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  • 1.
    Besharat, Zahra
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Adsorption of molecular thin films on metal and metal oxide surfaces2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Metal and metal oxides are widely used in industry, and to optimize their performance their surfaces are commonly functionalized by the formation of thin films. Self-assembled monolayers (SAMs) are deposited on metals or metal oxides either from solution or by gas deposition. Thiols with polar terminal groups are utilized for creating the responsive surfaces which can interact electrostatically with other adsorbates. Surface charge effects wetting and adhesion, and many other surface properties. Polar terminal groups in thiols could be used to modify these factors. Mixed SAMs can provide more flexible surfaces, and could change the resulting surface properties under the influence of factors such as pH, temperature, and photo-illumination. Therefore, in order to control these phenomena by mixed polar-terminated thiols, it is necessary to understand the composition and conformation of the mixed SAMs and their response to these factors. In this work, mixtures of thiols with carboxylic and amino terminal groups were studied. Carboxylic and amino terminal groups of thiol interact with each other via hydrogen bonding in solution and form a complex. Complexes adsorb to the surface in non-conventional orientations. Unmixed SAMs from each type, either carboxylic terminated thiols or amino terminated thiols are in standing up orientation while SAMs from complexes are in an axially in-plane orientation. Selenol is an alternative to replace thiols for particular applications such as contact with biological matter which has a better compatibility with selenol than sulfur. However, the    Se-C bond is weaker than the S-C bond which limits the application of selenol. Understanding the selenol adsorption mechanism on gold surfaces could shed some light on Se-C cleavage and so is investigated in this work. Se-C cleavage happens in the low coverage areas on the step since atoms at steps have lower coordination making them more reactive than atoms on the terraces.  Another area where the self-assembly of molecules is of importance is for dye sensitized solar cells, which are based on the adsorption of the dye onto metal oxides surfaces such as TiO2.The interface between the SAM of dye and the substrate is an important factor to consider when designing dyes and surfaces in dye sensitized solar cells (DSSCs). The quality of the self-assembled monolayers of the dye on the TiO2 surface has a critical influence on the efficiency of the DSSCs.  Creation of just a monolayer of dye on the surface could lead to an efficient current of photo-excited electrons to the TiO2 and degeneration of the dye by redox. This work, T-PAC dye showed island growth with some ad-layer that is not in contact with the surface, whereas the MP13 dye adsorption is laminar growth.  Cuprite (Cu2O) is the initial and most common corrosion product for copper under atmospheric conditions. Copper could be a good replacement for noble metal as catalysts for methanol dehydrogenation. Knowledge about the structure of Cu2O(100) and Cu2O(111) surfaces could be used to obtain a deeper understanding of methanol dehydrogenation mechanisms with respect to adsorption sites on the surfaces. In this work, a detailed study was done of Cu2O(100) surface which revealed the possible surface structures as the result of different preparation conditions. Studies of the structure of Cu2O(100) and Cu2O(111) surfaces show that Cu2O(100) has a comparatively stable surface and reduces surface reactivity. As a consequence, dehydrogenation of methanol is more efficient on the Cu2O(111) surface. The hydrogen produced from methanol dehydrogenation is stored in oxygen adatom sites on both surfaces.

     

  • 2.
    Besharat, Zahra
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF. KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Alvarez-Asencio, Ruben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tian, H.
    Yu, S.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Gothelid, M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    In-situ evaluation of dye adsorption on TiO2 using QCM2017Inngår i: EPJ Photovoltaics, ISSN 2105-0716, Vol. 8, artikkel-id 80401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We measured the adsorption characteristics of two organic dyes; triphenylamine-cyanoacrylic acid (TPA-C) and phenoxazine (MP13), on TiO2, directly in a solution based on quartz crystal microbalance (QCM). Monitoring the adsorbed amount as a function of dye concentration and during rinsing allows determination of the equilibrium constant and distinction between chemisorbed and physisorbed dye. The measured equilibrium constants are 0.8 mM(-1) for TPA-C and 2.4 mM(-1) for MP13. X-ray photoelectron spectroscopy was used to compare dried chemisorbed layers of TPA-C prepared in solution with TPA-C layers prepared via vacuum sublimation; the two preparation methods render similar spectra except a small contribution of water residues (OH) on the solution prepared samples. Quantitative Nanomechanical Mapping Atomic Force Microscopy (QNM-AFM) shows that physisorbed TPA-C layers are easily removed by scanning the tip across the surface. Although not obvious in height images, adhesion images clearly demonstrate removal of the dye.

