The Interaction of Liquid and Vapor Water with Nearly Defect-Free and Defective TiO2(100) Surfaces

1996 ◽  
Vol 432 ◽  
Author(s):  
Li-Qiong Wang ◽  
P. X. Skiba ◽  
A. N. Shultz ◽  
Don R. Baer ◽  
Mark H. Engelhard
Keyword(s):  
Electron Beam ◽  
Vapor Pressure ◽  
Liquid Water ◽  
Photoelectron Spectroscopy ◽  
Surface Defect ◽  
Photoemission Spectroscopy ◽  
Water Exposure ◽  
Pressure Water ◽  
Adsorption Rates ◽  
Induced Defects

AbstractThe interaction of both liquid and vapor water on nearly defect-free and defective TiO2(100) surfaces has been investigated using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). The study has focused on examining electronic or chemical defects as created in vacuum and after exposure to both liquid and vapor water. Defective surfaces were prepared by electron-beam exposure and Ar+ bombardment. For a nearly defect-free (100)1×1 surface, water coverage was ∼0.02 ML (1ML = 2.9×1015/cm2) at 104 L exposure to low vapor pressure water, ∼0.08 ML at 108 L exposure to higher vapor pressure water, and ∼0.12 ML with liquid water exposure, respectively. Defect intensities were greatly reduced after exposing defective surfaces to ∼102 L low vapor pressure water. More significantly, electron-beam induced defects were completely removed upon higher-pressure vapor exposure (>104 L) or liquid water exposure, while defects created by Ar+ bombardment were only partially removed. The adsorption behavior and surface defect reactivity for TiO2(100) 1×1 surfaces were compared with those for TiO2(110) surfaces. The adsorption rates for nearly defect-free (100) 1×1 and (110) surfaces are comparable. However, the rate of defect “healing” for a defective (100) surface is much faster than that for a defective (110) surface.

The Adsorption of Liquid and Vapor Water on TiO2 (110) Surfaces: The Role of Defects

1994 ◽  
Vol 357 ◽  
Author(s):  
Li-Qiong Wang ◽  
Don R. Baer ◽  
Mark. H. Engelhard
Keyword(s):  
Electron Beam ◽  
Vapor Pressure ◽  
Liquid Water ◽  
Photoelectron Spectroscopy ◽  
Surface Defects ◽  
Water Exposure ◽  
Pressure Water ◽  
Electronic Defects ◽  
Induced Defects

AbstractThe adsorption of liquid and vapor water on defective and nearly defect-free TiO2 (110) surfaces has been examined using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). The study has focused on examining electronic defects as created in vacuum and after exposure to both liquid and vapor water. The defective surfaces were prepared by electron-beam exposure and Ar+ bombardment. With exposure up to 104 L low vapor pressure (<10−5 Torr) water to defective surfaces, little or no changes on Ti 3d defect intensities were observed, in agreement with the previous studies. However, defect intensities were greatly reduced after exposing defective surfaces to ∼ 108 L higher vapor pressure (0.2 - 0.6 Torr) water for 5 min. More significantly, XPS and UPS spectra showed that electron-beam induced defects were completely removed upon liquid water exposure, while defects created by Ar+ bombardment were only partially removed. It was found that surface defects created by Ar+ bombardment were removed more readily than sub-surface defects. For a nearly defect-free surface, water coverages were ∼ 0.02 ML at 104 L exposure to low vapor pressure water, ∼ 0.07 ML at 108 L exposure to higher vapor pressure water, and ∼ 0.125 ML with liquid water exposure, respectively.

scholarly journals Determination of the valence band edge of Fe oxide nanoparticles dispersed in aqueous solution through resonant photoelectron spectroscopy from a liquid microjet

2021 ◽  
Author(s):  
Giorgia Olivieri ◽  
Gregor Kladnik ◽  
Dean Cvetko ◽  
Matthew A. Brown
Keyword(s):  
Aqueous Solution ◽  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Band Edge ◽  
Photoemission Spectroscopy ◽  
Oxide Nanoparticles ◽  
Valence Band Edge ◽  
Resonant Photoemission

The electronic structure of hydrated nanoparticles can be unveiled by coupling a liquid microjet with a resonant photoemission spectroscopy.

