1
|
Sahu R, Bogdanovski D, Achenbach JO, Hans M, Primetzhofer D, Schneider JM, Scheu C. Compositional defects in a MoAlB MAB phase thin film grown by high-power pulsed magnetron sputtering. Nanoscale 2023; 15:17356-17363. [PMID: 37876283 DOI: 10.1039/d3nr04233b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Various compositional defects such as Mo3Al2B4, Mo4Al3B4, Mo6Al5B6 and Al3Mo, together with MoB MBene, are observed to be coexisting in a MoAlB MAB phase thin film grown at 800 °C by high-power pulsed magnetron sputtering. An overall film composition of Mo0.29Al0.33B0.38 is measured by time-of-flight elastic recoil detection analysis. The concurrent formation of these compositional defects in the MoAlB matrix occurs during the synthesis without using any chemical reagent, and their coexistence with the MAB phase is thermodynamically possible, as elucidated by density functional theory simulations. These defect phases are imaged at the atomic scale by aberration-corrected scanning transmission electron microscopy. A rough estimation of defect populations of 0.073, 0.037, 0.042 and 0.039 nm-1 for Mo3Al2B4, Mo4Al3B4, Mo6Al5B6 and Al3Mo compositional defects, respectively, is performed within the MoAlB matrix. The calculated energies of formation reveal that the Mo4Al3B4 and Mo6Al5B6 defect phases form spontaneously in the MoAlB host matrix, while the energy barrier towards the formation of the metastable Mo3Al2B4 phase is approx. 20 meV per atom. The small magnitude of this barrier is easily overcome during vapor phase condensation, and the surface diffusion of adatoms during deposition leads to local compositional variations and the coexistence of the defect phases in the host matrix. Additionally, at grain boundaries, the presence of MoB MBene is observed, with an interlayer spacing between two Mo2B2 units increasing up to ∼50% compared to the pristine MoAlB phase.
Collapse
Affiliation(s)
- Rajib Sahu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany.
| | - Dimitri Bogdanovski
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany.
| | - Jan-Ole Achenbach
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany.
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany.
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Jochen M Schneider
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany.
| | - Christina Scheu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Analytics, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| |
Collapse
|
2
|
Waldl H, Hans M, Schiester M, Primetzhofer D, Burtscher M, Schalk N, Tkadletz M. Decomposition of CrN induced by laser-assisted atom probe tomography. Ultramicroscopy 2023; 246:113673. [PMID: 36610317 DOI: 10.1016/j.ultramic.2022.113673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
It is known that measurement parameters can significantly influence the elemental composition determined by atom probe tomography (APT). Especially results obtained by laser-assisted APT show a strong effect of the laser pulse energy on the apparent elemental composition. Within this study laser-assisted APT experiments were performed on Cr0.51N0.49 and thermally more stable (Cr0.47Al0.53)0.49N0.51, comparing two different base temperatures (i.e. 15 and 60 K), laser wavelengths (i.e. 532 and 355 nm) and systematically modified laser pulse energies. Absolute chemical compositions from laser-assisted APT were compared to data obtained from ion beam analysis. The deduced elemental composition of CrN exhibited a strong increase of the Cr content when the laser pulse energy was increased for both laser wavelengths. For low laser pulse energies Cr, CrN, N and N2 ions were identified, while the amount of detected Cr ions increased and the amount of N ions strongly decreased at higher laser pulse energies. Further, increased detection of more complex Cr-containing ions such as Cr2N at the expense of CrN was observed at higher pulse energies. At the highest pulse energy levels used within this work, the resulting Cr content was > 80 at%, dominated by the amount of detected elemental Cr ions. The change of the mass spectrum of the detected ions with increasing laser pulse energy provides evidence that high laser pulse energies initiate the decomposition of CrN during the APT measurement, consistent with the known thermal decomposition path into Cr2N and subsequently into Cr and gaseous N. In contrast, variation of the laser pulse energy for the thermally more stable CrAlN resulted only in a slight increase of Cr and a decrease of the resulting concentrations of Al and N with increasing laser pulse energy and no change in the type of detected ions. In conclusion, within the present study, the decomposition of a coating material with low thermal stability induced by laser-assisted APT was reported for the first time, emphasizing the importance of the selection of suitable measurement parameters for metastable materials, which are prone to thermal decomposition.
Collapse
Affiliation(s)
- Helene Waldl
- Christian Doppler Laboratory for Advanced Coated Cutting Tools, Montanuniversität Leoben, Franz Josef-Straße 18, 8700 Leoben, Austria.
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, 52074 Aachen, Germany
| | - Maximilian Schiester
- Department of Materials Science, Montanuniversität Leoben, Franz Josef-Straße 18, 8700 Leoben, Austria
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Michael Burtscher
- Department of Materials Science, Chair of Materials Physics, Montanuniversität Leoben, 8700 Leoben, Austria
| | - Nina Schalk
- Christian Doppler Laboratory for Advanced Coated Cutting Tools, Montanuniversität Leoben, Franz Josef-Straße 18, 8700 Leoben, Austria
| | - Michael Tkadletz
- Department of Materials Science, Montanuniversität Leoben, Franz Josef-Straße 18, 8700 Leoben, Austria
| |
Collapse
|
3
|
Moldarev D, Komander K, Holeňák R, Wolff M, Primetzhofer D. A new setup for optical measurements under controlled environment. Rev Sci Instrum 2023; 94:035104. [PMID: 37012801 DOI: 10.1063/5.0142068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/10/2023] [Indexed: 06/19/2023]
Abstract
We present a new analytical instrument for studying the optical properties of materials in different gaseous environments at room and controlled elevated temperatures. The system consists of a vacuum chamber, which is equipped with temperature and pressure controllers, a heating band, and a residual gas analyzer and is connected to a gas feeding line via a leak valve. Two transparent view ports located around a sample holder allow for optical transmission and pump-probe spectroscopy using an external optical setup. The capabilities of the setup are demonstrated by conducting two experiments. In the first experiment, we study the photodarkening and bleaching kinetics of photochromic oxygen-containing yttrium hydride thin films illuminated in ultra high-vacuum and correlate it with changes in partial pressures inside the vacuum chamber. In the second study, we investigate changes in the optical properties of a 50 nm V film upon hydrogen absorption.
Collapse
Affiliation(s)
- Dmitrii Moldarev
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Kristina Komander
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Radek Holeňák
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Max Wolff
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| |
Collapse
|
4
|
Niiranen P, Nadhom H, Zanáška M, Boyd R, Sortica M, Primetzhofer D, Lundin D, Pedersen H. Biased quartz crystal microbalance method for studies of chemical vapor deposition surface chemistry induced by plasma electrons. Rev Sci Instrum 2023; 94:023902. [PMID: 36859015 DOI: 10.1063/5.0122143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
A recently presented chemical vapor deposition (CVD) method involves using plasma electrons as reducing agents for deposition of metals. The plasma electrons are attracted to the substrate surface by a positive substrate bias. Here, we present how a standard quartz crystal microbalance (QCM) system can be modified to allow applying a DC bias to the QCM sensor to attract plasma electrons to it and thereby also enable in situ growth monitoring during the electron-assisted CVD method. We show initial results from mass gain evolution over time during deposition of iron films using the biased QCM and how the biased QCM can be used for process development and provide insight into the surface chemistry by time-resolving the CVD method. Post-deposition analyses of the QCM crystals by cross-section electron microscopy and high-resolution x-ray photoelectron spectroscopy show that the QCM crystals are coated by an iron-containing film and thus function as substrates in the CVD process. A comparison of the areal mass density given by the QCM crystal and the areal mass density from elastic recoil detection analysis and Rutherford backscattering spectrometry was done to verify the function of the QCM setup. Time-resolved CVD experiments show that this biased QCM method holds great promise as one of the tools for understanding the surface chemistry of the newly developed CVD method.
Collapse
Affiliation(s)
- Pentti Niiranen
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Hama Nadhom
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Michal Zanáška
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Robert Boyd
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Mauricio Sortica
- Department of Physics and Astronomy, Uppsala University, Box 529, SE-751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 529, SE-751 20 Uppsala, Sweden
| | - Daniel Lundin
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Henrik Pedersen
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
| |
Collapse
|
5
|
Aliramaji S, Keuter P, Neuß D, Hans M, Primetzhofer D, Depla D, Schneider JM. Effect of Growth Temperature and Atmosphere Exposure Time on Impurity Incorporation in Sputtered Mg, Al, and Ca Thin Films. Materials (Basel) 2023; 16:414. [PMID: 36614754 PMCID: PMC9822154 DOI: 10.3390/ma16010414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Impurities can be incorporated during thin film deposition, but also can originate from atmosphere exposure. As impurities can strongly affect the composition-structure-property relations in magnetron sputter deposited thin films, it is important to distinguish between both incorporation channels. Therefore, the impurity incorporation by atmosphere exposure into sputtered Mg, Al, and Ca thin films is systematically studied by a variation of the deposition temperatures and atmosphere exposure times. Deposition temperature variation results in morphological modifications explained by considering surface and bulk diffusion as well as grain boundary motion and evaporation. The film morphologies exhibiting the lowest oxygen concentrations, as measured by energy dispersive X-ray spectroscopy, are obtained at a homologous temperature of 0.4 for both Mg and Al thin films. For Ca, preventing atmosphere exposure is essential to hinder impurity incorporation: By comparing the impurity concentration in Al-capped and uncapped thin films, it is demonstrated that Ca thin films are locally protected by Al-capping, while Mg (and Al) form native passivation layers. Furthermore, it can be learned that the capping (or self-passivation) efficiency in terms of hindering further oxidation of the films in atmosphere is strongly dependent on the underlying morphology, which in turn is defined by the growth temperature.
