HAFNIUM AND NITROGEN INTERACTION AT Hf/GaN(0001) INTERFACE

2020 ◽  
Vol 27 (11) ◽  
pp. 2050013
Author(s):  
RAFAŁ LEWANDKÓW ◽  
RADOSŁAW WASIELEWSKI ◽  
PIOTR MAZUR
Keyword(s):  
Thermal Treatment ◽  
Photoelectron Spectroscopy ◽  
Molecular Nitrogen ◽  
Native Oxide ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Atomic Nitrogen ◽  
Stable Layer ◽  
Xps Spectra ◽  
X Ray ◽  
Strong Shift

The growth and stability of hafnium films on [Formula: see text]-GaN(0001) surface with native oxide was investigated with X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS). It is shown that hafnium creates a continuous and stable layer on GaN substrate. Thermal treatment at [Formula: see text]C of Hf/GaN system causes decomposition of GaN and reaction of hafnium with atomic nitrogen from the substrate. XPS spectra demonstrate the reaction by a strong shift of the N 1s and Hf 4f lines. An attempt for bringing on the same reaction with molecular nitrogen under pressure of [Formula: see text] mbar was not successful. UPS spectra show a metallic character of the hafnium adlayer in such instances.

Chemical and Mineralogical Characterizations of Cobalt Precursor Recovered from Spent Lithium-Ion Batteries with Incineration Process

2014 ◽  
Vol 878 ◽  
pp. 51-56
Author(s):  
Tao Zhang ◽  
Ya Qun He ◽  
Lin Han Ge ◽  
Hong Li ◽  
Shan Wu
Keyword(s):  
Thermal Treatment ◽  
Lithium Ion Batteries ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Chemical State ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
State Changes ◽  
Incineration Process

The chemical and mineralogical characterizations of cobalt precursor recovered from spent lithium-ion batteries with incineration process was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). It indicates that Co exists in the form of LiCoO2. However, after thermal treatment, complex products including LiCoO2, Co3O4, and Co2AlO4 etc. generated, in which Co3O4 has strong signal. The XPS spectra shows that Li(1-x)CoO2 and LiCoO2 are the main chemical state of Co in the original sample, but after thermal treatment, the chemical state changes to Co3O4. Besides, there are undecomposed Li(1-x)CoO2, CoF3 and Co. Analyses indicate that Co is enriched after thermal treatment and chemical state of some Co have been certified.

scholarly journals Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Valentina Krylova ◽  
Mindaugas Andrulevičius
Keyword(s):  
Photoelectron Spectroscopy ◽  
Copper Sulfide ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Xrd Studies ◽  
Polyamide Film ◽  
Indirect Band Gap ◽  
Xrd Method

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅  solutions and acidified with HCl (0.1 mol⋅) at . After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with ions. It has been established by the XRD method that, beside , the layer contains as well. For PA 6 initially sulfured 4 h, grain size forchalcocite, , was  nm and fordjurleite, , it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 .

Chemical Structures of Native Oxides Formed During Wet Chemical Treatments on NH4F Treated Si(111) Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
Takeo Hattori ◽  
Hiroki Ogawa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Attenuated Total Reflection ◽  
Native Oxide ◽  
X Ray ◽  
Chemical Treatments ◽  
Chemical Structures ◽  
Native Oxides ◽  
Ft Ir ◽  
Wet Chemical ◽  
Silicon Interface

ABSTRACTChemical structures of native oxides formed during wet chemical treatments on NH4F treated Si(111) surfaces were investigated using X-ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared Attenuated Total Reflection(FT-IR-ATR). It was found that the amounts of Si-H bonds in native oxides and those at native oxide/silicon interface are negligibly small in the case of native oxides formed in H2SO4-H2O2-H2O solution. Based on this discovery, it was confirmed that native oxides can be characterized by the amount of Si-H bonds in native oxides. Furthermore, it was found that the combination of various wet chemical treatments with the treatment in NH4OH-H2O2-H2O solution results in the drastic decrease in the amount of Si-H bonds in native oxides.

29Si NMR and XPS Investigation of the Structure of Silicon Oxycarbide Glasses Derived from Polysiloxane Precursors

1994 ◽  
Vol 346 ◽  
Author(s):  
R.J.P. Corriu ◽  
D. Leclercq ◽  
P.H. Mutin ◽  
A. Vioux
Keyword(s):  
Solid State ◽  
Photoelectron Spectroscopy ◽  
Solid State Nmr ◽  
Random Distribution ◽  
Silicon Oxycarbide ◽  
29Si Nmr ◽  
Xps Spectra ◽  
Excess Carbon ◽  
X Ray ◽  
Silicon Oxycarbide Glasses

ABSTRACTTwo silicon oxycarbide glasses with different compositions (O/Si ratio 1.2 and 1.8) were prepared by pyrolysis at moderate temperature (900 °C) of polysiloxane precursors. Their structure was investigated using quantitative 29Si solid-state NMR and X-ray photoelectron spectroscopy (XPS). The environment of the silicon atoms in the oxycarbide phase corresponded to a purely random distribution of Si-O and Si-C bonds depending on the O/Si ratio of the glass only and not on the structure of the precursors. At the light of the NMR results, the Si2p XPS spectra of the glasses may be interpreted using the contribution of the five possible SiOxC4-x tetrahedra. The Cls spectra of these glasses indicated the presence of oxycarbide carbon in CSi4 tetrahedra, similar to carbide carbon, and graphitic-like excess carbon.