Promising Zn3Ta2O8:Pr3+ Red Phosphor for Low Voltage Cathodoluminescence Applications

2011 ◽  
Vol 306-307 ◽  
pp. 251-254 ◽  
Author(s):  
Shreyas S. Pitale ◽  
L.L. Noto ◽  
I.M. Nagpure ◽  
O.M. Ntwaeaborwa ◽  
J.J. Terblans ◽  
...  
Keyword(s):  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
Low Voltage ◽  
Chemical Constituents ◽  
High Energy ◽  
Binding Energies ◽  
Xenon Lamp ◽  
Voltage Electron ◽  
Information Displays ◽  
Prime Concern

Zn3Ta2O8 is a promising host for low voltage cathodoluminescence (CL) applications. Surface chemical stability during low voltage electron beam excitation is a prime concern for phosphors to be used in various new generation information displays. Photoluminescence (PL) and CL characteristics of the Zn3Ta2O8 host doped with Pr3+ are presented. The phosphors were synthesized via solid-state reaction route at 1100°C. Red CL or PL with a maximum at 611 nm, attributed to the 1D2-3H4 transition of the Pr3+ ion, was observed at room temperature under high energy electron (2 keV, 12 μA) or a monochromatic xenon lamp (257 nm) irradiation. Electron stimulated chemical changes on the surface of the Zn3Ta2O8:Pr3+ phosphor during an electron beam exposure from 0-350 C/cm2 was monitored using Auger electron spectroscopy. The CL exhibited only a 20% loss in the original intensity during the continuous electron beam exposure. X-ray photoelectron spectroscopy (XPS) was used to estimate the redox states of the chemical constituents and a comparison of binding energies was made with the standard Ta2O5 and ZnO compounds. A correlation between the structural configuration of Zn3Ta2O8 and the XPS data is also established.

Deposition of Cobalt Doped Zinc Oxide Thin Film Nano-Composites Via Pulsed Electron Beam Ablation

MRS Advances ◽  
2016 ◽  
Vol 1 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Asghar Ali ◽  
Patrick Morrow ◽  
Redhouane Henda ◽  
Ragnar Fagerberg
Keyword(s):  
Zinc Oxide ◽  
Electron Beam ◽  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Oxide Thin Film ◽  
X Ray ◽  
Pulsed Electron Beam ◽  
Deposited Films

AbstractThis study reports on the preparation of cobalt doped zinc oxide (Co:ZnO) films via pulsed electron beam ablation (PEBA) from a single target containing 20 w% Co on sapphire (0001) and silicon (100) substrates. The films have been deposited at various temperatures (350оC, 400оC, 450оC) and pulse frequencies (2 Hz, 4 Hz), under a background argon (Ar) pressure of about 3 mtorr, and an accelerating voltage of 14 kV. The surface morphology has been examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). According to SEM analysis, the films consist of nano-globules whose size is in the range of 80-178 nm. Energy dispersive x-ray spectroscopy (EDX) reveals that deposition is congruent and the prepared films contain ∼20±5 w% cobalt. It has been found that the nano-globules in the deposited films are cobalt-rich zones containing ∼70 w% Co. From x-ray photoelectron spectroscopy (XPS) analysis, Co 2p3/2 peaks indicate that the deposited films contain CoO (binding energy = 780.5 eV) as well as metallic Co (binding energy = 778.1-778.5 eV). X-ray diffraction (XRD) analysis supports the presence of metallic Co hcp phase (2ϴ = 44.47° and 47.43°) in the films.