Collapse
Affiliation(s)
- Shamsa Aliramaji
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | - Philipp Keuter
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | - Deborah Neuß
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Diederik Depla
- Department of Solid State Sciences, Ghent University, Krijgslaan 281 (S1), B-9000 Gent, Belgium
| | - Jochen M. Schneider
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| |
Collapse
|
6
|
Cupak C, Pitthan E, Moro M, Fellinger M, Primetzhofer D, Aumayr F. Retention of deuterium in beryllium: A combined investigation using TDS, ERDA and EBS. Nuclear Materials and Energy 2022. [DOI: 10.1016/j.nme.2022.101249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
7
|
Zhu Y, Liang JS, Mathayan V, Nyberg T, Primetzhofer D, Shi X, Zhang Z. High Performance Full-Inorganic Flexible Memristor with Combined Resistance-Switching. ACS Appl Mater Interfaces 2022; 14:21173-21180. [PMID: 35477302 PMCID: PMC9100493 DOI: 10.1021/acsami.2c02264] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 04/15/2022] [Indexed: 06/02/2023]
Abstract
Flexible memristors hold great promise for flexible electronics applications but are still lacking of good electrical performance together with mechanical flexibility. Herein, we demonstrate a full-inorganic nanoscale flexible memristor by using free-standing ductile α-Ag2S films as both a flexible substrate and a functional electrolyte. The device accesses dense multiple-level nonvolatile states with a record high 106 ON/OFF ratio. This exceptional memristor performance is induced by sequential processes of Schottky barrier modification at the contact interface and filament formation inside the electrolyte. In addition, it is crucial to ensure that the cathode junction, where Ag+ is reduced to Ag, dominates the total resistance and takes the most of setting bias before the filament formation. Our study provides a comprehensive insight into the resistance-switching mechanism in conductive-bridging memristors and offers a new strategy toward high performance flexible memristors.
Collapse
Affiliation(s)
- Yuan Zhu
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, Uppsala 75121, Sweden
| | - Jia-sheng Liang
- State
Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of
Sciences, Shanghai 200050, China
| | - Vairavel Mathayan
- Department
of Physics and Astronomy, Uppsala University, Uppsala 75121, Sweden
| | - Tomas Nyberg
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, Uppsala 75121, Sweden
| | - Daniel Primetzhofer
- Department
of Physics and Astronomy, Uppsala University, Uppsala 75121, Sweden
| | - Xun Shi
- State
Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of
Sciences, Shanghai 200050, China
| | - Zhen Zhang
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, Uppsala 75121, Sweden
| |
Collapse
|
8
|
Ntemou E, Holeňák R, Primetzhofer D. Energy deposition by H and He ions at keV energies in self-supporting, single crystalline SiC foils. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
9
|
Roeder SS, Burkardt P, Rost F, Rode J, Brusch L, Coras R, Englund E, Håkansson K, Possnert G, Salehpour M, Primetzhofer D, Csiba L, Molnár S, Méhes G, Tonchev AB, Schwab S, Bergmann O, Huttner HB. Evidence for postnatal neurogenesis in the human amygdala. Commun Biol 2022; 5:366. [PMID: 35440676 PMCID: PMC9018740 DOI: 10.1038/s42003-022-03299-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/22/2022] [Indexed: 12/12/2022] Open
Abstract
The human amygdala is involved in processing of memory, decision-making, and emotional responses. Previous studies suggested that the amygdala may represent a neurogenic niche in mammals. By combining two distinct methodological approaches, lipofuscin quantification and 14C-based retrospective birth dating of neurons, along with mathematical modelling, we here explored whether postnatal neurogenesis exists in the human amygdala. We investigated post-mortem samples of twelve neurologically healthy subjects. The average rate of lipofuscin-negative neurons was 3.4%, representing a substantial proportion of cells substantially younger than the individual. Mass spectrometry analysis of genomic 14C-concentrations in amygdala neurons compared with atmospheric 14C-levels provided evidence for postnatal neuronal exchange. Mathematical modelling identified a best-fitting scenario comprising of a quiescent and a renewing neuronal population with an overall renewal rate of >2.7% per year. In conclusion, we provide evidence for postnatal neurogenesis in the human amygdala with cell turnover rates comparable to the hippocampus. Lipofuscin labeling and 14 C retrospective birth-dating of neurons, along with mathematical modelling, here suggest continued postnatal neurogenesis in the human amygdala, rather than protracted maturation of developmentally generated neurons.
Collapse
Affiliation(s)
- Sebastian S Roeder
- Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Petra Burkardt
- Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Fabian Rost
- Center for Regenerative Therapies (CRTD), TU Dresden, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Information Services and High Performance Computing (ZIH), TU Dresden, Dresden, Germany.,Center for Molecular and Cellular Bioengineering, DRESDEN-concept Genome Center, TU Dresden, Dresden, Germany
| | - Julian Rode
- Center for Information Services and High Performance Computing (ZIH), TU Dresden, Dresden, Germany
| | - Lutz Brusch
- Center for Information Services and High Performance Computing (ZIH), TU Dresden, Dresden, Germany
| | - Roland Coras
- Department of Neuropathology, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | - Karl Håkansson
- Tandem Laboratory, Uppsala University, Uppsala, Sweden.,Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | | | - Mehran Salehpour
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Daniel Primetzhofer
- Tandem Laboratory, Uppsala University, Uppsala, Sweden.,Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - László Csiba
- Department of Neurology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Cerebrovascular and Neurodegenerative Research Group, Debrecen, Hungary
| | - Sarolta Molnár
- Department of Pathology, University of Debrecen, Debrecen, Hungary
| | - Gábor Méhes
- Department of Pathology, University of Debrecen, Debrecen, Hungary
| | - Anton B Tonchev
- Departments of Anatomy, Cell Biology and Stem Cell Biology, Medical University Varna, Varna, Bulgaria
| | - Stefan Schwab
- Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Olaf Bergmann
- Center for Regenerative Therapies (CRTD), TU Dresden, Dresden, Germany.,Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Hagen B Huttner
- Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany. .,Department of Neurology, Justus Liebig University Giessen, Giessen, Germany.
| |
Collapse
|
10
|
Moldarev D, Aracheloff C, Moro MV, Pitthan E, Wolff M, Primetzhofer D. Oxygen mobility in yttrium hydride films studied by isotopic labelling. EPJ Web Conf 2022. [DOI: 10.1051/epjconf/202226101001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photochromic properties of oxygen-containing yttrium hydride thin films are directly dependent on the oxygen concentration in the material. We use 16O/18O labelling to study oxidation of YH2 films. Oxygen penetrates the film through grain boundaries and intercolumnar voids oxidising the whole film thickness, without pronounced surface oxidation or self-passivation. Once oxidised, the mobility of oxygen in the films is low and no detectable changes in chemical composition of 18O-labeled YHO films is found under illumination.
Collapse
|
11
|
Wolf PM, Pitthan E, Zhang Z, Lavoie C, Tran TT, Primetzhofer D. Direct Transition from Ultrathin Orthorhombic Dinickel Silicides to Epitaxial Nickel Disilicide Revealed by In Situ Synthesis and Analysis. Small 2022; 18:e2106093. [PMID: 35191181 DOI: 10.1002/smll.202106093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Understanding phase transitions of ultrathin metal silicides is crucial for the development of nanoscale silicon devices. Here, the phase transition of ultrathin (3.6 nm) Ni silicides on Si(100) substrates is investigated using an in situ synthesis and characterization approach, supplemented with ex situ transmission electron microscopy and nano-beam electron diffraction. First, an ultrathin epitaxial layer and ordered structures at the interface are observed upon room-temperature deposition. At 290 °C, this structure is followed by formation of an orthorhombic δ-Ni2 Si phase exhibiting long-range order and extending to the whole film thickness. An unprecedented direct transition from this δ-Ni2 Si phase to the final NiSi2- x phase is observed at 290 °C, skipping the intermediate monosilicide phase. Additionally, the NiSi2- x phase is found epitaxial on the substrate. This transition process substantially differs from observations for thicker films. Furthermore, considering previous studies, the long-range ordered orthorhombic δ-Ni2 Si phase is suggested to occur regardless of the initial Ni thickness. The thickness of this ordered δ-Ni2 Si layer is, however, limited due to the competition of different orientations of the δ-Ni2 Si crystal. Whether the formed δ-Ni2 Si layer consumes all deposited nickel is expected to determine whether the monosilicide phase appears before the transition to the final NiSi2- x phase.
Collapse
Affiliation(s)
- Philipp M Wolf
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Eduardo Pitthan
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Zhen Zhang
- Solid State Electronics, Department of Electrical Engineering, The Ångström Laboratory, Uppsala University, Uppsala, SE-751 21, Sweden
| | - Christian Lavoie
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York, 10598, USA
| | - Tuan T Tran
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| |
Collapse
|
12
|
Steinhoff MK, Holzapfel DM, Karimi Aghda S, Neuß D, Pöllmann PJ, Hans M, Primetzhofer D, Schneider JM, Azina C. Ag Surface and Bulk Segregations in Sputtered ZrCuAlNi Metallic Glass Thin Films. Materials (Basel) 2022; 15:ma15051635. [PMID: 35268865 PMCID: PMC8910967 DOI: 10.3390/ma15051635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/15/2022] [Accepted: 02/18/2022] [Indexed: 02/04/2023]
Abstract
We report on the formation of Ag-containing ZrCuAlNi thin film metallic glass (nano)composites by a hybrid direct-current magnetron sputtering and high-power pulsed magnetron sputtering process. The effects of Ag content, substrate temperature and substrate bias potential on the phase formation and morphology of the nanocomposites were investigated. While applying a substrate bias potential did not strongly affect the morphological evolution of the films, the Ag content dictated the size and distribution of Ag surface segregations. The films deposited at low temperatures were characterized by strong surface segregations, formed by coalescence and Ostwald ripening, while the volume of the films remained featureless. At higher deposition temperature, elongated Ag segregations were observed in the bulk and a continuous Ag layer was formed at the surface as a result of thermally enhanced surface diffusion. While microstructural observations have allowed identifying both surface and bulk segregations, an indirect method for detecting the presence of Ag segregations is proposed, by measuring the electrical resistivity of the films.
Collapse
Affiliation(s)
- Michael K. Steinhoff
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Damian M. Holzapfel
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Soheil Karimi Aghda
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Deborah Neuß
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Peter J. Pöllmann
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Lägerhyddsvägen 1, S-75120 Uppsala, Sweden;
| | - Jochen M. Schneider
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
| | - Clio Azina
- Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, D-52074 Aachen, Germany; (M.K.S.); (D.M.H.); (S.K.A.); (D.N.); (P.J.P.); (M.H.); (J.M.S.)
