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Chemical state

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


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TL;DR: In this article, the double insulating layer consisting of anodic oxide grown in H 2 O 2 electrolyte and thermally evaporated ZnS film was formed for HgCdTe metal−insulator−semiconductor (MISr) structure in connection with the improvement of surface passivation, and the chemical compositions investigated by energy dispersive spectroscopy (EDSr) using TEM and XPS measurements of depth composition profile and Zn chemical state indicated that the interface layer is composed of ZnO.

6 citations

Journal ArticleDOI
TL;DR: Effects of magnesium on phosphorus chemical states and p-type conduction behavior of phosphorus-doped ZnO (ZnO:P) films were investigated by combining experiment with first-principles calculation, well supporting the experiments from the PL spectra and XPS measurements.
Abstract: Effects of magnesium on phosphorus chemical states and p-type conduction behavior of phosphorus-doped ZnO (ZnO:P) films were investigated by combining experiment with first-principles calculation. Photoluminescence (PL) spectra show that Mg incorporation increases the amount of VZn, which makes more PZn-2VZn complex acceptor formed and background electron density decreased, leading to that MgZnO:P exhibits better p-type conductivity than ZnO:P. The p-type conductivity mainly arises from PZn-2VZn complex acceptor with a shallow acceptor energy of 108 meV. X-ray photoelectron spectroscopy (XPS) spectra reveal that phosphorus has two chemical states of PZn-2VZn complex and isolated PZn, with binding energy of P2p3/2 of 132.81 and 133.87 eV, respectively. The conversion of isolated PZn to PZn-2VZn complex induced by Mg incorporation is observed in XPS, in agreement with the PL results. First-principles calculations suggest that the formation energy of nMgZn-VZn complex decreases with the increasing Mg content...

6 citations

Journal ArticleDOI
TL;DR: The correlation with the deepest 1s energy level evidences that the element specificity of o-Ps originates from pick-off annihilation with orbital electrons, i.e., dominantly with oxygen 2p valence electrons and s electrons with lower probability.
Abstract: Momentum distributions associated with ortho-positronium (o-Ps) pick-off annihilation photon are often influenced by light elements, as, e.g., carbon, oxygen, and fluorine. This phenomenon, so-called element specificity of o-Ps pick-off annihilation, has been utilized for studying the elemental environment around the open spaces. To gain an insight into the element specificity of o-Ps pick-off annihilation, the chemical shift of oxygen 1s binding energy and the momentum distributions associated with o-Ps pick-off annihilation were systematically investigated for alkali-metal loaded SiO2 glasses by means of X-ray photoelectron spectroscopy and positron-age-momentum correlation spectroscopy, respectively. Alkali metals introduced into the open spaces surrounded by oxygen atoms cause charge transfer from alkali metals to oxygen atoms, leading to the lower chemical shift for the oxygen 1s binding energy. The momentum distribution of o-Ps localized into the open spaces is found to be closely correlated with the oxygen 1s chemical shift. This correlation with the deepest 1s energy level evidences that the element specificity of o-Ps originates from pick-off annihilation with orbital electrons, i.e., dominantly with oxygen 2p valence electrons and s electrons with lower probability.

6 citations

Journal ArticleDOI
TL;DR: Reflected electron energy loss microscopy and scanning Auger microscopy (SAM) are used to highlight lateral and vertical chemical changes at the interface between atomically clean silicon and oxidized/contaminated silicon surfaces as discussed by the authors.

5 citations

Journal ArticleDOI
TL;DR: In this paper, in situ soft X-ray scanning microscopy electrochemical study of model proton exchange cathodic and anodic nano-fuel cells is explored the evolving structure and chemical composition of key cell components represented by Au and Fe electrodes in contact with Nafion-ionic liquid composite electrolyte containing Pt black catalyst particles.
Abstract: This in situ soft X-ray scanning microscopy electrochemical study of model proton exchange cathodic and anodic nano-fuel cells is exploring the evolving structure and chemical composition of key cell components represented by Au and Fe electrodes in contact with Nafion-ionic liquid composite electrolyte containing Pt black catalyst particles. Morphological and chemical changes of the electrodes as well as the chemical state and fate of the Fe species released into the electrolyte are monitored in short circuit and with applied cathodic or anodic polarization. The in situ X-ray absorption images of the cathodic cell fed with 2.5 × 10–5 mbar O2 have revealed corrosion-induced morphology changes in the Fe electrode, being more pronounced in the vicinity of Pt-black particles, and deposition of the Fe species released into the electrolyte, onto the intact Au counter electrode upon cathodic polarization. The Fe electrodes of the anodic cell containing NaBH4 in the electrolyte appear relatively more corrosion resistant. The Fe L3 absorption spectra taken in different locations within the Fe electrode have shown lateral variations in the relative ratio between Fe2+ and Fe3&4+ oxidation states, whereas the Fe species released into the RTIL electrolyte are only in the high Fe3&4+ oxidation states.

5 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202184
202089
201987
201894