  • 3.
    Besharat, Zahra
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF. KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ghadami Yazdi, Milad
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Wakeham, Deborah
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    SP Technical Research Institute of Sweden, Sweden.
    Göthelid, Mats
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Grönbeck, Henrik
    Se-C Cleavage of Hexane Selenol at Steps on Au(111)2018Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, nr 8, s. 2630-2636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Selenols are considered as an alternative to thiols in self-assembled monolayers, but the Se-C bond is one limiting factor for their usefulness. In this study, we address the stability of the Se-C bond by a combined experimental and theoretical investigation of gas phase-deposited hexane selenol (CH3(CH2)(5)SeH) on Au(111) using photoelectron spectroscopy, scanning tunneling microscopy, and density functional theory (DFT). Experimentally, we find that initial adsorption leaves atomic Se on the surface without any carbon left on the surface, whereas further adsorption generates a saturated selenolate layer. The Se 3d component from atomic Se appears at 0.85 eV lower binding energy than the selenolate-related component. DFT calculations show that the most stable structure of selenols on Au(111) is in the form of RSe-Au-SeR complexes adsorbed on the unreconstructed Au(111) surface. This is similar to thiols on Au(111). Calculated Se 3d core-level shifts between elemental Se and selenolate in this structure nicely reproduce the experimentally recorded shifts. Dissociation of RSeH and subsequent formation of RH are found to proceed with high barriers on defect-free Au(111) terraces, with the highest barrier for scissoring R-Se. However, at steps, these barriers are considerably lower, allowing for Se-C bond breaking and hexane desorption, leaving elemental Se at the surface. Hexane is the selenol to selenolate formed by replacing the Se-C bond with a H-C bond by using the hydrogen liberated from transformation.

  • 4.
    Besharat, Zahra
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Alvarez Asencio, Ruben.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tian, Haining
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Yu, Shun
    In-situ evaluation of dye adsorption on TiO2 using QCMManuskript (preprint) (Annet vitenskapelig)
  • 5.
    Besharat, Zahra
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Soldemo, Markus
    Halldin Stenlid, Joakim
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Önsten, Anneli
    Weissenrieder, Jonas
    Brinck, Tore
    Dehydrogenation of methanol on Cu2O(100) and (111)Manuskript (preprint) (Annet vitenskapelig)
  • 6.
    Besharat, Zahra
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Wakeham, Deborah
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ghadami Yazdi, Milad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Se-C cleavage of hexane selenol at steps on Au(111)Manuskript (preprint) (Annet vitenskapelig)
  • 7.
    Besharat, Zahra
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF. KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Halldin Stenlid, Joakim
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Soldemo, Markus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Marks, Kess
    Önsten, Anneli
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Öström, Henrik
    Weissenrieder, Jonas
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Brinck, Tore
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Göthelid, Mats
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Materialfysik, MF.
    Dehydrogenation of methanol on Cu2O(100) and (111)2017Inngår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 146, nr 24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adsorption and desorption of methanol on the (111) and (100) surfaces of  Cu2O have been studied using high-resolution photoelectron spectroscopy in the temperature range 120–620 K, in combination with density functional theorycalculations and sum frequency generation spectroscopy. The bare (100) surfaceexhibits a (3,0; 1,1) reconstruction but restructures during the adsorption process into a Cu-dimer geometry stabilized by methoxy and hydrogen binding in Cu-bridge sites. During the restructuring process, oxygen atoms from the bulk that can host hydrogen appear on the surface. Heating transforms methoxy to formaldehyde, but further dehydrogenation is limited by the stability of the surface and the limited access to surface oxygen. The (√3 × √3)R30°-reconstructed (111) surface is based on ordered surface oxygen and copper ions and vacancies, which offers a palette of adsorption and reaction sites. Already at 140 K, a mixed layer of methoxy, formaldehyde, and CHxOy is formed. Heating to room temperature leaves OCH and CHx. Thus both CH-bond breaking and CO-scission are active on this  surface at low temperature. The higher ability to dehydrogenate methanol on (111) compared to (100) is explained by the multitude of adsorption sites and, in particular, the availability of surfaceoxygen.

