Application of In-Situ IR-Ellipsometry in Silicon Electrochemistry to Study Ultrathin Films

2018 ◽  
pp. 459-479 ◽  
Author(s):  
Jörg Rappich ◽  
Karsten Hinrichs ◽  
Guoguang Sun ◽  
Xin Zhang
Keyword(s):  
Ultrathin Films ◽  
In Situ Ir

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

In Situ Magnetic-Circular-X-Ray-Dichroism Measurements: An Epitaxial Fe Wedge on Cu(100)

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 41-45 ◽  
Author(s):  
M.E. Dávila ◽  
D. Arvanitis ◽  
J. Hunter Dunn ◽  
N. Mårtensson ◽  
P. Srivastava ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Magnetic Circular Dichroism ◽  
Polarized Light ◽  
Measured Quantity ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Core Electron ◽  
Circularly Polarized ◽  
X Ray

Circularly polarized x-ray radiation is attracting increasing interest as a tool for the characterization of the electronic, magnetic, and chiral properties of low-dimensional structures. Using circular light (with electric field vector parallel to the orbital plane), a dependence of the measured quantity by changing either the orientation of the light polarization or the magnetization is indicative of the existence of magnetic circular dichroism. It can be observed in x-ray absorption spectroscopy (XAS), in which the photon energy is scanned through an absorption threshold exciting a core electron into an unoccupied valence state using circularly polarized light. Synchrotron radiation sources have made this technique possible. It can also be observed in photo-emission spectroscopy from core and valence levels. Here we focus on magnetic circular x-ray dichroism (MCXD) in XAS as an element-specific tool to investigate magnetic properties of ultrathin films in situ. The application of magneto-optical sum rules enables the determination of the orbital and spin magnetic moments per atom from XAS spectra, as well as the easy magnetization direction.MCXD-based magnetometry in XAS is extensively used by measuring the L absorption edges of 3d-transition metals, where large intensity changes (up to 60%) of the L-edge white lines are observed upon reversal of either the sample magnetization or the light helicity. The high magnetic contrast obtained, combined with the elemental specificity of the technique, allows for the study of very dilute samples such as ultrathin films. We first concentrate on the selection rules governing MCXD in XAS.

In Situ IR Spectroscopy for Following the Copolymerization of CO2and Epoxides

2014 ◽  
Vol 86 (9) ◽  
pp. 1627-1628
Author(s):  
K. Böhm ◽  
W. Leitner ◽  
T. E. Müller
Keyword(s):  
Ir Spectroscopy ◽  
In Situ Ir ◽  
In Situ Ir Spectroscopy

In situ IR observation of photo-chemically deposited silicon nitride thin films

1991 ◽  
Vol 48-49 ◽  
pp. 409-413 ◽  
Author(s):  
T. Wadayama ◽  
T. Hihara ◽  
A. Hatta ◽  
W. Suëtaka
Keyword(s):  
Thin Films ◽  
Silicon Nitride ◽  
In Situ Ir

scholarly journals In Situ IR Spectroscopy of Mesoporous Silica Films for Monitoring Adsorption Processes and Trace Analysis

2018 ◽  
Vol 1 (12) ◽  
pp. 7083-7091 ◽  
Author(s):  
Bettina Baumgartner ◽  
Jakob Hayden ◽  
Andreas Schwaighofer ◽  
Bernhard Lendl
Keyword(s):  
Ir Spectroscopy ◽  
Mesoporous Silica ◽  
Trace Analysis ◽  
Silica Films ◽  
In Situ Ir ◽  
Adsorption Processes ◽  
In Situ Ir Spectroscopy

scholarly journals How [FeFe]-Hydrogenase Facilitates Bidirectional Proton Transfer

2019 ◽  
Author(s):  
Moritz Senger ◽  
Viktor Eichmann ◽  
Konstantin Laun ◽  
Jifu Duan ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Amino Acid ◽  
Proton Transfer ◽  
Active Site ◽  
Molecular Hydrogen ◽  
H2 Production ◽  
Amino Acid Residues ◽  
Difference Spectroscopy ◽  
Dynamic Changes ◽  
In Situ Ir

Hydrogenases are metalloenzymes that catalyse the interconversion of protons and molecular hydrogen, H2. [FeFe]-hydrogenases show particularly high rates of hydrogen turnover and have inspired numerous compounds for biomimetic H2 production. Two decades of research on the active site cofactor of [FeFe]-hydrogenases have put forward multiple models of the catalytic proceedings. In comparison, understanding of the catalytic proton transfer is poor. We were able to identify the amino acid residues forming a proton transfer pathway between active site cofactor and bulk solvent; however, the exact mechanism of catalytic proton transfer remained inconclusive. Here, we employ in situ IR difference spectroscopy on the [FeFe]-hydrogenase from Chlamydomonas reinhardtii evaluating dynamic changes in the hydrogen-bonding network upon catalytic proton transfer. Our analysis allows for a direct, molecular unique assignment to individual amino acid residues. We found that transient protonation changes of arginine and glutamic acid residues facilitate bidirectional proton transfer in [FeFe]-hydrogenases.<br>

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