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Université de Fribourg

Metallic contact between MoS2 and Ni via Au nanoglue

Shi, Xinying ; Posysaev, Sergei ; Huttula, Marko ; Pankratov, Vladimir ; Hoszowska, Joanna ; Dousse, Jean?Claude ; Zeeshan, Faisal ; Niu, Yuran ; Zakharov, Alexei ; Li, Taohai ; Miroshnichenko, Olga ; Zhang, Meng ; Wang, Xiao ; Huang, Zhongjia ; Saukko, Sami ; González, Diego López ; Dijken, Sebastiaan van ; Alatalo, Matti ; Cao, Wei

In: Small, 2018, vol. 14, no. 22, p. 1704526

A critical factor for electronics based on inorganic layered crystals stems from the electrical contact mode between the semiconducting crystals and the metal counterparts in the electric circuit. Here, a materials tailoring strategy via nanocomposite decoration is carried out to reach metallic contact between MoS2 matrix and transition metal nanoparticles. Nickel nanoparticles (NiNPs) are ...

Université de Fribourg

Hypersatellite x-ray decay of $3d$ hollow-$K$-shell atoms produced by heavy-ion impact

Maillard, Yves-Patrick ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Berset, Michel ; Mauron, Olivier ; Raboud, Pierre-Alexandre ; Kavčič, Matjaz ; Rzadkiewicz, J. ; Banaś, Dariusz ; Tökési, K.

In: Physical Review A, 2018, vol. 98, no. 1, p. 012705

We report on the radiative decay of double K-shell vacancy states produced in solid Ca, V, Fe, and Cu targets by impact with about 10 MeV/amu C and Ne ions. The resulting K hypersatellite x-ray emission spectra were measured by means of high- energy-resolution spectroscopy using a von Hamos bent crystal spectrometer. The experiment was carried out at the Philips variable energy cyclotron of...

Université de Fribourg

High energy resolution off-resonant spectroscopy: A review

B³achucki, Wojciech ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Kayser, Yves ; Stachura, Regina ; Tyra³a, Krzysztof ; Wojtaszek, Klaudia ; Sá, Jacinto ; Szlachetko, Jakub

In: Spectrochimica Acta Part B: Atomic Spectroscopy, 2017, vol. 136, p. 23–33

We review the high energy resolution off-resonant spectroscopy (HEROS) technique. HEROS probes the unoccupied electronic states of matter in a single-shot manner thanks to the combination of off-resonant excitation around atomic core states using wavelength dispersive X-ray detection setups. In this review we provide a general introduction to the field of X-ray spectroscopy together with the...

Université de Fribourg

In situ high energy resolution off-resonant spectroscopy applied to a time-resolved study of single site Ta catalyst during oxidation

B³achucki, Wojciech ; Szlachetko, Jakub ; Kayser, Yves ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Zeeshan, Faisal ; Sá, Jacinto

In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017, vol. 411, no. Supplement C, p. 63–67

In the present work high energy resolution off-resonant X-ray spectroscopy (HEROS) was employed at a synchrotron to study a silica supported Ta(V) bisalkyl catalyst activated in hydrogen. The Ta Lα1 HEROS spectra were measured during oxidation of the starting complex and the relative species’ concentration was successfully retrieved as a function of time using the fingerprint HEROS spectra...

Université de Fribourg

Experimental determination of X-ray atomic fundamental parameters of nickel

Ménesguen, Yves ; Lepy, Marie-Christine ; Hönicke, Philipp ; Müller, Matthias ; Unterumsberger, Rainer ; Beckhoff, Burkhard ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Blachucki, W ; Ito, Y ; Yamashita, M ; Fukushima, S

In: Metrologia, 2017, p. -

Abstract X-ray atomic properties of Nickel were investigated in a singular approach that combines different experimental techniques to obtain new and useful reliable values of atomic fundamental parameters for X-ray spectrometric purposes and for comparison to theoretical predictions. We determined the mass attenuation coefficients in an energy range covering the L- and K- absorption edges,...