- Correspondence: ; Tel.: +49-241-8025997
| |
Collapse
|
13
|
Shams-Latifi J, Ström P, Pitthan E, Primetzhofer D. An in-situ ToF-LEIS and AES study of near-surface modifications of the composition of EUROFER97 induced by thermal annealing. Nuclear Materials and Energy 2022. [DOI: 10.1016/j.nme.2022.101139] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
14
|
Pham NH, Yao Y, Wen C, Li S, Zeng S, Nyberg T, Tran TT, Primetzhofer D, Zhang Z, Zhang SL. Self-Limited Formation of Bowl-Shaped Nanopores for Directional DNA Translocation. ACS Nano 2021; 15:17938-17946. [PMID: 34762404 PMCID: PMC8613906 DOI: 10.1021/acsnano.1c06321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Solid-state nanopores of on-demand dimensions and shape can facilitate desired sensor functions. However, reproducible fabrication of arrayed nanopores of predefined dimensions remains challenging despite numerous techniques explored. Here, bowl-shaped nanopores combining properties of ultrathin membrane and tapering geometry are manufactured using a self-limiting process developed on the basis of standard silicon technology. The upper opening of the bowl-nanopores is 60-120 nm in diameter, and the bottom orifice reaches sub-5 nm. Current-voltage characteristics of the fabricated bowl-nanopores display insignificant rectification indicating weak ionic selectivity, in accordance to numerical simulations showing minor differences in electric field and ionic velocity upon the reversal of bias voltages. Simulations reveal, concomitantly, high-momentum electroosmotic flow downward along the concave nanopore sidewall. Collisions between the left and right tributaries over the bottom orifice drive the electroosmotic flow both up into the nanopore and down out of the nanopore through the orifice. The resultant asymmetry in electrophoretic-electroosmotic force is considered the cause responsible for the experimentally observed strong directionality in λ-DNA translocation with larger amplitude, longer duration, and higher frequencies for the downward movements from the upper opening than the upward ones from the orifice. Thus, the resourceful silicon nanofabrication technology is shown to enable nanopore designs toward enriching sensor applications.
Collapse
Affiliation(s)
- Ngan Hoang Pham
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Yao Yao
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Chenyu Wen
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Shiyu Li
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Shuangshuang Zeng
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Tomas Nyberg
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Tuan Thien Tran
- Division
of Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Division
of Applied Nuclear Physics, Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Zhen Zhang
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| | - Shi-Li Zhang
- Division
of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, SE-751 03 Uppsala, Sweden
| |
Collapse
|
15
|
Sahu R, Bogdanovski D, Achenbach JO, Zhang S, Hans M, Primetzhofer D, Schneider JM, Scheu C. Direct MoB MBene domain formation in magnetron sputtered MoAlB thin films. Nanoscale 2021; 13:18077-18083. [PMID: 34726227 DOI: 10.1039/d1nr05712j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) inorganic transition metal boride nanosheets are emerging as promising post-graphene materials in energy research due to their unique properties. State-of-the-art processing strategies are based on chemical etching of bulk material synthesized via solid-state reaction at temperatures above 1000 °C. Here, we report the direct formation of MoB MBene domains in a MoAlB thin film by Al deintercalation from MoAlB in the vicinity of AlOx regions. Hence, based on these results a straightforward processing pathway for the direct formation of MoB MBene-AlOx heterostructures without employing chemical etching is proposed here.
Collapse
Affiliation(s)
- Rajib Sahu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| | - Dimitri Bogdanovski
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| | - Jan-Ole Achenbach
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| | - Siyuan Zhang
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Jochen M Schneider
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| | - Christina Scheu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
- Materials Analytics, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany
| |
Collapse
|
16
|
McCarthy BD, Liseev T, Sortica MA, Paneta V, Gschwind W, Nagy G, Ott S, Primetzhofer D. Elemental Depth Profiling of Intact Metal-Organic Framework Single Crystals by Scanning Nuclear Microprobe. J Am Chem Soc 2021; 143:18626-18634. [PMID: 34726402 PMCID: PMC8587607 DOI: 10.1021/jacs.1c08550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The growing field
of MOF–catalyst composites often relies
on postsynthetic modifications for the installation of active sites.
In the resulting MOFs, the spatial distribution of the inserted catalysts
has far-reaching ramifications for the performance of the system and
thus needs to be precisely determined. Herein, we report the application
of a scanning nuclear microprobe for accurate and nondestructive depth
profiling of individual UiO-66 and UiO-67 (UiO = Universitetet i Oslo)
single crystals. Initial optimization work using native UiO-66 crystals
yielded a microbeam method which avoided beam damage, while subsequent
analysis of Zr/Hf mixed-metal UiO-66 crystals demonstrated the potential
of the method to obtain high-resolution depth profiles. The microbeam
method was further used to analyze the depth distribution of postsynthetically
introduced organic moieties, revealing either core–shell or
uniform incorporation can be obtained depending on the size of the
introduced molecule, as well as the number of carboxylate binding
groups. Finally, the spatial distribution of platinum centers that
were postsynthetically installed in the bpy binding pockets of UiO-67-bpy
(bpy = 5,5′-dicarboxyy-2,2′-bipyridine) was analyzed
by microbeam and contextualized. We expect that the method presented
herein will be applicable for characterizing a wide variety of MOFs
subjected to postsynthetic modifications and provide information crucial
for their optimization as functional materials.
Collapse
Affiliation(s)
- Brian D McCarthy
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Timofey Liseev
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | | | - Valentina Paneta
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Wanja Gschwind
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Gyula Nagy
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Sascha Ott
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Tandem Laboratory, Uppsala University, Box 529, 751 20 Uppsala, Sweden.,Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| |
Collapse
|
17
|
Cediel-Ulloa A, Isaxon C, Eriksson A, Primetzhofer D, Sortica MA, Haag L, Derr R, Hendriks G, Löndahl J, Gudmundsson A, Broberg K, Gliga AR. Toxicity of stainless and mild steel particles generated from gas-metal arc welding in primary human small airway epithelial cells. Sci Rep 2021; 11:21846. [PMID: 34750422 PMCID: PMC8575907 DOI: 10.1038/s41598-021-01177-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/21/2021] [Indexed: 11/09/2022] Open
Abstract
Welding fumes induce lung toxicity and are carcinogenic to humans but the molecular mechanisms have yet to be clarified. The aim of this study was to evaluate the toxicity of stainless and mild steel particles generated via gas-metal arc welding using primary human small airway epithelial cells (hSAEC) and ToxTracker reporter murine stem cells, which track activation of six cancer-related pathways. Metal content (Fe, Mn, Ni, Cr) of the particles was relatively homogenous across particle size. The particles were not cytotoxic in reporter stem cells but stainless steel particles activated the Nrf2-dependent oxidative stress pathway. In hSAEC, both particle types induced time- and dose-dependent cytotoxicity, and stainless steel particles also increased generation of reactive oxygen species. The cellular metal content was higher for hSAEC compared to the reporter stem cells exposed to the same nominal dose. This was, in part, related to differences in particle agglomeration/sedimentation in the different cell media. Overall, our study showed differences in cytotoxicity and activation of cancer-related pathways between stainless and mild steel welding particles. Moreover, our data emphasizes the need for careful assessment of the cellular dose when comparing studies using different in vitro models.
Collapse
Affiliation(s)
- Andrea Cediel-Ulloa
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden
- Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Christina Isaxon
- Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
- NanoLund, Lund University, Lund, Sweden
| | - Axel Eriksson
- Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
- NanoLund, Lund University, Lund, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Applied Nuclear Physics, Uppsala University, Uppsala, Sweden
- The Tandem Laboratory, Uppsala University, Uppsala, Sweden
| | | | - Lars Haag
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Jakob Löndahl
- Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
- NanoLund, Lund University, Lund, Sweden
| | - Anders Gudmundsson
- Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
- NanoLund, Lund University, Lund, Sweden
| | - Karin Broberg
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden
| | - Anda R Gliga
- Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
| |
Collapse
|
18
|
Wimmer S, Sánchez-Barriga J, Küppers P, Ney A, Schierle E, Freyse F, Caha O, Michalička J, Liebmann M, Primetzhofer D, Hoffman M, Ernst A, Otrokov MM, Bihlmayer G, Weschke E, Lake B, Chulkov EV, Morgenstern M, Bauer G, Springholz G, Rader O. Mn-Rich MnSb 2 Te 4 : A Topological Insulator with Magnetic Gap Closing at High Curie Temperatures of 45-50 K. Adv Mater 2021; 33:e2102935. [PMID: 34469013 DOI: 10.1002/adma.202102935] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Ferromagnetic topological insulators exhibit the quantum anomalous Hall effect, which is potentially useful for high-precision metrology, edge channel spintronics, and topological qubits. The stable 2+ state of Mn enables intrinsic magnetic topological insulators. MnBi2 Te4 is, however, antiferromagnetic with 25 K Néel temperature and is strongly n-doped. In this work, p-type MnSb2 Te4 , previously considered topologically trivial, is shown to be a ferromagnetic topological insulator for a few percent Mn excess. i) Ferromagnetic hysteresis with record Curie temperature of 45-50 K, ii) out-of-plane magnetic anisotropy, iii) a 2D Dirac cone with the Dirac point close to the Fermi level, iv) out-of-plane spin polarization as revealed by photoelectron spectroscopy, and v) a magnetically induced bandgap closing at the Curie temperature, demonstrated by scanning tunneling spectroscopy (STS), are shown. Moreover, a critical exponent of the magnetization β ≈ 1 is found, indicating the vicinity of a quantum critical point. Ab initio calculations reveal that Mn-Sb site exchange provides the ferromagnetic interlayer coupling and the slight excess of Mn nearly doubles the Curie temperature. Remaining deviations from the ferromagnetic order open the inverted bulk bandgap and render MnSb2 Te4 a robust topological insulator and new benchmark for magnetic topological insulators.