Preparation and Characterization of Ni2+-Montmorillonite/Polyvinyl Alcohol Water-Soluble Nanocomposite Film

2005 ◽  
Vol 13 (8) ◽  
pp. 839-846 ◽  
Author(s):  
Li-Ping Wang ◽  
Yun-Pu Wang ◽  
Fa-Ai Zhang
Keyword(s):  
Polyvinyl Alcohol ◽  
Photoelectron Spectroscopy ◽  
Thermal Characteristics ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
Xps Spectra ◽  
X Ray ◽  
Alcohol Water ◽  
Ft Ir ◽  
Silicate Layers

A new type of nano-composite film was prepared from polyvinyl alcohol, Ni2+-montmorillonite (Ni2+-MMT), defoamer, a levelling agent and a plasticizer. Its thermal characteristics were studied by Differential Scanning Calorimetry (DSC). The intermolecular interactions were measured by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the tensile strength (TS) and elongation at break (%E) were measured. The microstructures were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). FT-IR and XPS spectra indicated that cross-linking has taken place between PVA and Ni2+-MMT. XRD and AFM indicate that the PVA molecules had inserted themselves into the silicate layers of MMT, exfoliating them and dispersing them randomly into the PVA matrix. Compared to pure PVA film, the TS of the films was increased and %E decreased when the Ni2+-Montmorillonite was added and the dissolution temperature of the film was also reduced.

scholarly journals Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
D. Mayer ◽  
F. Lever ◽  
D. Picconi ◽  
J. Metje ◽  
S. Alisauskas ◽  
...  
Keyword(s):  
Excited State ◽  
Chemical Shift ◽  
Photoelectron Spectroscopy ◽  
Chemical Shifts ◽  
Excited Molecule ◽  
Charge Motion ◽  
Core Electron ◽  
Xps Spectra ◽  
X Ray ◽  
State Chemical

AbstractThe conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.

Characterization of native oxide film on amorphous Co66Si16B12Fe4Mo2 by X-ray photoelectron spectroscopy

2010 ◽  
Vol 490 (1-2) ◽  
pp. 613-617 ◽  
Author(s):  
Rohit Jain ◽  
Deepika Bhandari ◽  
Anil Dhawan ◽  
S.K. Sharma
Keyword(s):  
Oxide Film ◽  
Photoelectron Spectroscopy ◽  
Native Oxide ◽  
X Ray

Chemical Structure of Native Oxide Grown on Hydrogenterminated Silicon Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
M. Takakura ◽  
T. Yasaka ◽  
S. Miyazaki ◽  
M. Hirose
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pure Water ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Appreciable Amount ◽  
X Ray ◽  
Thermal Oxide ◽  
Phonon Peak ◽  
Strained Bonds

ABSTRACTChemical bonding features and suboxide compositions in native oxide grown on chemically-cleaned hydrogen-terminated Si(100) surfaces stored in pure water have been studied by using surface sensitive infrared spectroscopy and x-ray photoelectron spectroscopy. The LO phonon peak for the native oxide is located at 1210cm−1, which is shifted to a significantly lower wavenumber side than the ultrathin thermal oxide peak at 1250cm−1. This is because an appreciable amount of SiHx bonds are incorporated in the native oxide/Si interface and such hydrogen termination in the network dramatically reduces strained bonds in the interface. Very weak Si2+ suboxide signal from the oxide grown in pure water is also explained by the incorporated SiHx bonds which interrupt the Si2+ suboxide formation in the interface.

X-ray photoelectron spectroscopy characterization of barium titanate ceramics prepared by the citric route. Residual carbon study

1997 ◽  
Vol 12 (9) ◽  
pp. 2388-2392 ◽  
Author(s):  
C. Miot ◽  
E. Husson ◽  
C. Proust ◽  
R. Erre ◽  
J. P. Coutures
Keyword(s):  
Barium Titanate ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Residual Carbon ◽  
Ion Etching ◽  
Xps Spectra ◽  
X Ray ◽  
Titanate Ceramics

Powder and ceramics of barium titanate prepared by the citric process were studied by x-ray photoelectron spectroscopy (XPS). Spectra of C1s, O1s, Ti2p, Ba3d, and Ba4d levels are analyzed in powder and ceramics immediately after the sintering step and after several months of exposure in the air. Ar-ion etching allowed one to characterize the material intrinsic carbon. The results are discussed in comparison with works previously published on oxide single crystals.

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