Temperature Dependence of Surface Morphology of Silicon Grown on CaF2/Si by Electron Beam Assisted Mbe

1994 ◽  
Vol 367 ◽  
Author(s):  
P.O. Pettersson ◽  
R.J. Miles ◽  
T.C. Mcgill
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
Silicon Layer ◽  
Surface Damage ◽  
Low Energy ◽  
Growth Mode ◽  
Optimal Range ◽  
Low Energy Electrons ◽  
Ordered Array

AbstractWe present the results of electron beam assisted molecular beam epitaxy (EB-MBE) on the growth mode of silicon on CaF2/Si(111). By irradiating the CaF2 surface with low energy electrons, the fluorine is desorbed, leaving an ordered array of F-centers behind. Using atomic force microscopy (AFM), we do not detect any surface damage on the CaF2 layer due to the low energy electron irradiation. The surface free energy of the CaF2 is raised due to the F-center array and the subsequent silicon layer is smoother. Using AFM and X-ray photoelectron spectroscopy (XPS), we find an optimal range of exposures for high temperature (650°C) growth of the silicon overlayer that minimizes surface roughness of the silicon overlayer and we present a simple model based on geometrical thermodynamics to explain this.We observed a similar optimal range of exposures that minimizes the surface roughness for medium (575°C) and low (500°C) growth temperatures of the silicon layer. We present an explanation for this growth mode based on kinetics.

scholarly journals Electrical characterization of electron beam exposure induced defects in epitaxially grown n-type silicon

2019 ◽  
Author(s):  
H. T. Danga ◽  
F. D. Auret ◽  
S. M. Tunhuma ◽  
E. Omotoso ◽  
E. Igumbor ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electrical Characterization ◽  
Type Silicon ◽  
Induced Defects

Evaluation of Corrections for X-Ray Microanalysis in the ESEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 698-699
Author(s):  
Robert A. Carlton ◽  
Charles E. Lyman ◽  
James E. Roberts ◽  
Raynald Gauvin
Keyword(s):  
Electron Beam ◽  
Vapor Pressure ◽  
Path Length ◽  
High Vacuum ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
X Ray ◽  
Scattering Effects ◽  
Beam Scattering ◽  
The Relationship

A number of methods have been proposed to correct for the electron beam scattering effects on xray microanalysis in the environmental scanning electron microscope (ESEM). This paper presents an evaluation of two of these methods. The Doehne method is based on the observation that x-ray counts due to the unscattered electron beam increase with decreasing chamber pressure whereas the inverse is true for x-ray counts due to scattered electrons. The x-ray count intercept, at zero pressure, of the regression lines relating x-ray counts to chamber vapor pressure is an estimate of the high-vacuum intensity. The Gauvin method is based on the relationship between x-ray counts and the fraction of the electron beam that is unscattered, fp.The fraction of the unscattered beam is calculated using an equation derived from scattering theory and uses the accelerating voltage, the gas path length, and the chamber vapor pressure.

Flame-retardant cotton fabrics modified with phosphoramidate derivative via electron beam irradiation process

2019 ◽  
pp. 152808371988181
Author(s):  
Ying Liu ◽  
Li Zhou ◽  
Fang Ding ◽  
Shanshan Li ◽  
Rong Li ◽  
...  
Keyword(s):  
Electron Beam ◽  
Flame Retardant ◽  
Photoelectron Spectroscopy ◽  
Electron Beam Irradiation ◽  
Cotton Fabrics ◽  
Beam Irradiation ◽  
Limiting Oxygen Index ◽  
Flammability Test ◽  
Lower Temperature ◽  
Irradiation Process

In this study, a novel flame-retardant diethyl methacryloylphosphoramidate containing phosphorus and nitrogen was synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance. The synthesized compound was grafted onto cotton fabrics using electron beam irradiation and pad dry cure processes. Scanning electron microscope and X-ray photoelectron spectroscopy were used to characterize the surfaces of the modified cotton fabrics to confirm that diethyl methacryloylphosphoramidate was grafted on cotton fabrics successfully. Both electron beam–cotton and pad dry cure–cotton exhibited efficient flame retardancy which was proved by limiting oxygen index and vertical flammability test. Thermogravimetric analysis results showed that both electron beam-cotton and pad dry cure–cotton degraded at lower temperature and produced higher yields at 600℃. The tensile loss of electron beam–cotton was lower than that of pad dry cure–cotton, and within the acceptable range in flame retardant finishing.

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