Collapse
Affiliation(s)
- Stefan Wimmer
- Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
| | - Jaime Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Philipp Küppers
- II. Institute of Physics B and JARA-FIT, RWTH Aachen Unversity, 52074, Aachen, Germany
| | - Andreas Ney
- Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
| | - Enrico Schierle
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Friedrich Freyse
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
| | - Ondrej Caha
- Department of Condensed Matter Physics, Masaryk University, Kotlářská 267/2, Brno, 61137, Czech Republic
| | - Jan Michalička
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 612 00, Czech Republic
| | - Marcus Liebmann
- II. Institute of Physics B and JARA-FIT, RWTH Aachen Unversity, 52074, Aachen, Germany
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Universitet Uppsala, Lägerhyddsvägen 1, Uppsala, 75120, Sweden
| | - Martin Hoffman
- Institute for Theoretical Physics, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
| | - Arthur Ernst
- Institute for Theoretical Physics, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Mikhail M Otrokov
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, San Sebastián/Donostia, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48011, Spain
| | - Gustav Bihlmayer
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | - Eugen Weschke
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Bella Lake
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Evgueni V Chulkov
- Donostia International Physics Center (DIPC), San Sebastián/Donostia, 20018, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, San Sebastián/Donostia, 20080, Spain
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
- Tomsk State University, Tomsk, 634050, Russia
| | - Markus Morgenstern
- II. Institute of Physics B and JARA-FIT, RWTH Aachen Unversity, 52074, Aachen, Germany
| | - Günther Bauer
- Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
| | - Gunther Springholz
- Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität, Altenberger Straße 69, Linz, 4040, Austria
| | - Oliver Rader
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| |
Collapse
|
19
|
Komander K, Tran T, Saha J, Moro MV, Pálsson GK, Wolff M, Primetzhofer D. Interstitial Hydrogen in Fe/V Superstructures: Lattice Site Location and Thermal Vibration. Phys Rev Lett 2021; 127:136102. [PMID: 34623839 DOI: 10.1103/physrevlett.127.136102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
We report real space location of hydrogen in single crystalline Fe/V superstructures. Anisotropic strain is quantified versus hydrogen concentration by using the yield of backscattered primary 2 MeV ^{4}He ions for incidence in different crystallographic directions. From a comparison of ion channeling in combination with ^{1}H(^{15}N,αγ)^{12}C nuclear reaction analysis and Monte Carlo simulations we show that hydrogen is located in octahedral z sites and quantify its vibrational amplitude of 0.2 Å.
Collapse
Affiliation(s)
- Kristina Komander
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Tuan Tran
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Jitendra Saha
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Marcos V Moro
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Gunnar K Pálsson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Max Wolff
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| |
Collapse
|
20
|
Doppelbauer D, Aljabour A, Coskun H, Sun H, Gusenbauer M, Lumetzberger J, Primetzhofer D, Faina B, Duchoslav J, Kehrer M, Stifter D, Groiss H, Ney V, Ney A, Stadler P. P-type cobaltite oxide spinels enable efficient electrocatalytic oxygen evolution reaction. Mater Adv 2021; 2:5494-5500. [PMID: 34458848 PMCID: PMC8366392 DOI: 10.1039/d1ma00157d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Currently, energy-efficient electrocatalytic oxygen evolution from water involves the use of noble metal oxides. Here, we show that highly p-conducting zinc cobaltite spinel Zn1.2Co1.8O3.5 offers an enhanced electrocatalytic activity for oxygen evolution. We refer to previous studies on sputtered Zn-Co spinels with optimized conductivity for implementation as (p-type) transparent conducting oxides. Based on that, we manufacture off-stoichiometric conducting p-spinel catalytic anodes on tetragonal Ti, Au-Ti and hexagonal Al-doped ZnO carriers and report the evolution of O2 at Tafel slopes between 40.5 and 48 mV dec-1 and at overpotentials between 0.35 and 0.43 V (at 10 mA cm-2). The anodic stability, i.e., 50 h of continuous O2 electrolysis in 1 M KOH, suggests that increasing the conductivity is advantageous for electrolysis, particularly for reducing the ohmic losses and ensuring activity across the entire surface. We conclude by pointing out the merits of improving p-doping in Zn-Co spinels by optimized growth on a tetragonal Ti-carrier and their application as dimension-stable 3d-metal anodes.
Collapse
Affiliation(s)
- David Doppelbauer
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Abdalaziz Aljabour
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Halime Coskun
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - He Sun
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
- Linz Institute of Technology, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Markus Gusenbauer
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Julia Lumetzberger
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University Box 516 751 20 Uppsala Sweden
| | - Bogdan Faina
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Jiri Duchoslav
- Center for Surface and Nanoanalytics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Matthias Kehrer
- Center for Surface and Nanoanalytics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - David Stifter
- Center for Surface and Nanoanalytics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Heiko Groiss
- Center for Surface and Nanoanalytics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
- Christian Doppler Laboratory for Nanoscale Phase Transformations, Center for Surface and Nanoanalytics, Johannes Kepler University Linz Altenberger Str. 69 4040 Linz Austria
| | - Verena Ney
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Andreas Ney
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| | - Philipp Stadler
- Institute of Physical Chemistry, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
- Linz Institute of Technology, Johannes Kepler University Linz Altenbergerstrasse 69 4040 Linz Austria
| |
Collapse
|
21
|
Ström P, Primetzhofer D. In-situ measurement of diffusion and surface segregation of W and Ta in bare and W-coated EUROFER97 during thermal annealing. Nuclear Materials and Energy 2021. [DOI: 10.1016/j.nme.2021.100979] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
22
|
Affiliation(s)
| | - Marcos V. Moro
- Department of Physics and Astronomy Uppsala University Uppsala Sweden
| | - Valentina Paneta
- Department of Physics and Astronomy Uppsala University Uppsala Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy Uppsala University Uppsala Sweden
- Tandem Laboratory Uppsala University Uppsala Sweden
| |
Collapse
|
23
|
Mathayan V, Sortica M, Primetzhofer D. Determining the chronological sequence of inks deposited with different writing and printing tools using ion beam analysis. J Forensic Sci 2021; 66:1401-1409. [PMID: 33748972 DOI: 10.1111/1556-4029.14705] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/24/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
Determining the sequence of inks in a questioned document is important in forensic science. Conventional and micro beam-based ion beam analysis using Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission were employed to study the depth distribution of chemical elements in plain paper and inks/toner deposited by different pens as well as inkjet and laser printers. Composition depth profiling with high lateral resolution was performed with focus on areas where two different coloring agents overlapped. We identify under which conditions the sequence of inks deposited can be reconstructed, analyzing the continuity of characteristic contributions to the obtained signals, with a focus on the depth-resolved RBS data. The order of deposition was correctly determined for combinations of two different laser printers and in certain cases for pens. Results indicate a potential for analysis, depending on the composition of staining agent, that is, in particular if heavy species are present in sufficiently high concentration. In such cases, also characters obscured or modified by an agent of different composition can be revealed. Changing the probing depth by modifying the beam energy could yield additional information.
Collapse
Affiliation(s)
- Vairavel Mathayan
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | | | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.,Tandem Laboratory, Uppsala University, Uppsala, Sweden
| |
Collapse
|
24
|
Keuter P, Ravensburg AL, Hans M, Karimi Aghda S, Holzapfel DM, Primetzhofer D, Schneider JM. A Proposal for a Composite with Temperature-Independent Thermophysical Properties: HfV 2-HfV 2O 7. Materials (Basel) 2020; 13:E5021. [PMID: 33171727 PMCID: PMC7664386 DOI: 10.3390/ma13215021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 11/16/2022]
Abstract
The HfV2-HfV2O7 composite is proposed as a material with potentially temperature-independent thermophysical properties due to the combination of anomalously increasing thermoelastic constants of HfV2 with the negative thermal expansion of HfV2O7. Based on literature data, the coexistence of both a near-zero temperature coefficient of elasticity and a coefficient of thermal expansion is suggested for a composite with a phase fraction of approximately 30 vol.% HfV2 and 70 vol.% HfV2O7. To produce HfV2-HfV2O7 composites, two synthesis pathways were investigated: (1) annealing of sputtered HfV2 films in air to form HfV2O7 oxide on the surface and (2) sputtering of HfV2O7/HfV2 bilayers. The high oxygen mobility in HfV2 is suggested to inhibit the formation of crystalline HfV2-HfV2O7 composites by annealing HfV2 in air due to oxygen-incorporation-induced amorphization of HfV2. Reducing the formation temperature of crystalline HfV2O7 from 550 °C, as obtained upon annealing, to 300 °C using reactive sputtering enables the synthesis of crystalline bilayered HfV2-HfV2O7.
Collapse
Affiliation(s)
- Philipp Keuter
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
| | - Anna L. Ravensburg
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden;
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
| | - Soheil Karimi Aghda
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
| | - Damian M. Holzapfel
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden;
| | - Jochen M. Schneider
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany; (A.L.R.); (M.H.); (S.K.A.); (D.M.H.); (J.M.S.)
| |
Collapse
|
25
|
Holeňák R, Lohmann S, Primetzhofer D. Contrast modes in a 3D ion transmission approach at keV energies. Ultramicroscopy 2020; 217:113051. [PMID: 32615322 DOI: 10.1016/j.ultramic.2020.113051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 10/24/2022]
Abstract
We present options for visualizing contrast maps in 3D ion transmission experiments. Simultaneous measurement of angular distributions and flight time of ions transmitted through self-supporting, single-crystalline silicon foils allows for mapping of intensity and different energy loss moments. The transmitted projectiles were detected mainly for random beam-sample orientation using pulsed beams of He ions and protons with incident energies 50 and 200 keV. Differences in contrast, observed when varying the projectile type and energy, can be attributed to sample nuclear and electronic structure and bear witness to impact parameter dependent energy loss processes. Our results provide a base for interpretation of data obtained in prospective transmission studies when for example using a helium ion microscope.
Collapse
Affiliation(s)
- R Holeňák
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
| | - S Lohmann
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - D Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| |
Collapse
|
26
|
Tran TT, Jablonka L, Lavoie C, Zhang Z, Primetzhofer D. In-situ characterization of ultrathin nickel silicides using 3D medium-energy ion scattering. Sci Rep 2020; 10:10249. [PMID: 32581281 PMCID: PMC7314745 DOI: 10.1038/s41598-020-66464-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/20/2020] [Indexed: 12/03/2022] Open
Abstract
Epitaxial ultrathin films are of utmost importance for state-of-the-art nanoelectronic devices, such as MOSFET transistors and non-volatile memories. At the same time, as the film thickness is reduced to a few nanometers, characterization of the materials is becoming challenging for commonly used methods. In this report, we demonstrate an approach for in-situ characterization of phase transitions of ultrathin nickel silicides using 3D medium-energy ion scattering. The technique provides simultaneously depth-resolved composition and real-space crystallography of the silicide films using a single sample and with a non-invasive probe. We show, for 10 nm Ni films on Si, that their composition follows a normal transition sequence, such as Ni-Ni2Si-NiSi. However, the transition process is significantly different for samples with initial Ni thickness of 3 nm. Depth-resolved crystallography shows that the Ni films transform from an as-deposited disordered layer to an epitaxial silicide layer at the temperature of ~290 °C, significantly lower than previously reported. The high depth resolution of the technique permits us to determine the composition of the ultrathin films to be 38% Ni and 62% Si.
