المؤلفون: Chejanovsky, Nathan, Kim, Youngwook, Zappe, Andrea, Stuhlhofer, Benjamin, Taniguchi, Takashi, Watanabe, Kenji, Dasari, Durga Bhaktavatsala Rao, Finkler, Amit, Smet, Jurgen H., Wrachtrup, Jörg

المصدر: Scientific Reports 7, Article number: 14758 (2017)

مصطلحات موضوعية: Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science, Quantum Physics

الوصف: Low-dimensional wide bandgap semiconductors open a new playing field in quantum optics using sub-bandgap excitation. In this field, hexagonal boron nitride (h-BN) has been reported to host single quantum emitters (QEs), linking QE density to perimeters. Furthermore, curvature/perimeters in transition metal dichalcogenides (TMDCs) have demonstrated a key role in QE formation. We investigate a curvature-abundant BN system - quasi one-dimensional BN nanotubes (BNNTs) fabricated via a catalyst-free method. We find that non-treated BNNT is an abundant source of stable QEs and analyze their emission features down to single nanotubes, comparing dispersed/suspended material. Combining high spatial resolution of a scanning electron microscope, we categorize and pin-point emission origin to a scale of less than 20 nm, giving us a one-to-one validation of emission source with dimensions smaller than the laser excitation wavelength, elucidating nano-antenna effects. Two emission origins emerge: hybrid/entwined BNNT. By artificially curving h-BN flakes, similar QE spectral features are observed. The impact on emission of solvents used in commercial products and curved regions is also demonstrated. The 'out of the box' availability of QEs in BNNT, lacking processing contamination, is a milestone for unraveling their atomic features. These findings open possibilities for precision engineering of QEs, puts h-BN under a similar 'umbrella' of TMDC's QEs and provides a model explaining QEs spatial localization/formation using electron/ion irradiation and chemical etching.
Comment: updated abstract

الوصول الحر: http://arxiv.org/abs/1705.00029Test

المؤلفون: Bussmann-Holder, Annette, Roleder, Krystian, Stuhlhofer, Benjamin, Logvenov, Gennady, Lazar, Iwona, Soszyński, Andrzej, Koperski, Janusz, Simon, Arndt, Köhler, Jürgen

مصطلحات موضوعية: Condensed Matter - Materials Science

الوصف: The magneto-optical activity of high quality transparent thin films of insulating EuTiO3 (ETO) deposited on a thin SrTiO3 (STO) substrate with both being non-magnetic materials are demonstrated to be a versatile tool for light modulation. The operating temperature is close to room temperature and admits multiple device engineering. By using small magnetic fields birefringence of the samples can be switched off and on. Similarly, rotation of the sample in the field can modify its birefringence {\Delta}n. In addition, {\Delta}n can be increased by a factor of 4 in very modest fields with simultaneously enhancing the operating temperature by almost 100K.
Comment: 15 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/1609.07905Test

المؤلفون: Bussmann-Holder, Annette, Roleder, Krystian, Stuhlhofer, Benjamin, Logvenov, Gennady, Lazar, Iwona, Soszyński, Andrzej, Koperski, Janusz, Simon, Arndt, Kohler, Jurgen

مصطلحات موضوعية: europium, phase transitions

الوصف: The magneto-optical activity of high quality transparent thin films of insulating EuTiO3 (ETO) deposited on a thin SrTiO3 (STO) substrate, both being non-magnetic materials, are demonstrated to be a versatile tool for light modulation. The operating temperature is close to room temperature and allows for multiple device engineering. By using small magnetic fields birefringence of the samples can be switched off and on. Similarly, rotation of the sample in the field can modify its birefringence Δn. In addition, Δn can be increased by a factor of 4 in very modest fields with simultaneously enhancing the operating temperature by almost 100 K.

العلاقة: Scientific Reports (Nature Publishing Group); Scientific Reports (Nature Publishing Group), Vol. 7 (2017), art. no. 40621; http://hdl.handle.net/20.500.12128/8680Test

الإتاحة: https://doi.org/20.500.12128/8680Test
https://doi.org/10.1038/srep40621Test
https://hdl.handle.net/20.500.12128/8680Test

المؤلفون: Stämmler, Sebastian, Merkle, Rotraut, Stuhlhofer, Benjamin, Logvenov, Gennady, Hahn, Kersten, van Aken, Peter A., Maier, Joachim

المصدر: Solid State Ionics ; volume 303, page 172-180 ; ISSN 0167-2738

مصطلحات موضوعية: Condensed Matter Physics, General Materials Science, General Chemistry

الإتاحة: https://doi.org/10.1016/j.ssi.2017.02.022Test
https://api.elsevier.com/content/article/PII:S0167273816307858?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0167273816307858?httpAccept=text/plainTest

المؤلفون: Berger, Christian, Egger, Andreas, Merkle, Rotraut, Bucher, Edith, Stuhlhofer, Benjamin, Schrödl, Nina, Lammer, Judith, Gspan, Christian, Logvenov, Gennady, Maier, Joachim, Sitte, Werner

المصدر: Journal of The Electrochemical Society; 2019, Vol. 166 Issue 14, pF1088-F1095, 8p

مصطلحات موضوعية: EPITAXY, INDUCTIVELY coupled plasma atomic emission spectrometry, ELECTRON energy loss spectroscopy, SCANNING transmission electron microscopy, ENERGY dispersive X-ray spectroscopy, PULSED laser deposition