  • 8.
    Besharat, Zahra
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Wakeham, Deborah
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Odnevall Wallinder, Inger
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Mixed monolayers of alkane thiols with polar terminal group on gold: Investigation of structure dependent surface properties2016Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 484, nr 279, s. 279-290, artikkel-id j.jcis.2016.08.053Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adsorption of thiols with cationic or anionic terminal group on gold has been studied from mixed solutions of 11-Amino-1-undecanethiol (AUT) and 3-Mercaptopropionic acid (MPA) using Quartz Crystal Microbalance with Dissipation (QCM-D), X-ray Photoelectron Spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The goal is to probe the nature of such layers, and the additivity or otherwise of the pH responsiveness, with a view to evaluate their suitability as smart materials. For each of the two pure (unmixed) cases, ordered molecular monolayers are formed with sulfur binding to gold and the alkane chain pointing out from the surface as expected. Adsorption from the thiol mixtures, however, leads to a more complex behaviour. The surface concentration of thiols from the mixtures, as determined by QCM-D, is considerably lower than for the pure cases and it reaches a minimum at a 3:1 MPA/AUT relative concentration in the solution. The XPS results confirm a reduction in adsorbed amount in mixtures with the lowest overall intensity for the 3:1 ratio. Monolayers formed from mixtures display a wettability which is much lower and less pH sensitive. Collectively these results confirm that for adsorption from mixed systems, the configuration is completely different. Complex formation in the mixed solutions leads to the adsorption of molecules parallel to the surface in an axially in-plane configuration. This parallel layer of thiols is mechanically relatively robust to nano-shaving based on AFM measurements. These results will have a significant impact on the design of biomimetic surface coatings particularly when mixtures of oppositely charged molecules are present on the surface, as is commonly the case in biological, proteinaceous surfaces (e.g. hair and skin).

  • 9.
    Kanerva, M.
    et al.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland.;Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Besharat, Zahra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Parnanen, T.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Jokinen, J.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Honkanen, M.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Sarlin, E.
    Tampere Univ, Fac Engn & Nat Sci, POB 589, FI-33014 Tampere, Finland..
    Göthelid, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Schlenzka, D.
    Orton Orthopaed Hosp, FI-00280 Helsinki, Finland.;Res Inst Orton, FI-00280 Helsinki, Finland..
    Miniature CoCr laser welds under cyclic shear: Fatigue evolution and crack growth2019Inngår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 99, s. 93-103Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Miniature laser welds with the root depth in the range of 50-300 pm represent air-tight joints between the components in medical devices, such as those in implants, growth rods, stents and various prostheses. The current work focuses on the development of a fatigue test specimen and procedure to determine fatigue lives of shear-loaded laser welds. A cobalt-chromium (CoCr) alloy is used as a benchmark case. S-N graphs, damage process, and fracture surfaces are studied by applying x-ray analysis, atomic force microscopy, and scanning electron microscopy both before and after the crack onset. A non-linear material model is fitted for the CoCr alloy to run finite element simulations of the damage and deformation. As a result, two tensile-loaded specimen designs are established and the performance is compared to that of a traditional torque-loaded specimen. The new generation specimens show less variation in the determined fatigue lives due to well-defined crack onset point and, therefore, precise weld seam load during the experiments. The fatigue damage concentrates to the welded material and the entire weld experiences fatigue prior to the final, fracture-governed failure phase. For the studied weld seams of hardened CoCr, a regression fatigue limit of 10.8-11.8 MPa, where the stress refers to the arithmetic average shear stress computed along the region dominated by shear loading, is determined.