Collapse
Affiliation(s)
- Tuan Thien Tran
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden.
| | - Lukas Jablonka
- Solid State Electronics, The Ångström Laboratory, Uppsala University, SE-75121, Uppsala, Sweden
| | - Christian Lavoie
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York, 10598, USA
| | - Zhen Zhang
- Solid State Electronics, The Ångström Laboratory, Uppsala University, SE-75121, Uppsala, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| |
Collapse
|
27
|
Bruckner B, Hans M, Nyberg T, Greczynski G, Bauer P, Primetzhofer D. Electronic excitation of transition metal nitrides by light ions with keV energies. J Phys Condens Matter 2020; 32:405502. [PMID: 32330905 DOI: 10.1088/1361-648x/ab8cd9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigated the specific electronic energy deposition by protons and He ions with keV energies in different transition metal nitrides of technological interest. Data were obtained from two different time-of-flight ion scattering setups and show excellent agreement. For protons interacting with light nitrides, i.e. TiN, VN and CrN, very similar stopping cross sections per atom were found, which coincide with literature data of N2 gas for primary energies ⩽25 keV. In case of the chemically rather similar nitrides with metal constituents from the 5th and 6th period, i.e. ZrN and HfN, the electronic stopping cross sections were measured to exceed what has been observed for molecular N2 gas. For He ions, electronic energy loss in all nitrides was found to be significantly higher compared to the equivalent data of N2 gas. Additionally, deviations from velocity proportionality of the observed specific electronic energy loss are observed. A comparison with predictions from density functional theory for protons and He ions yields a high apparent efficiency of electronic excitations of the target for the latter projectile. These findings are considered to indicate the contributions of additional mechanisms besides electron hole pair excitations, such as electron capture and loss processes of the projectile or promotion of target electrons in atomic collisions.
Collapse
Affiliation(s)
- Barbara Bruckner
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden. Institute of Experimental Physics-AOP, Johannes-Kepler University Linz, 4040 Linz, Austria
| | | | | | | | | | | |
Collapse
|
28
|
Lohmann S, Primetzhofer D. Disparate Energy Scaling of Trajectory-Dependent Electronic Excitations for Slow Protons and He Ions. Phys Rev Lett 2020; 124:096601. [PMID: 32202865 DOI: 10.1103/physrevlett.124.096601] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
We have simultaneously measured angular distributions and electronic energy loss of helium ions and protons directly transmitted through self-supporting, single-crystalline silicon foils. We have compared the energy loss along channeled and random trajectories for incident ion energies between 50 and 200 keV. For all studied cases the energy loss in channeling geometry is found lower than in random geometry. In the case of protons, this difference increases with initial ion energy. This behavior can be explained by the increasing contribution of excitations of core electrons, which are more likely to happen at small impact parameters accessible only in random geometry. For helium ions we observe a reverse trend-a decrease of the difference between channeled and random energy loss for increasing ion energy. Because of the inefficiency of core-electron excitations even at small impact parameters at such low energies, another mechanism has to be the cause for the observed difference. We provide evidence that the observation originates from reionization events induced by close collisions of helium ions occurring only along random trajectories.
Collapse
Affiliation(s)
- S Lohmann
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - D Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| |
Collapse
|
29
|
Gründlinger P, Györök M, Wolfmayr S, Breuer T, Primetzhofer D, Bruckner B, Monkowius U, Wagner T. Aggregation of Au(i)-complexes on amorphous substrates governed by aurophilicity. Dalton Trans 2019; 48:14712-14723. [PMID: 31539005 DOI: 10.1039/c9dt03049b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In single crystals of 2-naphthylisonitrile-gold(i)-halide (halide = Cl, Br, I) complexes, AuAu distances are found to be significantly shorter than twice the van der Waals radius, indicating attractive interactions between gold atoms in adjacent molecules. In the particular case of the studied 2-naphthylisonitrile-gold(i) complexes, homodimers are the common structural motifs, in which the linearly coordinated gold exhibits a crossed swords arrangement with the Au atoms of two molecules being at the intersection point. The crossed swords motif is preserved upon physical vapour deposition of both the chlorine and bromine derivatives on amorphous substrates like glass and glassy carbon. The determined activation energies of desorption for the chlorine (0.9 eV) and the bromine (1.2 eV) derivative are comparable to that of unsubstituted naphthalene. Using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ion scattering (RBS), we confirmed the chemical integrity of the molecules in thin films and revealed the orientation of the crossed swords dimers with respect to the substrate surface.
Collapse
Affiliation(s)
- Petra Gründlinger
- Johannes Kepler University Linz, Institute of Experimental Physics, Surface Science Division, Altenberger Straße 69, 4040 Linz, Austria.
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Stelzer B, Chen X, Bliem P, Hans M, Völker B, Sahu R, Scheu C, Primetzhofer D, Schneider JM. Remote Tracking of Phase Changes in Cr 2AlC Thin Films by In-situ Resistivity Measurements. Sci Rep 2019; 9:8266. [PMID: 31164687 PMCID: PMC6547878 DOI: 10.1038/s41598-019-44692-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 11/09/2022] Open
Abstract
Resistivity changes of magnetron sputtered, amorphous Cr2AlC thin films were measured during heating in vacuum. Based on correlative X-ray diffraction, in-situ and ex-situ selected area electron diffraction measurements and differential scanning calorimetry data from literature it is evident that the resistivity changes at 552 ± 4 and 585 ± 13 °C indicate the phase transitions from amorphous to a hexagonal disordered solid solution structure and from the latter to MAX phase, respectively. We have shown that phase changes in Cr2AlC thin films can be revealed by in-situ measurements of thermally induced resistivity changes.
Collapse
Affiliation(s)
- Bastian Stelzer
- Materials Chemistry, RWTH Aachen University, D-52074, Aachen, Germany.
| | - Xiang Chen
- Materials Chemistry, RWTH Aachen University, D-52074, Aachen, Germany
| | - Pascal Bliem
- Materials Chemistry, RWTH Aachen University, D-52074, Aachen, Germany
| | - Marcus Hans
- Materials Chemistry, RWTH Aachen University, D-52074, Aachen, Germany
| | - Bernhard Völker
- Max-Planck-Institut für Eisenforschung GmbH, D-40237, Düsseldorf, Germany
| | - Rajib Sahu
- Max-Planck-Institut für Eisenforschung GmbH, D-40237, Düsseldorf, Germany
| | - Christina Scheu
- Max-Planck-Institut für Eisenforschung GmbH, D-40237, Düsseldorf, Germany
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, S-75120, Uppsala, Sweden
| | | |
Collapse
|
31
|
Arvizu MA, Qu HY, Cindemir U, Qiu Z, Rojas-González EA, Primetzhofer D, Granqvist CG, Österlund L, Niklasson GA. Electrochromic WO 3 thin films attain unprecedented durability by potentiostatic pretreatment. J Mater Chem A Mater 2019; 7:2908-2918. [PMID: 30931123 PMCID: PMC6394890 DOI: 10.1039/c8ta09621j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/09/2019] [Indexed: 06/09/2023]
Abstract
Electrochromic windows and glass facades are able to impart energy efficiency jointly with indoor comfort and convenience. Long-term durability is essential for practical implementation of this technology and has recently attracted broad interest. Here we show that a simple potentiostatic pretreatment of sputter-deposited thin films of amorphous WO3-the most widely studied electrochromic material-can yield unprecedented durability for charge exchange and optical modulation under harsh electrochemical cycling in a Li-ion-conducting electrolyte and effectively evades harmful trapping of Li. The pretreatment consisted of applying a voltage of 6.0 V vs. Li/Li+ for several hours to a film backed by a transparent conducting In2O3:Sn layer. Associated compositional and structural modifications were probed by several techniques, and improved durability was associated with elemental intermixing at the WO3/ITO and ITO/glass boundaries as well as with carbonaceous solid-electrolyte interfacial layers on the WO3 films. Our work provides important new insights into long-term durability of ion-exchange-based devices.
Collapse
Affiliation(s)
- Miguel A Arvizu
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Hui-Ying Qu
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage , School of Chemistry and Chemical Engineering , Harbin Institute of Technology , 150001 Harbin , China
| | - Umut Cindemir
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Zhen Qiu
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Edgar A Rojas-González
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Daniel Primetzhofer
- Department of Physics and Astronomy , The Ångström Laboratory , Uppsala University , P.O. Box 516 , SE-751 20 Uppsala , Sweden
| | - Claes G Granqvist
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Lars Österlund
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| | - Gunnar A Niklasson
- Department of Engineering Sciences , The Ångström Laboratory , Uppsala University , P.O. Box 534 , SE-751 21 Uppsala , Sweden .
| |
Collapse
|
32
|
Sortica MA, Paneta V, Bruckner B, Lohmann S, Nyberg T, Bauer P, Primetzhofer D. On the Z 1-dependence of electronic stopping in TiN. Sci Rep 2019; 9:176. [PMID: 30655585 PMCID: PMC6336800 DOI: 10.1038/s41598-018-36765-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 11/27/2018] [Indexed: 11/17/2022] Open
Abstract
We present a thorough experimental study of electronic stopping of H, He, B, N, Ne and Al ions in TiN with the aim to learn about the energy loss mechanisms of slow ions. The energy loss was measured by means of time-of-flight medium-energy ion scattering. Thin films of TiN on silicon with a δ-layer of W at the TiN/Si interface were used as targets. We compare our results to non-linear density functional theory calculations, examining electron-hole pair excitations by screened ions in a free electron gas in the static limit, with a density equivalent to the expected value for TiN. These calculations predict oscillations in the electronic stopping power for increasing atomic number Z1 of the projectile. An increasing discrepancy between our experimental results and predictions by theory for increasing Z1 was observed. This observation can be attributed to contributions from energy loss channels different from electron-hole pair excitation in binary Coulomb collisions.
