonora; Finstad, Terje; Katre, Anikta; Madsen, Georg; Persson, Clas & Løvvik, Ole Martin (2017). Using theory to understand thermoelectric materials.
• Gunnæs, Anette Eleonora (2017). Evaluation of a thermoelectric p-n junction at the macro and nano scale by X-ray and electron probe techniques.
• Gunnæs, Anette Eleonora; Diplas, Spyros & Ulyashin, Alexander G. (2017). A TEM and XPS study of epitaxially grown amorphous hydrogenated silicon in solar cell structures.
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Berland, Kristian; Gunnæs, Anette Eleonora; Persson, Clas; Sørby, Magnus Helgerud & Hauback, Bjørn (2017). Structural Investigation of Ti1-xHfxNiySn Half-Heusler Compounds.
• Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Gunnæs, Anette Eleonora & Ulyashin, Alexander (2017). On the evolution of properties of ITO layers deposited on crystalline and amorphous Si upon heat treatments.
• Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Ramasse, Quentin; Gunnæs, Anette Eleonora & Ulyashin, Alexander (2017). A high resolution electron microscopy and spectroscopy study of interfaces in Si-based solar cell heterojunctions.
• Løberg, Monika & Gunnæs, Anette Eleonora (2017). Influence of Mn Stoichiometry on the Structure and Thermoelectric Properties of CaMn(1+y)O(3-d). Vis sammendrag

  The energy consumption of present day society is ever increasing and the sources for more and cleaner energy is sought for. A possible contributor are thermoelectric generators, which convert parts of a heat flux directly into electrical energy. Unfortunately, the efficiency of current generators is too low for large scale commercialization, and new and better materials must be designed. In the present master project, the performance of n-type thermoelectric oxide CaMn(1+y)O(3-d) is attempted improved by creating precipitates within the nano-range. The precipitates could be anticipated to enhance phonon scattering, thereby lowering thermal conductivity and enhance the overall thermoelectric properties of the material. A sample series of CaMn(1+y)O(3-d), with composition y = 0, 0.020 , 0.036, 0.074 and 0.10, has been synthesized by solid state reaction and the microstructure and thermoelectric properties were characterized. Secondary phase, CaMn2O4, precipitates were found from X-ray diffraction and Scanning Electron Microscopy in the size range 5-10 um. Further investigations into the presence of nanoprecipitates were performed by Transmission Electron Microscopy finding no areas enriched in manganese within the CaMnO3 matrix. Electrical resistivity and Seebeck coefficient were measured from room temperature up to 600C finding a resistivity ranging from 20 - 100 mOhm cm and Seebeck coefficient from -300 to -200 uVK-1, showing no trend with manganese content. Thermal conductivity measurements were performed, showing a thermal conductivity between 2.3 - 3.6 Wm-1K-1, however no trend with varying manganese content was observed. Further, the obtained thermoelectric data was compared with samples fabricated using a different synthesis method, yielding similar results and no significant variations was observed. The absence of a Mn-dependency in all transport parameters was carefully confirmed by a thorough investigation of potential experimental influences, like sample porosity, impurity level and measurement uncertainty. Finally, the results are qualitatively rationalized using a simple Callaway model for the thermal conductivity. The concluding remarks are that all manganese excess will manifest as secondary phase CaMn2O4 and no manganese rich precipitates will exist within the CaMnO3 matrix. The variation in manganese content does not influence the thermoelectric properties of CaMn(1+y)O(3-d).

• Granerød, Cecilie Skjold; Nguyen, Phuong Dan; Gunnæs, Anette Eleonora & Prytz, Øystein (2016). The Structure Physics group.
• Gunnæs, Anette Eleonora (2016). Nanoscience with TEM at the Center for Material Science and Nanotechnology/NORTEM, Oslo, Norway.
• Lervik, Adrian; Bjørheim, Tor Svendsen; Nguyen, Phuong Dan; Diplas, Spyridon; Haugsrud, Reidar & Gunnæs, Anette Eleonora (2016). Chemical and Structural Investigations of Grain Boundaries in Y-Doped BaZrO3.
• Lervik, Adrian; Haugsrud, Reidar; Diplas, Spyridon & Gunnæs, Anette Eleonora (2016). Structural- and Compositional Investigations of Grain Boundaries in Y-Doped BaZrO3.
