Chemical state

About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.

Surface core-level shifts of strontium observed in photoemission of barium strontium titanate thin films

Abstract: Angle resolved x-ray photoelectron spectroscopy was used to investigate the surface electronic structure of barium strontium titanate (BST) films. In contrast to previous photoemission studies which identified two chemical states associated with only Ba in the near surface region, the authors have resolved core-level features from surface Sr atoms which provide new insight into the surface electronic structure of BST thin films. The surface Sr 3d features are found to lie approximately 1eV higher in binding energy than the bulk derived peaks. The effects of aqueous and annealing surface treatments and the origin of the Sr surface core-level shifts are discussed.

Use of an Auger parameter for characterizing the Mg chemical state in different materials

Abstract: Metallic, oxide and hydroxide environments of magnesium are clearly identified by X-ray photoelectron spectroscopy from chemical shift of Mg 1s and Mg 2p photopeaks. Unfortunately, Mg3N2 cannot be distinguished from MgO through these two peaks. In this work, we give evidence that it is possible to unambiguously identify magnesium nitride from magnesium oxide thanks to a Mg Auger parameter defined as the difference between the kinetic energy (KE) of the Mg K L L Auger peak and the KE of the Mg 1s peak. The value obtained for Mg3N2 (1000.0 eV) is quite different from the one observed for MgO (998.6 eV). Values obtained for metallic Mg and for Mg(OH)2 are, respectively, equal to 1004.2 and 997.5 eV. This parameter is then used in order to characterize the modification of the Mg chemical environment in the Al-5083 aluminum alloy (containing 4.5 at.% Mg) nitrided by a distributed electron cyclotron resonance nitrogen plasma.

Direct synthesis and structural analysis of nitrogen-doped carbon nanofibers.

Abstract: Carbon nanofibers containing a range of nitrogen contents of 1−10 atom % were directly synthesized by catalytic chemical vapor deposition over nickel-based catalysts at 350−600 °C using acetonitrile and acrylonitrile. The nitrogen content was controlled by careful choice of the reaction conditions. The N-doped carbon nanofibers showed herringbone structure with 20−60 nm diameter. X-ray photoelectron spectroscopy was applied to examine the chemical state of nitrogen in carbon nanofibers. Structural features of N-doped carbon nanofibers were examined in X-ray diffraction and electron microscopy. The mechanism for nitrogen including the structure of carbon nanofibers through the catalysis was discussed on the basis of the results.

Role of Co-W Interaction in the Selective Growth of Single-Walled Carbon Nanotubes from CO Disproportionation

Abstract: A combination of characterization techniques has been employed to obtain a full description of the structure and chemical state of a series of Co−W/SiO2 catalysts used for the production of single-...

Si 2p XPS spectrum of the hydrogen‐terminated (100) surface of device‐quality silicon

Abstract: An experimental study of the Si 2p XPS spectrum at different take-off angles of atomically flat, hydrogen-terminated 1 × 1 Si(100) is reported. The observed spectrum can be described accurately by considering three additional contributions to the spectrum of elemental silicon. Each contribution is attributed to a chemical state of silicon on the basis of its chemical shift with respect to elemental silicon and the depth of the region where it was originated. Copyright © 2003 John Wiley & Sons, Ltd.