Collapse
Affiliation(s)
- Mauricio A Sortica
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden.
| | - Valentina Paneta
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden
| | - Barbara Bruckner
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden
- Atomic Physics and Surface, Johannes Kepler University, A-4040, Linz, Austria
| | - Svenja Lohmann
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden
| | - Tomas Nyberg
- Department of Engineering Sciences, Uppsala University, Box 534, S-751 21, Uppsala, Sweden
| | - Peter Bauer
- Atomic Physics and Surface, Johannes Kepler University, A-4040, Linz, Austria
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden
| |
Collapse
|
33
|
Qu HY, Primetzhofer D, Qiu Z, Österlund L, Granqvist CG, Niklasson GA. Cation-/Anion-Based Electrochemical Degradation and Rejuvenation of Electrochromic Nickel Oxide Thin Films. ChemElectroChem 2018. [DOI: 10.1002/celc.201800791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hui-Ying Qu
- Department of Engineering Sciences The Ångström Laboratory; Uppsala University; SE-75121 Uppsala Sweden
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical Engineering; Harbin Institute of Technology; 150001 Harbin China
| | - Daniel Primetzhofer
- Department of Physics and Astronomy The Ångström Laboratory; Uppsala University; SE-75120 Uppsala Sweden
| | - Zhen Qiu
- Department of Engineering Sciences The Ångström Laboratory; Uppsala University; SE-75121 Uppsala Sweden
| | - Lars Österlund
- Department of Engineering Sciences The Ångström Laboratory; Uppsala University; SE-75121 Uppsala Sweden
| | - Claes G. Granqvist
- Department of Engineering Sciences The Ångström Laboratory; Uppsala University; SE-75121 Uppsala Sweden
| | - Gunnar A. Niklasson
- Department of Engineering Sciences The Ångström Laboratory; Uppsala University; SE-75121 Uppsala Sweden
| |
Collapse
|
34
|
Qu HY, Primetzhofer D, Arvizu MA, Qiu Z, Cindemir U, Granqvist CG, Niklasson GA. Electrochemical Rejuvenation of Anodically Coloring Electrochromic Nickel Oxide Thin Films. ACS Appl Mater Interfaces 2017; 9:42420-42424. [PMID: 29164852 DOI: 10.1021/acsami.7b13815] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nickel oxide thin films are of major importance as anodically coloring components in electrochromic smart windows with applications in energy-efficient buildings. However, the optical performance of these films degrades upon extended electrochemical cycling, which has hampered their implementation. Here, we use a potentiostatic treatment to rejuvenate degraded nickel oxide thin films immersed in electrolytes of LiClO4 in propylene carbonate. Time-of-flight elastic recoil detection analysis provided unambiguous evidence that both Li+ ions and chlorine-based ions participate in the rejuvenation process. Our work provides new perspectives for developing ion-exchange-based devices embodying nickel oxide.
Collapse
Affiliation(s)
- Hui-Ying Qu
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology , 150001 Harbin, China
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, The Ångström Laboratory, Uppsala University , SE-75120 Uppsala, Sweden
| | - Miguel A Arvizu
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
| | - Zhen Qiu
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
| | - Umut Cindemir
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
| | - Claes G Granqvist
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
| | - Gunnar A Niklasson
- Department of Engineering Sciences, The Ångström Laboratory, Uppsala University , SE-75121 Uppsala, Sweden
| |
Collapse
|
35
|
Roth D, Bruckner B, Undeutsch G, Paneta V, Mardare AI, McGahan CL, Dosmailov M, Juaristi JI, Alducin M, Pedarnig JD, Haglund RF, Primetzhofer D, Bauer P. Electronic Stopping of Slow Protons in Oxides: Scaling Properties. Phys Rev Lett 2017; 119:163401. [PMID: 29099197 DOI: 10.1103/physrevlett.119.163401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 06/07/2023]
Abstract
Electronic stopping of slow protons in ZnO, VO_{2} (metal and semiconductor phases), HfO_{2}, and Ta_{2}O_{5} was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al_{2}O_{3} and SiO_{2} reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies. Instead, the oxygen 2p states are decisive, as corroborated by density functional theory calculations of the electronic densities of states. Hence, at low ion velocities the SCS of an oxide primarily scales with its oxygen density.
Collapse
Affiliation(s)
- D Roth
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - B Bruckner
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - G Undeutsch
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - V Paneta
- Institutionen för Fysik och Astronomi, Uppsala Universitet, Box 516, S-751 20 Uppsala, Sweden
| | - A I Mardare
- Institut für Chemische Technologie Anorganischer Stoffe, Johannes-Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz, Austria
| | - C L McGahan
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - M Dosmailov
- Institut für Angewandte Physik, Johannes-Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz, Austria
| | - J I Juaristi
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20018 Donostia-San Sebastián, Spain
| | - M Alducin
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
| | - J D Pedarnig
- Institut für Angewandte Physik, Johannes-Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz, Austria
| | - R F Haglund
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - D Primetzhofer
- Institutionen för Fysik och Astronomi, Uppsala Universitet, Box 516, S-751 20 Uppsala, Sweden
| | - P Bauer
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| |
Collapse
|
36
|
Chulapakorn T, Sychugov I, Saveda Suvanam S, Linnros J, Primetzhofer D, Hallén A. Influence of swift heavy ion irradiation on the photoluminescence of Si-nanoparticles and defects in SiO 2. Nanotechnology 2017; 28:375603. [PMID: 28745617 DOI: 10.1088/1361-6528/aa824f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The influence of swift heavy ion (SHI) irradiation on the photoluminescence (PL) of silicon nanoparticles (SiNPs) and defects in SiO2-film is investigated. SiNPs were formed by implantation of 70 keV Si+ and subsequent thermal annealing to produce optically active SiNPs and to remove implantation-induced defects. Seven different ion species with energy between 3-36 MeV and fluence from 1011-1014 cm-2 were employed for irradiation of the implanted samples prior to the thermal annealing. Induced changes in defect and SiNP PL were characterized and correlated with the specific energy loss of the employed SHIs. We find that SHI irradiation, performed before the thermal annealing process, affects both defect and SiNP PL. The change of defect and SiNP PL due to SHI irradiation is found to show a threshold-like behaviour with respect to the electronic stopping power, where a decrease in defect PL and an anticorrelated increase in SiNP PL after the subsequent thermal annealing are observed for electronic stopping exceeding 3-5 keV nm-1. PL intensities are also compared as a function of total energy deposition and nuclear energy loss. The observed effects can be explained by ion track formation as well as a different type of annealing mechanisms active for SHI irradiation compared to the thermal annealing.
Collapse
Affiliation(s)
- Thawatchart Chulapakorn
- Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-751 20 Uppsala, Sweden
| | | | | | | | | | | |
Collapse
|
37
|
Fluch U, Paneta V, Primetzhofer D, Ott S. Uniform distribution of post-synthetic linker exchange in metal-organic frameworks revealed by Rutherford backscattering spectrometry. Chem Commun (Camb) 2017; 53:6516-6519. [PMID: 28573305 PMCID: PMC5846729 DOI: 10.1039/c7cc02631e] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Rutherford backscattering spectrometry (RBS) has been used for the first time to study post-synthetic linker exchange (PSE) in metal-organic frameworks. RBS is a non-invasive method to quantify the amount of introduced linker, as well as providing a means for depth profiling in order to identify the preferred localization of the introduced linker. The exchange of benzenedicarboxylate (bdc) by similarly sized 2-iodobenzenedicarboxylate (I-bdc) proceeds considerably slower than migration of I-dbc through the UiO-66 crystal. Consequently, the I-bdc is found evenly distributed throughout the UiO-66 samples, even at very short PSE exposure times.
Collapse
Affiliation(s)
- Ulrike Fluch
- Department of Chemistry – Ångstro¨m Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Valentina Paneta
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Daniel Primetzhofer
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Sascha Ott
- Department of Chemistry – Ångstro¨m Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| |
Collapse
|
38
|
Roth D, Bruckner B, Moro MV, Gruber S, Goebl D, Juaristi JI, Alducin M, Steinberger R, Duchoslav J, Primetzhofer D, Bauer P. Electronic Stopping of Slow Protons in Transition and Rare Earth Metals: Breakdown of the Free Electron Gas Concept. Phys Rev Lett 2017; 118:103401. [PMID: 28339263 DOI: 10.1103/physrevlett.118.103401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Indexed: 06/06/2023]
Abstract
The electronic stopping cross sections (SCS) of Ta and Gd for slow protons have been investigated experimentally. The data are compared to the results for Pt and Au to learn how electronic stopping in transition and rare earth metals correlates with features of the electronic band structures. The extraordinarily high SCS observed for protons in Ta and Gd cannot be understood in terms of a free electron gas model, but are related to the high densities of both occupied and unoccupied electronic states in these metals.
