Combined Pulsed RF GD-OES and HAXPES for Quantified Depth Profiling through Coatings

Chemical characterization at buried interfaces is a real challenge, as the physico-chemical processes operating at the interface govern the properties of many systems and devices. We have developed a methodology based on the combined use of pulsed RF GD-OES (pulsed Radio Frequency Glow Discharge Optical Emission Spectrometry) and XPS (X-ray Photoelectron Spectroscopy) to facilitate the access to deeply buried locations (taking advantage of the high profiling rate of the GD-OES) and perform an accurate chemical diagnosis using XPS directly inside the GD crater. The reliability of the chemical information is, however, influenced by a perturbed layer present at the surface of the crater, hindering traditional XPS examination due to a relatively short sampling depth. Sampling below the perturbed layer may, however, can be achieved using a higher energy excitation source with an increased sampling depth, and is enabled here by a new laboratory-based HAXPES (Hard X-ray PhotoElectron Spectroscopy) (Ga-Kα, 9.25 keV). This new approach combining HAXPES with pulsed RF GD-OES requires benchmarking and is here demonstrated and evaluated on InP. The perturbed depth is estimated and the consistency of the chemical information measured is demonstrated, offering a new route for advanced chemical depth profiling through coatings and heterostructures.

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Layered Double Hydroxide Clusters as Precursors of Novel Multifunctional Layers: A Bottom-Up Approach

Coatings ◽

10.3390/coatings9050328 ◽

2019 ◽

Vol 9 (5) ◽

pp. 328 ◽

Cited By ~ 5

Author(s):

Cristina S. Neves ◽

Alexandre C. Bastos ◽

Andrei N. Salak ◽

Maksim Starykevich ◽

Daisy Rocha ◽

...

Keyword(s):

Layered Double Hydroxide ◽

Photoelectron Spectroscopy ◽

Structural Changes ◽

Optical Emission ◽

Localized Corrosion ◽

Emission Spectrometry ◽

Water Contact ◽

X Ray ◽

Xrd Diffraction ◽

Double Hydroxide

The specific microstructure of aluminum alloys is herein explored to grow spatially-resolved layered double hydroxide (SR-LDH) clusters on their surface. Upon chemical modification of LDHs via intercalation, adsorption and grafting with different functional molecules, novel surface-engineered surfaces were obtained. Crystal structure and phase composition were analyzed by X-ray diffraction (XRD) and surface morphology was observed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectrometry (GDOES) were used to correlate structural changes upon ion-exchange and interfacial modifications with chemical composition and surface profiles of the SR-LDH films, respectively. The protection conferred by these films against localized corrosion was investigated at microscale using the scanning vibrating electrode technique (SVET). LDH-NO3 phase was obtained by direct growth onto AA2024 surface, as evidenced by (003) and (006) XRD diffraction reflections. After anion exchange of nitrate with 2-mercaptobenzothiazole (MBT) there was a decrease in the SR-LDH thickness inferred from GDOES profiles. The subsequent surface functionalization with HTMS was confirmed by the presence of Si signal in XPS and GDOES analyses, leading to an increase in the water contact angle (c.a 144° ± 3°). SVET measurements of the SR-LDH films revealed exceptional corrosion resistance, whereas the bioluminescent bacteria assay proved the anti-microbial character of the obtained films. Overall the results obtained show an effective corrosion protection of the SR-LDHs when compared to the bare substrate and the potential of these films for biofouling applications as new Cr-free pre-treatments.

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Effect of Copper and Annealing Dew Point on Oxidation Behavior of C-Si-Mn Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.286 ◽

2018 ◽

Vol 913 ◽

pp. 286-293

Author(s):

Guang Rui Jiang ◽

Hai Quan Wang ◽

Li Bin Liu

Keyword(s):

Photoelectron Spectroscopy ◽

Oxidation Behavior ◽

Optical Emission ◽

Sem Analysis ◽

Dew Point ◽

Emission Spectrometry ◽

X Ray ◽

External Oxidation ◽

Effect Of Copper ◽

Mn Steel

The effect of copper on oxidation behavior of a C-Si-Mn steel was investigated. The samples were heated to 820°C and held for 75s under four different dew points with 5vol% hydrogen. The results of glow discharge optical emission spectrometry (GDOES), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis techniques revealed the differences in oxidation. It is proposed that the steel containing 0.3 wt.% copper has less external oxidation of silicon and manganese compared to the steel containing no copper for all different dew points. As researched in this paper the external oxidation of C-Si-Mn steels would be suppressed by adding copper.