  • 10.
    Kanerva, M.
    et al.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland. Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Besharat, Zahra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pärnänen, T.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Jokinen, J.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Honkanen, M.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Sarlin, E.
    Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, Tampere, FI-33014, Finland.
    Göthelid, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Schlenzka, D.
    Orton Orthopaedic Hospital and Research Institute Orton, Helsinki, FI-00280, Finland.
    Automatization and stress analysis data of CoCr laser weld fatigue tests2019Inngår i: Data in Brief, E-ISSN 2352-3409, Vol. 26, artikkel-id 104374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work includes raw and analyzed test data when using a recently developed fatigue test method for miniature laser welds in cobalt-chromium (CoCr) alloy joints [1]: 10.1016/j.jmbbm.2019.07.004. The automization of fatigue tests is crucial for saving costs and personnel resources and that is the reason why the atomization threshold and the resulting spectrum data related to CoCr welds are provided here. The finite element method based stress computation output is provided related to shearing-mode tests to support the dataset as a whole. In addition, the compositional data of the parent material and the laser weld are given.

  • 11. Kanerva, Mikko
    et al.
    Besharat, Zahra
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Livingston, Ryan
    Hallila, Harri
    Rutland, Mark
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Plasticity effects during the 4-point bending of intramedullary leg lengthening implants with telescopic structures2015Inngår i: M2D2015: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON MECHANICS AND MATERIALS IN DESIGN, INEGI-FEUP , 2015, s. 893-904Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A telescopic intramedullary leg lengthening implant during standard (ASTM F1264) four-point bend testing is analysed in this study. The structure of a telescopic implant is simulated using different finite element models in order to understand the ultimate bending behaviour. The surface morphology on the internal contact surfaces is also analysed using scanning electron microscopy and atomic force microscopy. The results show that the simulation of correct non-linear behaviour necessitates plastic material models and representative contacts between nested parts. Based on the microscopy analysis, the damage on the contact surfaces inside the locking mechanism of a real tested implant is not found critical in terms of probable crack nucleation sites.

  • 12.
    Marks, Kess
    et al.
    Stockholm Univ, Dept Phys, Chem Phys, SE-10691 Stockholm, Sweden..
    Besharat, Zahra
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Soldemo, Markus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Önsten, Anneli
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Weissenrieder, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Stenlid, Joakim Halldin
    Stockholm Univ, Dept Phys, Chem Phys, SE-10691 Stockholm, Sweden..
    Öström, Henrik
    Stockholm Univ, Dept Phys, Chem Phys, SE-10691 Stockholm, Sweden..
    Göthelid, Mats
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Adsorption and Decomposition of Ethanol on Cu2O(111) and (100)2019Inngår i: JOURNAL OF PHYSICAL CHEMISTRY C, Vol. 123, nr 33, s. 20384-20392Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ethanol dehydrogenation on metal oxides such as Cu2O is an important reaction for the production of renewable energy by fuel cells both via the production of H-2 fuel and via application in direct alcohol fuel cells. To better understand this reaction, we studied the adsorption, dissociation, and desorption of ethanol on Cu2O(111) and (100) surfaces using high-resolution photoelectron spectroscopy, vibrational sum-frequency generation spectroscopy, and temperature-programmed desorption accompanied by density functional theory calculations. On Cu-2(100), the first layer consists primarily of dissociatively adsorbed ethoxy. Second and third layers of ethanol physisorb at low temperatures and desorb below 200 K. On the Cu2O(111) surface, adsorption is mixed as ethoxy, ethanol, and the products following C-C cleavage, CHx, and OCHx, are found in the first layer. Upon heating, products following both C-C and C-O bond breaking are observed on both surfaces and continued heating accentuates molecular cracking. C-O cleavage occurs more on the (100) surface, whereas on the Cu2O(111) surface, C-C cleavage dominates and occurs at lower temperatures than those for the (100) surface. The increased ability of Cu2O(111) to crack ethanol is explained by the varied surface structure including surface oxygen, electron-rich O vacancies, and Cu.