Collapse
Affiliation(s)
- D Roth
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - B Bruckner
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - M V Moro
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, Brasil
| | - S Gruber
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - D Goebl
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
| | - J I Juaristi
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20018 San Sebastián, Spain
| | - M Alducin
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
| | - R Steinberger
- Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Zentrum für Oberflächen- und Nanoanalytik (ZONA), Johannes-Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz Austria
| | - J Duchoslav
- Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Zentrum für Oberflächen- und Nanoanalytik (ZONA), Johannes-Kepler Universität Linz, Altenbergerstraße 69, A-4040 Linz Austria
| | - D Primetzhofer
- Institutionen för Fysik och Astronomi, Uppsala Universitet, Box 516, S-751 20 Uppsala, Sweden
| | - P Bauer
- Johannes-Kepler Universität Linz, IEP-AOP, Altenbergerstraße 69, A-4040 Linz, Austria
- Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián, Spain
| |
Collapse
|
39
|
Hunold O, Keuter P, Bliem P, Music D, Wittmers F, Ravensburg AL, Primetzhofer D, Schneider JM. Elastic properties of amorphous T 0.75Y 0.75B 14 (T = Sc, Ti, V, Y, Zr, Nb) and the effect of O incorporation on bonding, density and elasticity (T' = Ti, Zr). J Phys Condens Matter 2017; 29:085404. [PMID: 28081008 DOI: 10.1088/1361-648x/aa5375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have systematically studied the effect of transition metal valence electron concentration (VEC) of amorphous T 0.75Y0.75B14 (a-T 0.75Y0.75B14, T = Sc, Ti, V, Y, Zr, Nb) on the elastic properties, bonding, density and electronic structure using ab initio molecular dynamics. As the transition metal VEC is increased in both periods, the bulk modulus increases linearly with molar- and mass density. This trend can be understood by a concomitant decrease in cohesive energy. T' = Ti and Zr were selected to validate the predicted data experimentally. A-Ti0.74Y0.80B14 and a-Zr0.75Y0.75B14 thin films were synthesized by high power pulsed magnetron sputtering. Chemical composition analysis revealed the presence of up to 5 at.% impurities, with O being the largest fraction. The measured Young's modulus values for a-Ti0.74Y0.80B14 (301 ± 8 GPa) and a-Zr0.75Y0.75B14 (306 ± 9 GPa) are more than 20% smaller than the predicted ones. The influence of O incorporation on the elastic properties for these selected systems was theoretically studied, exemplarily in a-Ti0.75Y0.75B12.75O1.25. Based on ab initio data, we suggest that a-Ti0.75Y0.75B14 exhibits a very dense B network, which is partly severed in a-Ti0.75Y0.75B12.75O1.25. Upon O incorporation, the average coordination number of B and the molar density decrease by 9% and 8%, respectively. Based on these data the more than 20% reduced Young's modulus obtained experimentally for films containing impurities compared to the calculated Young's modulus for a-Ti0.75Y0.75B14 (without incorporated oxygen) can be rationalized. The presence of oxygen impurities disrupts the strong B network causing a concomitant decrease in molar density and Young's modulus. Very good agreement between the measured and calculated Young's modulus values is obtained if the presence of impurities is considered in the calculations. The implications of these findings are that prediction efforts regarding the elastic properties of amorphous borides containing oxygen impurities on the at.% level are flawed without taking the presence of impurities into account.
Collapse
Affiliation(s)
- Oliver Hunold
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Kiefer D, Yu L, Fransson E, Gómez A, Primetzhofer D, Amassian A, Campoy‐Quiles M, Müller C. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics. Adv Sci (Weinh) 2017; 4:1600203. [PMID: 28105396 PMCID: PMC5238747 DOI: 10.1002/advs.201600203] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Indexed: 05/02/2023]
Abstract
Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm-1 and Seebeck coefficient from 100 to 60 μV K-1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m-1 K-1 gives rise to a thermoelectric Figure of merit ZT ∼ 10-4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.
Collapse
Affiliation(s)
- David Kiefer
- Department of Chemistry and Chemical EngineeringChalmers University of Technology41296GöteborgSweden
| | - Liyang Yu
- Department of Chemistry and Chemical EngineeringChalmers University of Technology41296GöteborgSweden
- Physical Sciences & Engineering Division, and KAUST Solar Center (KSC)King Abdullah University of Science and Technology (KAUST)Thuwal23955‐6900Saudi Arabia
| | - Erik Fransson
- Department of PhysicsChalmers University of Technology41296GöteborgSweden
| | - Andrés Gómez
- Institut de Ciència de Materials de Barcelona (ICMAB‐CSIC)Esfera de la UAB08193BellaterraSpain
| | | | - Aram Amassian
- Physical Sciences & Engineering Division, and KAUST Solar Center (KSC)King Abdullah University of Science and Technology (KAUST)Thuwal23955‐6900Saudi Arabia
| | - Mariano Campoy‐Quiles
- Institut de Ciència de Materials de Barcelona (ICMAB‐CSIC)Esfera de la UAB08193BellaterraSpain
| | - Christian Müller
- Department of Chemistry and Chemical EngineeringChalmers University of Technology41296GöteborgSweden
| |
Collapse
|
41
|
Kriegner D, Furthmüller J, Kirchschlager R, Endres J, Horak L, Cejpek P, Reichlova H, Marti X, Primetzhofer D, Ney A, Bauer G, Bechstedt F, Holy V, Springholz G. Ferroelectric phase transition in multiferroic Ge 1-x Mn x Te driven by local lattice distortions. Phys Rev B 2016; 94:054112. [PMID: 28459114 PMCID: PMC5404721 DOI: 10.1103/physrevb.94.054112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The evolution of local ferroelectric lattice distortions in multiferroic Ge1-x Mn x Te is studied by x-ray diffraction, x-ray absorption spectroscopy and density functional theory. We show that the anion/cation displacements smoothly decrease with increasing Mn content, thereby reducing the ferroelectric transition from 700 to 100 K at x = 0.5, where the ferromagnetic Curie temperature reaches its maximum. First principles calculations explain this quenching by different local bond contributions of the Mn 3d shell compared to the Ge 4s shell in excellent quantitative agreement with the experiments.
Collapse
Affiliation(s)
- Dominik Kriegner
- Department of Condensed Matter Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic
| | - Jürgen Furthmüller
- Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Raimund Kirchschlager
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Jan Endres
- Department of Condensed Matter Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic
| | - Lukas Horak
- Department of Condensed Matter Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic
| | - Petr Cejpek
- Department of Condensed Matter Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic
| | - Helena Reichlova
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - Xavier Marti
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - Daniel Primetzhofer
- Ion Physics Department, The Ångström Laboratory, Uppsala University, P.O. Box 534, SE-75121, Sweden
| | - Andreas Ney
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Günther Bauer
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Friedhelm Bechstedt
- Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Vaclav Holy
- Department of Condensed Matter Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic
| | - Gunther Springholz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria
| |
Collapse
|
42
|
Arvizu MA, Wen RT, Primetzhofer D, Klemberg-Sapieha JE, Martinu L, Niklasson GA, Granqvist CG. Galvanostatic Ion Detrapping Rejuvenates Oxide Thin Films. ACS Appl Mater Interfaces 2015; 7:26387-26390. [PMID: 26599729 DOI: 10.1021/acsami.5b09430] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ion trapping under charge insertion-extraction is well-known to degrade the electrochemical performance of oxides. Galvanostatic treatment was recently shown capable to rejuvenate the oxide, but the detailed mechanism remained uncertain. Here we report on amorphous electrochromic (EC) WO3 thin films prepared by sputtering and electrochemically cycled in a lithium-containing electrolyte under conditions leading to severe loss of charge exchange capacity and optical modulation span. Time-of-flight elastic recoil detection analysis (ToF-ERDA) documented pronounced Li(+) trapping associated with the degradation of the EC properties and, importantly, that Li(+) detrapping, caused by a weak constant current drawn through the film for some time, could recover the original EC performance. Thus, ToF-ERDA provided direct and unambiguous evidence for Li(+) detrapping.
Collapse
Affiliation(s)
| | | | | | | | - Ludvik Martinu
- Department of Engineering Physics, École Polytechnique de Montréal , Montreal, Quebec H3C 3A7, Canada
| | | | | |
Collapse
|
43
|
Abstract
Using density functional theory, we have systematically explored the 1a and 1b vacancy filling in NbO (space group Pm-3m) with Nb and N, respectively, to design compounds with large Seebeck coefficients. The most dominating effect was identified for filling of 1b Wyckoff sites with N giving rise to a fivefold increase in the Seebeck coefficient. This may be understood based on the electronic structure. Nb d-nonmetal p hybridization induces quantum confinement and hence enables the enhancement of the Seebeck coefficient. This was validated by measuring the Seebeck coefficient of reactively sputtered thin films. At 800 °C these electrically conductive oxynitrides exhibit the Seebeck coefficient of -70 µV K(-1), which is the largest absolute value ever reported for these compounds.
Collapse
Affiliation(s)
- Denis Music
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen, Germany
| | | | | | | | | |
Collapse
|
44
|
Lechner RT, Fritz-Popovski G, Yarema M, Heiss W, Hoell A, Schülli T, Primetzhofer D, Eibelhuber M, Paris O. Crystal Phase Transitions in the Shell of PbS/CdS Core/Shell Nanocrystals Influences Photoluminescence Intensity. Chem Mater 2014; 26:5914-5922. [PMID: 25673918 PMCID: PMC4311954 DOI: 10.1021/cm502521q] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/24/2014] [Indexed: 05/03/2023]
Abstract
We reveal the existence of two different crystalline phases, i.e., the metastable rock salt and the equilibrium zinc blende phase within the CdS-shell of PbS/CdS core/shell nanocrystals formed by cationic exchange. The chemical composition profile of the core/shell nanocrystals with different dimensions is determined by means of anomalous small-angle X-ray scattering with subnanometer resolution and is compared to X-ray diffraction analysis. We demonstrate that the photoluminescence emission of PbS nanocrystals can be drastically enhanced by the formation of a CdS shell. Especially, the ratio of the two crystalline phases in the shell significantly influences the photoluminescence enhancement. The highest emission was achieved for chemically pure CdS shells below 1 nm thickness with a dominant metastable rock salt phase fraction matching the crystal structure of the PbS core. The metastable phase fraction decreases with increasing shell thickness and increasing exchange times. The photoluminescence intensity depicts a constant decrease with decreasing metastable rock salt phase fraction but shows an abrupt drop for shells above 1.3 nm thickness. We relate this effect to two different transition mechanisms for changing from the metastable rock salt phase to the equilibrium zinc blende phase depending on the shell thickness.