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PHYSICOCHEMICAL CHARACTERISTICS OF RASAMANIKYA-AN AYURVEDIC ARSENICAL FORMULATION

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2019v11i5.29429 ◽

2019 ◽

pp. 31-36

Author(s):

Arjun Singh ◽

Sarada Ota ◽

Narayanan Srikanth ◽

Galib R ◽

Sreedhar Bojja ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Chemical Characterization ◽

Atomic Emission ◽

Physicochemical Characteristics ◽

Energy Dispersive ◽

Emission Spectrometry ◽

Plasma Atomic Emission Spectrometry ◽

Classical Text ◽

X Ray

Objective: The objective of this study was standardization and Chemical characterization of rasamanikya prepared as per standard operating procedures (SOP) mentioned in the classical text. Methods: Rasamanikya was prepared by putting churnodaka shodhita haratala (Orpiment-As2S3) between two abhraka (white mica) sheets which are heated for a while to obtain a red colored finished product. The Ayurvedic specifications for the analysis of rasamanikya were performed through qualitative and quantitative analysis. Physicochemical analysis, assay of elements by atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were carried out and some other tests such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray analyzer (EDAX) were also performed to ensure the quality of the drug. Results: In the finished drug Arsenic and Sulphur are present in the form of As4S4, As2S3, As2S5. On the basis of XPS survey scans, scanning electron microscopy-energy dispersive x-ray analyzer (SEM-EDAX) and carbon, hydrogen, nitrogen, sulphur (CHNS) analysis the Arsenic to Sulphur (As to S) ratio is thus standardized as 39-47: 53-61. In addition to this powder, XRD shows a major conversion into an amorphous phase. Conclusion: The results could be used to lay down a new set of pharmacopoeial standards for the preparation of rasamanikya for getting optimal efficacy of medicine. Therefore, the information will help the Scientists and Researchers to build comprehensive standards, to screen the compounds responsible for different bioactivities, and to elucidate the molecular mechanism of action.

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The Possibilities for Analytical Methods in Photoemission and Low-Energy Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180495 ◽

1990 ◽

Vol 48 (1) ◽

pp. 348-349

Author(s):

Ernst Bauer

Keyword(s):

Chemical Characterization ◽

Emission Angle ◽

Relative Energy ◽

Objective Lens ◽

Chemical Information ◽

Magnetic Lens ◽

Incident Intensity ◽

X Ray ◽

Leed Pattern ◽

Image Position

One of the major shortcomings of conventional PEEM and of LEEM is the lack of chemical information about the surface. Although the imaging of the LEED pattern in the back focal plane of the objective lens of a LEEM instrument allows chemical characterization via the crystalline structure derived from the LEED pattern, this method fails in the absence of a characteristic LEED pattern. Direct information about the atomic composition of the surface is then needed which can be best obtained from inner shell electrons either directly by x-ray-induced photoemission (XPEEM) or by x-ray- or electron-induced Auger electron emission (AEEM). These modes of excitation and imaging can be combined with conventional PEEM and LEEM in one instrument which is presently being developed. Thus a complete structural and chemical characterization becomes possible in one instrument, with parallel detection and high resolution.In contrast to LEEM, in which up to more than 50% of the incident intensity is available for image formation, the intensity of the emitted electrons is much lower in XPEEM and AEEM and the signal is much lower than the background in AEEM. Therefore, intensity I and resolution d have to be optimized simultaneously which is best done by maximizing Q = I/d2 with respect to maximum emission angle α and relative energy distribution ε = ΔVo/V accepted by the instrument. For a well-designed magnetic lens section of the cathode lens its aberrations are determined by the accelerating field F in front of the specimen. For a homogeneous accelerating field F and a cosine emission distribution one obtains for the optimum α and ε values αo,εo a radius of the minimum disc of confusion of

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The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Catalysts ◽

10.3390/catal11040490 ◽

2021 ◽

Vol 11 (4) ◽

pp. 490

Author(s):

Rudaviro Garidzirai ◽

Phillimon Modisha ◽

Innocent Shuro ◽

Jacobus Visagie ◽

Pieter van Helden ◽

...

Keyword(s):

Electron Microscopy ◽

Inductively Coupled Plasma ◽

Flow Reactor ◽

Plug Flow ◽

Optical Emission ◽

Catalytic Performance ◽

Emission Spectrometry ◽

Hydrogen Yield ◽

X Ray ◽

Temperature Programmed

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

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Chemical characterization of surfaces and interfaces of industrial materials by X-ray photoelectron spectroscopy, Auger electron spectroscopy and secondary ion mass spectrometry

Thin Solid Films ◽

10.1016/0040-6090(80)90552-0 ◽

1980 ◽

Vol 72 (1) ◽

pp. 3-8 ◽

Cited By ~ 2

Author(s):

C.R. Brundle

Keyword(s):

Photoelectron Spectroscopy ◽

Electron Spectroscopy ◽

Auger Electron ◽

Secondary Ion Mass Spectrometry ◽

Chemical Characterization ◽

X Ray ◽

Surfaces And Interfaces ◽

Industrial Materials ◽

Secondary Ion

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Uniform Depth Profiling in X-ray Photoelectron Spectroscopy (Electron Spectroscopy for Chemical Analysis)

Applied Spectroscopy ◽

10.1366/000370278774331468 ◽

1978 ◽

Vol 32 (2) ◽

pp. 175-177 ◽

Cited By ~ 12

Author(s):

L. Bradley ◽

Y. M. Bosworth ◽

D. Briggs ◽

V. A. Gibson ◽

R. J. Oldman ◽

...