• Schrade, Matthias; Echevarria-Bonet, Cristina; Eliassen, Simen Nut Hansen; Berland, Kristian; Persson, Clas; Tofan, Raluca; Løvvik, Ole Martin; Gunnæs, Anette Eleonora & Finstad, Terje (2016). Thermal Properties of XNiSn(X = Hf, Zr, Ti) half Heusler Alloys.
• Schrade, Matthias; Echevarria-Bonet, Cristina; Guzik, Matylda Natalia; Tofan, Raluca; Gunnæs, Anette Eleonora; Eliassen, Simen Nut Hansen; Berland, Kristian; Persson, Clas; Løvvik, Ole Martin & Finstad, Terje (2016). Thermal properties of XNiSN (X = Ti, Zr, Hf) half Heusler alloys.
• Tofan, Raluca; Echevarria-Bonet, Cristina; Berland, Kristian; Schrade, Matthias; Sørby, Magnus Helgerud; Hauback, Bjørn Christian; Persson, Clas; Prytz, Øystein; Hansen, Vidar & Gunnæs, Anette Eleonora (2016). Microstructural characterization of spark plasma sintered (X,X’)NiSn half‐Heusler alloys.
• Tofan, Raluca; Echevarria-Bonet, Cristina; Berland, Kristian; Schrade, Matthias; Sørby, Magnus Helgerud; Hauback, Bjørn Christian; Persson, Clas; Prytz, Øystein; Hansen, Vidar & Gunnæs, Anette Eleonora (2016). The effect of spark plasma sintering on structure and phase stability in half-Heusler thermoelectric alloys.
• Echevarria-Bonet, Cristina; Tofan, Raluca; Schrade, Matthias; Gunnæs, Anette Eleonora; Persson, Clas; Sørby, Magnus Helgerud & Hauback, Bjørn (2015). Enhancement of the thermoelectric properties in nanostructured half-Heusler alloys.
• Fjellvåg, Øystein Slagtern; Sjåstad, Anja Olafsen; Haugsrud, Reidar & Gunnæs, Anette Eleonora (2015). Investigation of Novel Hydride Oxides for Holistic Understanding of Functional Materials.
• Gunnæs, Anette Eleonora (2015). Atomkikking med Norges supermikroskop.
• Lervik, Adrian; Haugsrud, Reidar; Diplas, Spyridon & Gunnæs, Anette Eleonora (2015). A TEM approach to BZY.
• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora; Carbalho, Partricia; Luxsacumar, Sivakanesar; Løvvik, Ole Martin; Snyder, G. Jeffrey & Finstad, Terje (2015). Nano Improves Thermoelectric Performance. Vis sammendrag

  The rule of thumb for improving the performance of thermoelectric materials is to reduce the thermal conduction, which attributes to electron transport and phonon transport. Phonons are characterized by different wavelength, Short wavelength phonons are scattered by impurity atoms in alloyed matels, Mid- and Long wavelength phonns are scattered by the iuinterfaces. Nanostructuring can engineer the phonon transport by introduce numerous grain boundaries, thus increasing phonon scattering, further improving thermal resistance. The aim of the present study is the nano-grains of the thermoelectric material ZnSb and the correlation with thermal transport measurements. We explored cryomilling (by ball-milling powders at Cryogenic temperature) as a technique to created nano—powders of ZnSb for pressing into pellets. The effect of cryomilling flowed by hot-pressing of undoped ZnSb was investigated.

• Ulvestad, Asbjørn; Mæhlen, Jan Petter; Andersen, Hanne Flåten; Gunnæs, Anette Eleonora; Prytz, Øystein & Kirkengen, Martin (2015). Characterization of PECVD-Grown a-SiC:H for use as Coating for Silicon Thin Film Anodes in Li-Ion Batteries.
• Løvvik, Ole Martin; Song, Xin; Valset, Kjetil; Flage-Larsen, Espen; Fjeld, Harald; Graff, Joachim Seland; Schrade, Matthias; Karlsen, Ole Bjørn; Larsson, Andreas; Casolo, Simone; Prytz, Øystein; Norby, Truls; Finstad, Terje; Gunnæs, Anette Eleonora & Taftø, Johan (2014). Thermoelectric materials from first principles to final applications: Basic and applied thermoelectrics in Oslo.