Collapse
Affiliation(s)
- Rainer T. Lechner
- Institute
of Physics, Montanuniversitaet Leoben, 8700 Leoben, Austria
| | | | - Maksym Yarema
- Institute of Semiconductor and Solid
State Physics and Institute of Experimental Physics, Johannes
Kepler University Linz, 4040 Linz, Austria
| | - Wolfgang Heiss
- Institute of Semiconductor and Solid
State Physics and Institute of Experimental Physics, Johannes
Kepler University Linz, 4040 Linz, Austria
| | - Armin Hoell
- Helmholtz
Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | - Tobias
U. Schülli
- European
Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France
| | - Daniel Primetzhofer
- Institute of Semiconductor and Solid
State Physics and Institute of Experimental Physics, Johannes
Kepler University Linz, 4040 Linz, Austria
| | - Martin Eibelhuber
- Institute of Semiconductor and Solid
State Physics and Institute of Experimental Physics, Johannes
Kepler University Linz, 4040 Linz, Austria
| | - Oskar Paris
- Institute
of Physics, Montanuniversitaet Leoben, 8700 Leoben, Austria
| |
Collapse
|
45
|
Balitskii OA, Sytnyk M, Stangl J, Primetzhofer D, Groiss H, Heiss W. Tuning the localized surface plasmon resonance in Cu(2-x)Se nanocrystals by postsynthetic ligand exchange. ACS Appl Mater Interfaces 2014; 6:17770-5. [PMID: 25233007 PMCID: PMC4207552 DOI: 10.1021/am504296y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Nanoparticles exhibiting localized surface plasmon resonances (LSPR) are valuable tools traditionally used in a wide field of applications including sensing, imaging, biodiagnostics and medical therapy. Plasmonics in semiconductor nanocrystals is of special interest because of the tunability of the carrier densities in semiconductors, and the possibility to couple the plasmonic resonances to quantum confined excitonic transitions. Here, colloidal Cu2-xSe nanocrystals were synthesized, whose composition was shown by Rutherford backscattering analysis and electron dispersive X-ray spectroscopy, to exhibit Cu deficiency. The latter results in p-type doping causing LSPRs, in the present case around a wavelength of 1100 nm, closely matching the indirect band gap of Cu2-xSe. By partial exchange of the organic ligands to specific electron trapping or donating species the LSPR is fine-tuned to exhibit blue or red shifts, in total up to 200 nm. This tuning not only provides a convenient tool for post synthetic adjustments of LSPRs to specific target wavelength but the sensitive dependence of the resonance wavelength on surface charges makes these nanocrystals also interesting for sensing applications, to detect analytes dressed by functional groups.
Collapse
Affiliation(s)
- Olexiy A. Balitskii
- Institute of Semiconductor
and Solid State Physics, University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
- Department
of Electronics, Lviv Ivan Franko National
University, Dragomanov
Straße 50, 79005 Lviv, Ukraine
- Olexiy
A. Balitskii. E-mail:
| | - Mykhailo Sytnyk
- Institute of Semiconductor
and Solid State Physics, University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Julian Stangl
- Institute of Semiconductor
and Solid State Physics, University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Daniel Primetzhofer
- Ion Physics, Department of
Physics and Astronomy, Uppsala
University, 75120 Uppsala, Sweden
| | - Heiko Groiss
- Laboratory for
Electron Microscopy, Karlsruhe Institute of Technology
(KIT), 76128 Karlsruhe, Germany
| | - Wolfgang Heiss
- Institute of Semiconductor
and Solid State Physics, University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
- Materials
for Electronics and Energy Technology (i-MEET), Friedrich-Alexander-Universität, Erlangen-Nürnberg, Martensstraße 7, 91058 Erlangen, Germany
- Energie
Campus Nürnberg (EnCN), Fürther Straße 250, 90429 Nürnberg, Germany
| |
Collapse
|
46
|
Goebl D, Roth D, Primetzhofer D, Monreal RC, Abad E, Putz A, Bauer P. Quasi-resonant neutralization of He+ ions at a germanium surface. J Phys Condens Matter 2013; 25:485006. [PMID: 24201310 DOI: 10.1088/0953-8984/25/48/485006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
When low-energy He ions are scattered from a Ge surface, the fraction of positive ions exhibits characteristic oscillations as a function of ion energy. These oscillations are caused by quasi-resonant neutralization (qRN), a process which is active for materials with a narrow band nearly resonant with the unperturbed He 1s-level. In this paper we measure the fraction of He+ backscattered from Ge(100). In conjunction with recently developed theoretical methods, we extract quantitative information on the efficiency of qRN. Our evaluation reveals that qRN is a highly efficient process leading to ion fractions two orders of magnitude lower than in systems for which neutralization is only due to Auger processes.
Collapse
|
47
|
Monreal R, Goebl D, Primetzhofer D, Bauer P. Effects of the atomic level shift in the Auger neutralization rates of noble metal surfaces. Nucl Instrum Methods Phys Res B 2013; 315:206-212. [PMID: 25843996 PMCID: PMC4376069 DOI: 10.1016/j.nimb.2013.03.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 03/04/2013] [Indexed: 06/04/2023]
Abstract
In this work we compare characteristics of Auger neutralization of [Formula: see text] ions at noble metal and free-electron metal surfaces. For noble metals, we find that the position of the energy level of He with respect to the Fermi level has a non-negligible influence on the values of the calculated Auger rates through the evaluation of the surface dielectric susceptibility. We conclude that even though our calculated rates are accurate, further theoretical effort is needed to obtain realistic values of the energy level of He in front of these surfaces.
Collapse
Affiliation(s)
- R.C. Monreal
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Centre (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - D. Goebl
- Institut für Experimentalphysik, Abteilung für Atom-und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz, Austria
| | - D. Primetzhofer
- Institut für Experimentalphysik, Abteilung für Atom-und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz, Austria
| | - P. Bauer
- Institut für Experimentalphysik, Abteilung für Atom-und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz, Austria
| |
Collapse
|
48
|
Sytnyk M, Kirchschlager R, Bodnarchuk MI, Primetzhofer D, Kriegner D, Enser H, Stangl J, Bauer P, Voith M, Hassel AW, Krumeich F, Ludwig F, Meingast A, Kothleitner G, Kovalenko MV, Heiss W. Tuning the magnetic properties of metal oxide nanocrystal heterostructures by cation exchange. Nano Lett 2013; 13:586-93. [PMID: 23362940 PMCID: PMC3573734 DOI: 10.1021/nl304115r] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/26/2013] [Indexed: 05/15/2023]
Abstract
For three types of colloidal magnetic nanocrystals, we demonstrate that postsynthetic cation exchange enables tuning of the nanocrystal's magnetic properties and achieving characteristics not obtainable by conventional synthetic routes. While the cation exchange procedure, performed in solution phase approach, was restricted so far to chalcogenide based semiconductor nanocrystals, here ferrite-based nanocrystals were subjected to a Fe(2+) to Co(2+) cation exchange procedure. This allows tracing of the compositional modifications by systematic and detailed magnetic characterization. In homogeneous magnetite nanocrystals and in gold/magnetite core shell nanocrystals the cation exchange increases the coercivity field, the remanence magnetization, as well as the superparamagnetic blocking temperature. For core/shell nanoheterostructures a selective doping of either the shell or predominantly of the core with Co(2+) is demonstrated. By applying the cation exchange to FeO/CoFe(2)O(4) core/shell nanocrystals the Neél temperature of the core material is increased and exchange-bias effects are enhanced so that vertical shifts of the hysteresis loops are obtained which are superior to those in any other system.
Collapse
Affiliation(s)
- Mykhailo Sytnyk
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| | - Raimund Kirchschlager
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| | - Maryna I. Bodnarchuk
- Institute of Inorganic Chemistry,
Department of Chemistry and Applied Biosciences, ETH
Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and
Photovoltaics, EMPA-Swiss Federal Laboratories for Materials
Science and Technology, CH-8060, Switzerland
| | - Daniel Primetzhofer
- Ion physics, Department of Physics
and Astronomy, Uppsala University, 75120
Uppsala, Sweden
| | - Dominik Kriegner
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| | - Herbert Enser
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| | - Julian Stangl
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| | - Peter Bauer
- Institute
of Experimental Physics, University Linz, 4040 Linz, Austria
| | - Michael Voith
- Institute
for Chemical Technology
of Inorganic Materials, University Linz, 4040 Linz, Austria
| | - Achim Walter Hassel
- Institute
for Chemical Technology
of Inorganic Materials, University Linz, 4040 Linz, Austria
| | - Frank Krumeich
- Institute of Inorganic Chemistry,
Department of Chemistry and Applied Biosciences, ETH
Zurich, CH-8093, Switzerland
| | - Frank Ludwig
- Institut
für Elektrische Messtechnik
und Grundlagen der Elektrotechnik, TU Braunschweig, 38106 Braunschweig, Germany
| | - Arno Meingast
- Austrian Centre for Electron
Microscopy and Nanoanalysis, Institute for Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Gerald Kothleitner
- Austrian Centre for Electron
Microscopy and Nanoanalysis, Institute for Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Maksym V. Kovalenko
- Institute of Inorganic Chemistry,
Department of Chemistry and Applied Biosciences, ETH
Zurich, CH-8093, Switzerland
- Laboratory for Thin Films and
Photovoltaics, EMPA-Swiss Federal Laboratories for Materials
Science and Technology, CH-8060, Switzerland
| | - Wolfgang Heiss
- Institute of Semiconductor and
Solid State Physics, University Linz, Altenbergerstraße
69, 4040 Linz, Austria
| |
Collapse
|
49
|
Linnarsson MK, Hallén A, Åström J, Primetzhofer D, Legendre S, Possnert G. New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector. Rev Sci Instrum 2012; 83:095107. [PMID: 23020419 DOI: 10.1063/1.4750195] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the Ångström laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, (1)H(+), (4)He(+), and (11)B(+). Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted.
Collapse
Affiliation(s)
- M K Linnarsson
- KTH Royal Institute of Technology, School of Information and Communication Technology, Integrated Circuits and Devices, P.O. Box E229, SE-16440 Kista-Stockhom, Sweden.
| | | | | | | | | | | |
Collapse
|
50
|
Primetzhofer D, Spitz M, Taglauer E, Bauer P. Resonant charge transfer in low-energy ion scattering: Information depth in the reionization regime. Surf Sci 2011; 605:1913-1917. [PMID: 22053118 PMCID: PMC3165101 DOI: 10.1016/j.susc.2011.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 07/11/2011] [Indexed: 05/31/2023]
Abstract
Time-Of-Flight Low-energy ion scattering (TOF-LEIS) experiments were performed for He(+) ions scattered from Cu(100) and Cu(0.5)Au(0.5)(100). Probabilities for resonant neutralization and reionization in close collisions were deduced in a wide energy range. To learn about the information depth in LEIS, in a next step ion spectra were analyzed for polycrystalline Cu samples. The relative yield of backscattered projectiles, which have undergone distinct charge exchange processes, was calculated. Results indicate a strong contribution to the ion yield that origins from particles reionized in a close collision in deeper layers when experiments are performed at energies where reionization is prominent. The surface sensitivity of the ion signal at different energies is quantified. Based on these results, the total ion spectrum was quantitatively modelled by two consistent, but different approaches.
Collapse
Affiliation(s)
- D Primetzhofer
- Institut für Experimentalphysik, Johannes Kepler Universität Linz, A-4040 Linz, Austria
| | | | | | | |
Collapse
|