Université de Fribourg

Distribution of aluminum over different T-sites in ferrierite zeolites studied with aluminum valence to core X-ray emission spectroscopy

Bohinc, R. ; Hoszowska, Joanna ; Dousse, Jean-Claude ; B³achucki, Wojciech Maria ; Zeeshan, Faisal ; Kayser, Yves ; Nachtegaal, Maarten ; Pinar, A. B. ; Bokhoven, Jeroen A. van

In: Physical Chemistry Chemical Physics, 2017, vol. 19, no. 43, p. 29271–29277

The potential of valence to core Al X-ray emission spectroscopy to determine aluminum distribution in ferrierite zeolites was investigated. The recorded emission spectra of four samples prepared with different structure directing agents exhibit slight variations in the position of the main emission peak and the intensity of its low energy shoulder. Theoretical calculations indicate that an...

Université de Fribourg

Double K-shell photoionization and hypersatellite x-ray transitions of 12⩽Z⩽23 atoms

Hoszowska, Joanna ; Dousse, Jean-Claude ; Cao, Wei ; Fennane, Karima ; Kayser, Yves ; Szlachetko, Monika ; Szlachetko, Jakub ; Kavčič, Matjaz

In: Physical Review A, 2010, vol. 82, no. 6, p. 063408

Single-photon double K-shell ionization of low-Z neutral atoms in the range 12⩽Z⩽23 is investigated. The experimental method was based on measurements of the high- resolution Kαh hypersatellite x-ray spectra following the radiative decay of the K-shell double-vacancy states excited by monochromatic synchrotron radiation. The photon energy dependence of the double K-shell ionization was...

Université de Fribourg

Lifetimes of doubly K -shell ionized states

Polasik, M . ; Słabkowska, K . ; Kozioł, K. ; Starosta, J. ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Rzadkiewicz, J.

In: Physica Scripta, 2011, vol. 2011, no. T144, p. 014021

The present work provides a reliable interpretation of the Khα₁/Khα₂ intensity ratios and an explanation of the lifetime values for K-shell hollow atoms based on an advanced theoretical analysis (using extensive multiconfiguration Dirac–Fock calculations with the inclusion of the transverse Breit interaction and quantum electrodynamics...

Université de Fribourg

Establishing nonlinearity thresholds with ultraintense X-ray pulses

Szlachetko, Jakub ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Nachtegaal, Maarten ; Błachucki, Wojciech ; Kayser, Yves ; Sà, Jacinto ; Messerschmidt, Marc ; Boutet, Sebastien ; Williams, Garth J. ; David, Christian ; Smolentsev, Grigory ; Bokhoven, Jeroen A. van ; Patterson, Bruce D. ; Penfold, Thomas J. ; Knopp, Gregor ; Pajek, Marek ; Abela, Rafael ; Milne, Christopher J.

In: Scientific Reports, 2016, vol. 6, p. 33292

X-ray techniques have evolved over decades to become highly refined tools for a broad range of investigations. Importantly, these approaches rely on X-ray measurements that depend linearly on the number of incident X-ray photons. The advent of X-ray free electron lasers (XFELs) is opening the ability to reach extremely high photon numbers within ultrashort X-ray pulse durations and is leading...

Université de Fribourg

Vacuum ultraviolet excitation luminescence spectroscopy of few-layered MoS 2

Pankratov, V ; Hoszowska, Joanna ; Dousse, Jean-Claude ; Huttula, M ; Kis, A ; Krasnozhon, D ; Zhang, M ; Cao, Wei

In: Journal of Physics: Condensed Matter, 2016, vol. 28, no. 1, p. 015301

We report on vacuum ultraviolet (VUV) excited photoluminescence (PL) spectra emitted from a chemical vapor deposited MoS₂ few-layered film. The excitation spectrum was recorded by monitoring intensities of PL spectra at ~1.9 eV. A strong wide excitation band peaking at 7 eV was found in the excitation. The PL excitation band is most intensive at liquid helium temperature and completely...