Keyword(s):

Chemical Analysis ◽

Auger Electron Spectroscopy ◽

Photoelectron Spectroscopy ◽

Electron Spectroscopy ◽

Auger Electron ◽

Depth Profiling ◽

Ion Source ◽

X Ray ◽

Nitride Oxide ◽

Silicon Device

The difficulties of nonuniform ion etching which hamper depth profiling by X-ray photoelectron spectroscopy (XPS) have been overcome by use of a mechanically scanned saddle-field ion source. The system and its calibration for uniformity are described, and its performance is illustrated by the depth profile of a Si3N4/SiO2/Si metal nitride oxide silicon device. This also allows the potential advantages of XPS profiling over Auger electron spectroscopy profiling to be discussed.

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The effect of cobalt on morphology, structure, and ORR activity of electrospun carbon fibre mats in aqueous alkaline environments

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.12.87 ◽

2021 ◽

Vol 12 ◽

pp. 1173-1186

Author(s):

Markus Gehring ◽

Tobias Kutsch ◽

Osmane Camara ◽

Alexandre Merlen ◽

Hermann Tempel ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Elevated Temperatures ◽

Current Collector ◽

Alkaline Media ◽

Emission Spectrometry ◽

Free Standing ◽

X Ray ◽

Turbostratic Carbon ◽

Current Densities

An innovative approach for the design of air electrodes for metal–air batteries are free-standing scaffolds made of electrospun polyacrylonitrile fibres. In this study, cobalt-decorated fibres are prepared, and the influence of carbonisation temperature on the resulting particle decoration, as well as on fibre structure and morphology is discussed. Scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry are used for characterisation. The modified fibre system is compared to a benchmark system without cobalt additives. Cobalt is known to catalyse the formation of graphite in carbonaceous materials at elevated temperatures. As a result of cobalt migration in the material the resulting overall morphology is that of turbostratic carbon. Nitrogen removal and nitrogen-type distribution are enhanced by the cobalt additives. At lower carbonisation temperatures cobalt is distributed over the surface of the fibres, whereas at high carbonisation temperatures it forms particles with diameters up to 300 nm. Free-standing, current-collector-free electrodes assembled from carbonised cobalt-decorated fibre mats display promising performance for the oxygen reduction reaction in aqueous alkaline media. High current densities at an overpotential of 100 mV and low overpotentials at current densities of 333 μA·cm−2 were found for all electrodes made from cobalt-decorated fibre mats carbonised at temperatures between 800 and 1000 °C.

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CVD Boron Carbo-Nitride as Pore Sealant for Ultra Low-K Interlayer Dielectrics

MRS Proceedings ◽

10.1557/proc-863-b6.8 ◽

2005 ◽

Vol 863 ◽

Cited By ~ 1

Author(s):

P. Ryan Fitzpatrick ◽

Sri Satyanarayana ◽

Yangming Sun ◽

John M. White ◽

John G. Ekerdt

Keyword(s):

Photoelectron Spectroscopy ◽

Depth Profiling ◽

Chemical Vapor ◽

K Value ◽

X Ray ◽

Dimethylamine Borane ◽

The Stability ◽

Low K ◽

Secondary Ion ◽

Sims Depth Profiling

AbstractBlanket porous methyl silsesquioxane (pMSQ) films on a Si substrate were studied with the intent to seal the pores and prevent penetration of a metallic precursor during barrier deposition. The blanket pMSQ films studied were approximately 220 nm thick and had been etched and ashed. When tantalum pentafluoride (TaF5) is exposed to an unsealed pMSQ sample, X-ray photoelectron spectroscopy (XPS) depth profiling and secondary ion mass spectroscopy (SIMS) depth profiling reveal penetration of Ta into the pores all the way to the pMSQ / Si interface. Boron carbo-nitride films were grown by thermal chemical vapor deposition (CVD) using dimethylamine borane (DMAB) precursor with Ar carrier gas and C2H4 coreactant. These films had a stoichiometry of BC0.9N0.07 and have been shown in a previous study to have a k value as low as 3.8. BC0.9N0.07 films ranging from 1.8 to 40.6 nm were deposited on pMSQ and then exposed to TaF5 gas to determine the extent of Ta penetration into the pMSQ. Ta penetration was determined by XPS depth profiling and sometimes SIMS depth profiling. XPS depth profiling of a TaF5 / 6.3 nm BC0.9N0.07 / pMSQ / Si film stack indicates the attenuation of the Ta signal to < 2 at. % throughout the pMSQ. Backside SIMS of this sample suggests that trace amounts of Ta (< 2 at. %) are due to knock-in by Ar ions used for sputtering. An identical film stack containing 3.9 nm BC0.9N0.07 was also successful at inhibiting Ta penetration even with a 370°C post-TaF5 exposure anneal, suggesting the stability of BC0.9N0.07 to thermal diffusion of Ta. All BC0.9N0.07 films thicker than and including 3.9 nm prevented Ta from penetrating into the pMSQ.

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