• Song, Xin; Persson, Clas; Norby, Truls; Flage-Larsen, Espen; Karlsen, Ole Bjørn; Hansen, Vidar; Gunnæs, Anette Eleonora; Prytz, Øystein; Løvvik, Ole Martin; Finstad, Terje; Valset, Kjetil; Cui, Xuemei; Taftø, Johan; Fjeld, Harald; Hauback, Bjørn & Schrade, Matthias (2014). Conversion of Heat and Energy: Thermoelectrics.
• Song, Xin; Valset, Kjetil; Graff, Joachim Seland; Thøgersen, Annett; Gunnæs, Anette Eleonora; Luxsacumar, Sivakanesar; Løvvik, Ole Martin & Finstad, Terje (2014). Nanostructuring by Cryomilling of Undoped ZnSb.
• Roaldset, Elen; Bering, Dag; Aerts, Maarten & Gunnæs, Anette E. (2013). Kaolinite Group minerals from weathered anorthosite, SW Norway. Berichte derDeutschen Ton- und Tonmineralgruppe e.V..  ISSN 1432-7007.  15, s 27- 27
• Hadidi, Kianoosh; Løvvik, Ole Martin; Norby, Truls Eivind & Gunnæs, Anette Eleonora (2012). Atomistic study of interfaces in the anode electrode of proton conducting fuel cells.
• Holmestad, Randi; Walmsley, John Charles; Prytz, Øystein; Soleim, Bjørn Gunnar; Van Helvoort, Antonius; Olsen, Arne; Gunnæs, Anette Eleonora; Bjørge, Ruben; Sæterli, Ragnhild; Taftø, Johan; Solberg, Jan Ketil; Vullum, Per Erik; Marioara, Calin Daniel; Yu, Yingda; Thørgersen, A.; Rodenwald, M.; Bergius, M. & Lázár, A. (2012). NORTEM – ambitions and plans.
• Qureishy, Thomas; Hansen, Vidar; Karlsen, Ole Bjørn; Gunnæs, Anette Eleonora & Taftø, Johan (2012). Superstructures in Mg2Si1-xSnx.
• Hadidi, Kianoosh; Løvvik, Ole Martin; Norby, Truls & Gunnæs, Anette Eleonora (2010). Atomistic studies of LaNbO4 surfaces and Ni-LaNbO4 interface.
• Hage, Fredrik Sydow; Helgesen, Geir; Gunnæs, Anette Eleonora & Prytz, Øystein (2010). Graphitization of carbon nanocones and nanodiscs.
• Norby, Truls; Fjeld, Harald; Gunnæs, Anette Eleonora; Hadidi, Kianoosh; Kepaptsoglou, Despoina Maria; Løvvik, Ole Martin; Sunding, Martin Fleissner & Toyoura, Kazuaki (2010). Experimental and Computational Studies of Bulk and Interfaces of a Ceramic Proton Conductor at Atomic and Nano Scale.
• stokkan, Therese S.; Gunnæs, Anette Eleonora; Kepaptsoglou, Despoina Maria & Magraso Sola, Anna (2010). Phase segregation in NiO/LaNbO4 composites.
• Sunding, Martin Fleissner; Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Gunnæs, Anette Eleonora & Norby, Truls (2010). Metal-Oxide interfaces in proton conducting fuel cells studied by angle-resolved XPS.
• Fontaine, Marie-Laure; Larring, Yngve; Mei, Sen; Bredesen, Rune; Syvertsen, Guttorm E; Lein, H. L.; Grande, Tor; Sunding, Martin Fleissner; Kepaptsoglou, Despoina Maria; Diplas, Spyridon; Gunnæs, Anette Eleonora; Løvvik, Ole Martin; Olsen, Arne; Magraso Sola, Anna; Skilbred, Anders Werner Bredvei; Haugsrud, Reidar & Norby, Truls (2009). Proton Conducting SOFCs – From Fundamental Understanding to Fuel Cell Stacks.
• Helgesen, Geir; Knudsen, K.D.; Skjeltorp, Arne Torbjørn; Knaapila, M.; Pinheiro, J.P.; Bourgeaux, M.; Heiberg-Andersen, H.; Gunnæs, Anette Eleonora & Prytz, Øystein (2009). The structure and properties of carbon cones.
• Diplas, Spyridon; Løvvik, Ole Martin; Nordmark, Heidi; Kepaptsoglou, Despoina Maria; Graff, Joachim Moe & Gunnæs, Anette Eleonora (2009). Characterisation of transparent conducting oxide (TCO) films and TCO-Si interfaces with XPS, TEM and ab-initio modelling.