مستخلص: Dense thin-film microelectrodes of the first-order Ruddlesden-Popper phases Pr2NiO4+δ (PNO) and Pr2Ni0.9Co0.1O4+δ (PNCO) were prepared by pulsed laser deposition and photolithographic patterning on yttria-stabilized zirconia (YSZ) substrates. The thinfilms were characterized by X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Investigation of the phase stability of PNO and its reactivity with YSZ was performed by X-ray diffraction analyses after high-temperature treatment in air. Resistive and capacitive contributions of the individual processes occurring at the microelectrodes were determined by means of electrochemical impedance spectroscopy at various temperatures (550 ≤ T/°C ≤ 850) and oxygen partial pressures (1 × 10^-3 ≤ pO2/bar ≤ 1). Oxygen surface exchange coefficients kq and kchem were calculated from the surface resistances and chemical capacitances of the thin-film electrodes. Comparing kq-values of PNO and PNCO shows that substitution of Ni with 10% of Co increases the oxygen surface exchange rates, especially at lower oxygen partial pressures. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of The Electrochemical Society is the property of IOP Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Berger, Christian, Egger, Andreas, Merkle, Rotraut, Bucher, Edith, Stuhlhofer, Benjamin, Schrodl, Nina, Lammer, Judith, Gspan, Christian, Logvenov, Gennady, Maier, Joachim, Sitte, Werner

المصدر: Journal of the Electrochemical Society; January 2019, Vol. 166 Issue: 14 pF1088-F1095, 8p

مستخلص: Dense thin-film microelectrodes of the first-order Ruddlesden-Popper phases Pr2NiO4+d (PNO) and Pr2Ni0.9Co0.1O4+d (PNCO) were prepared by pulsed laser deposition and photolithographic patterning on yttria-stabilized zirconia (YSZ) substrates. The thin-films were characterized by X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Investigation of the phase stability of PNO and its reactivity with YSZ was performed by X-ray diffraction analyses after high-temperature treatment in air. Resistive and capacitive contributions of the individual processes occurring at the microelectrodes were determined by means of electrochemical impedance spectroscopy at various temperatures (550 [?] T/degC [?] 850) and oxygen partial pressures (1 x 10[?]3 [?] pO2/bar [?] 1). Oxygen surface exchange coefficients kq and kchem were calculated from the surface resistances and chemical capacitances of the thin-film electrodes. Comparing kq-values of PNO and PNCO shows that substitution of Ni with 10% of Co increases the oxygen surface exchange rates, especially at lower oxygen partial pressures.

المؤلفون: Wedig, Anja, Merkle, Rotraut, Stuhlhofer, Benjamin, Habermeier, Hanns-Ulrich, Maier, Joachim, Heifets, Eugene

المصدر: Physical Chemistry Chemical Physics ; volume 13, issue 37, page 16530 ; ISSN 1463-9076 1463-9084

الإتاحة: https://doi.org/10.1039/c1cp21684hTest
http://pubs.rsc.org/en/content/articlepdf/2011/CP/C1CP21684HTest

المؤلفون: Wang, Lei, Merkle, Rotraut, Cristiani, Georg, Stuhlhofer, Benjamin, Habermeier, Hanns‐Ulrich, Maier, Joachim

المصدر: Zeitschrift für anorganische und allgemeine Chemie ; volume 634, issue 11, page 2087-2087 ; ISSN 0044-2313 1521-3749

الإتاحة: https://doi.org/10.1002/zaac.200870157Test

المؤلفون: Wedig, Anja, Merkle, Rotraut, Stuhlhofer, Benjamin, Habermeier, Hanns-Ulrich, Maier, Joachim, Heifets, Eugene

المصدر: Physical Chemistry Chemical Physics (PCCP); Sep2011, Vol. 13 Issue 37, p16530-16533, 4p

مستخلص: The oxygen incorporation/extraction kinetics of the potential solid oxide fuel cell (SOFC) cathode material Bi1−xSrxFeO3−δwith x= 0.5 and 0.8 was studied by electrochemical impedance spectroscopy on geometrically well-defined pore-free thin film electrodes. The oxygen exchange rate was found to be higher than that of La1−xSrxFeO3−δand—among cobalt-free perovskites—only surpassed by Ba1−xSrxFeO3−δwhich is however known to be unstable in a SOFC environment. [ABSTRACT FROM AUTHOR]

: Copyright of Physical Chemistry Chemical Physics (PCCP) is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Wang, Lei, Merkle, Rotraut, Cristiani, Georg, Stuhlhofer, Benjamin, Habermeier, Ulrich, Maier, Joachim

المصدر: ECS Transactions; December 2008, Vol. 13 Issue: 26 p85-95, 11p

مستخلص: Among the mixed conducting perovskites, (BaxSr1-x)(CoyFe1-y)O3-d (BSCF) attracts special attention due to its exceptionally high effective oxygen incorporation rate constant. The structure of the dense BSCF thin films prepared by pulsed laser deposition (PLD) was investigated. Long-term stability of the cubic perovskite phase for different cation compositions at intermediate temperatures was evaluated. The surface resistance Rs associated with the oxygen incorporation reaction for different cation compositions was determined from impedance spectroscopy measurements on dense thin-film microelectrodes without interference from electrode morphology. The correlation between some bulk properties and Rs was studied.