  • 13. Rihtnesberg, D. B.
    et al.
    Almqvist, S.
    Wang, Q.
    Sugunan, Abhilash
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Funktionella material, FNM (Stängd 20120101).
    Yang, Xuran
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Funktionella material, FNM (Stängd 20120101).
    Toprak, Muhammet
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Funktionella material, FNM (Stängd 20120101).
    Besharat, Zahra
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Funktionella material, FNM (Stängd 20120101).
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Materialfysik, MF (Stängd 20120101).
    ZnO nanorods/nanoflowers and their applications2011Inngår i: Proc. - Int. NanoElectronics Conf., INEC, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Single-crystalline zinc oxide (ZnO) nanorods (NRs) have been synthesized through a chemical bath deposition method. Their diameter is about 80 nm, and their length range from 1 μm to 7 μm can be controlled by growth time. Formation of nanoflower arrays composed of nanorods has been also achieved utilizing a standard micro-fabrication technique. Two types of ZnO nanorods devices are detailed to demonstrate their optoelectronic applications.

  • 14.
    Soldemo, Markus
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Halldin Stenlid, Joakim
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Besharat, Zahra
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Ghadami Yazdi, Milad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Önsten, Anneli
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Brinck, Tore
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Weissenrieder, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    The Surface Structure of Cu2O(100)2016Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, nr 8, s. 4373-4381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite the industrial importance of copper oxides, the nature of the (100) surface of Cu2O has remained poorly understood. The surface has previously been subject to several theoretical and experimental studies, but has until now not been investigated by atomically resolved microscopy or high-resolution photoelectron spectroscopy. Here we determine the atomic structure and electronic properties of Cu2O(100) by a combination of multiple experimental techniques and simulations within the framework of density functional theory (DFT). Low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) characterized the three ordered surface structures found. From DFT calculations, the structures are found to be energetically ordered as (3,0;1,1), c(2 x 2), and (1 x 1) under ultrahigh vacuum conditions. Increased oxygen pressures induce the formation of an oxygen terminated (1 x 1) surface structure. The most common termination of Cu2O(100) has previously been described by a (3 root 2 x root 2)R45 degrees unit cell exhibiting a LEED pattern with several missing spots. Through atomically resolved STM, we show that this structure instead is described by the matrix (3,0;1,1). Both simulated STM images and calculated photoemission core level shifts compare favorably with the experimental results.

  • 15.
    Soldemo, Markus
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Johansson, Niclas
    Besharat, Zahra
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Önsten, Anneli
    Göthelid, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Knudsen, Jan
    Schnadt, Joachim
    Weissenrieder, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Cuprous oxide surfaces exposed to sulfur dioxide and near-ambient pressures of waterManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The interaction of sulfur dioxide with Cu2O(100) and Cu2O(111) at ultra-high vac-uum is studied. It is found that on both surfaces, the sulfur dioxide moleculesbind as SO3-species. Dosing water in UHV does not impact the SO3-species at thedoses used. When dosing water at near-ambient pressure conditions, however, itis observed that the sulfur in the SO3-species shifts to Cu2S when monitoring thePES S 2p-region.

1 - 15 of 15
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