• Gunnæs, Anette Eleonora; Prytz, Øystein; Olsen, Arne; Helgesen, Geir & Knudsen, K. D. (2009). Structural study of C-cones and discs by use of analytical TEM.
• Hage, Frefrik Sydow; Gunnæs, Anette Eleonora; Olsen, Arne & Magraso Sola, Anna (2009). A structural study of lanthanum tungstate by CBED.
• Prytz, Øystein; Gunnæs, Anette Eleonora; Breivik, Tallak Harald; Toberer, E. S.; Snyder, G. J. & Taftø, Johan (2009). Nanostructured thermoelectric materials, reduction of thermal conductivity in Zn4Sb3.
• Klinge, Randi Furseth; Dean, MC; Risnes, Steinar; Erambert, Muriel & Gunnæs, Anette Eleonora (2008). Further observations on the microscopic structure and mineral distribution in tooth and periodontal tissues in an australopithecine fossil hominid from Koobi Fora, Kenya.
• Prytz, Øystein; Gunnæs, Anette Eleonora; Breivik, Tallak Harald; Toberer, Eric; Snyder, Jeff & Taftø, Johan (2008). Transmission Electron Microscopy Studies of Nanostructure in ß-Zn4Sb3.
• Prytz, Øystein; Gunnæs, Anette Eleonora; Toberer, Eric; Snyder, Jeff & Taftø, Johan (2008). Transmission electron microscopy search for defects and disorder causing the low thermal conductivity of Zn4Sb3.
• Diplas, Spyridon; Ulyashin, Alexander; Maknys, Kestutis; Gunnæs, Anette Eleonora; Jørgensen, Sissel; Watts, J.F.; Olsen, Arne & Finstad, Terje (2006). On the processing-structure properties of ITO layers deposited on crystalline and amorphous Si.
• Ulyashin, A. G.; Bentzen, Andreas; Diplas, Spyridon; Gunnæs, Anette Eleonora; Olsen, Arne; Svensson, Bengt Gunnar; Suphellen, Aina; Marstein, E. S.; Holt, A; Grambole, Dieter & Sauar, Erik (2006). Hydrogen release and defect formation during heat treatments of SiNx:H/a-Si:H double passivation layer on c-Si substrate.
• Heng, Chenglin; Finstad, Terje; Li, Yanjun; Mayandi, Jeyanthinath; Jørgensen, Sissel; Storås, Preben; Olsen, Arne & Gunnæs, Anette Eleonora (2005). The precipitation of Ge-rich nano particles in an (Er,Ge) co doped SiO2 matrix.
• Heng, Chenglin; Finstad, Terje; Storås, Preben; Li, Yanjun & Gunnæs, Anette Eleonora (2005). Photoluminescence from an Er- and Ge-doped SiO2 films: The inpluence of sputter gas and annealing.
• Heng, Chenglin; Finstad, Terje; Storås, Preben; Gunnæs, Anette Eleonora & Li, Yanjun (2004). The influence of sputter gas and annealing on photoluminescence and Ge nanoparticle formation in SiO2 films doped with Er.
• Kartopu, G; Ekinci, Y; Serincan, U.; Bayliss, S. C.; Turan, Rasit; Gunnæs, Anette Eleonora & Finstad, Terje (2004). Can porous Ge or Ge nanocrystals emit visible photoluminescence?.
• Turan, Rasit; Serincan, U.; Gunnæs, Anette Eleonora & Finstad, Terje (2004). STRUCTURAL AND OPTICAL PROPERTIES OF SEMICONDUCTOR NANOCRYSTALS EMBEDDED IN SiO2 MATRIX BY ION IMPLANTATION.
• Gunnæs, Anette Eleonora (2003). Solving materials problems with EM.
• Jahren, Jens; Sørbrøden, Erik; Gunnæs, Anette Eleonora; Taftø, Johan & Aagaard, Per (2003). SEM, TEM and EELS of Fe-hydroxide from the Langøya gypsum landfill.
• Knutsen, Turid; Hansen, Vidar; Håkansson, B.; Gunnæs, Anette Eleonora; Jørgensen, Sissel; Våland, T. & Taftø, Johan (2003). A study of amorphous and crystalline Ni78Si8B14.

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