Radiation Effects Of Vacuum Ultraviolet Laser Photons on Silicon Dioxide

1996 ◽  
Vol 439 ◽  
Author(s):  
K. Kurosawa ◽  
P. R. Herman ◽  
E. Z. Kurmaev ◽  
S. N. Shamin ◽  
V. E. Galakhov ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Emission Spectroscopy ◽  
Radiation Effects ◽  
Vacuum Ultraviolet ◽  
Single Photon ◽  
Photon Absorption ◽  
Bandgap Energy ◽  
Absorption Process ◽  
X Ray ◽  
Emission Studies

AbstractThe argon excimer laser provides 9.8-eV photons that readily surmount the electronic bandgap energy of SiO2 (∼9.0 eV), directly generating excitons in a single-photon absorption process. We have shown by Si L2,3 (Si 3s→2p) X-ray emission spectroscopy, Si 2p X-ray photoelectron spectroscopy and Raman spectroscopy that this absorption process is responsible for silicon precipitation in the silica. The X-ray emission studies further show that the silicon precipitates are crystalline, forming in highest concentration in 120–230 nm layer beneath the laserirradiated surface. Silicon precipitation was not observed on samples irradiated with 146-nm krypton excimer radiation due to a smaller 8.5-eV photon energy that is below the silica bandgap.

FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

2021 ◽  
Vol 11 (5) ◽  
pp. 706-716
Author(s):  
Nada D. Al-Khthami ◽  
Tariq Altalhi ◽  
Mohammed Alsawat ◽  
Mohamed S. Amin ◽  
Yousef G. Alghamdi ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Structural Surface ◽  
Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

Fragmentation of isolated polyatomic molecules induced by vacuum ultraviolet to soft X-ray photon absorption

1990 ◽  
Vol 101 (2-3) ◽  
pp. 273-282 ◽  
Author(s):  
M.-J. Hubin-Franskin ◽  
J. Delwiche ◽  
M. Furlan ◽  
K. Ibrahim ◽  
R. Thissen ◽  
...  
Keyword(s):  
Vacuum Ultraviolet ◽  
Polyatomic Molecules ◽  
Photon Absorption ◽  
X Ray

scholarly journals Determination of 4H-SiC Ionization Rates Using OBIC Based on Two-Photon Absorption

2016 ◽  
Vol 858 ◽  
pp. 245-248 ◽  
Author(s):  
Hassan Hamad ◽  
Christophe Raynaud ◽  
Pascal Bevilacqua ◽  
Sigo Scharnholz ◽  
Bertrand Vergne ◽  
...  
Keyword(s):  
Single Photon ◽  
Green Laser ◽  
Photon Absorption ◽  
Absorption Process ◽  
Field Range ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Avalanche Diodes ◽  
Single Photon Absorption ◽  
Ionization Rates

Optical Beam Induced Current (OBIC) measurements are performed on 4H-SiC avalanche diodes with a very thin and a highly doped active region. A pulsed green laser, with a wavelength of 532 nm, illuminates a reverse biased diode leading to generate electron-hole pairs in the space charge region. Comparison between the 4H-SiC bandgap and the incident photon energy shows that single photon absorption process can be neglected and two-photon absorption process dominates in this case. Ionization rates are then extracted from multiplication curve in a high electric field range (3 to 5 MV.cm–1). Results are in good agreement with previous ones obtained on the same diodes using single photon absorption process.

Development of a high-precision XYZ translator and estimation of beam profile of the vacuum ultraviolet and soft X-ray undulator beamline BL-13B at the Photon Factory

2020 ◽  
Vol 27 (4) ◽  
pp. 923-933
Author(s):  
Yoshihiro Aiura ◽  
Kenichi Ozawa ◽  
Kazuhiko Mase ◽  
Makoto Minohara ◽  
Satoshi Suzuki
Keyword(s):  
High Precision ◽  
Photoelectron Spectroscopy ◽  
Vacuum Ultraviolet ◽  
Chemical Compositions ◽  
X Ray ◽  
Measurement Capability ◽  
Photon Factory ◽  
Experimental Apparatus ◽  
Elemental Analyses ◽  
Microscopic Measurement

A high-precision XYZ translator was developed for the microanalysis of electronic structures and chemical compositions on material surfaces by electron spectroscopy techniques, such as photoelectron spectroscopy and absorption spectroscopy, utilizing the vacuum ultraviolet and soft X-ray synchrotron radiation at an undulator beamline BL-13B at the Photon Factory. Using the high-precision translator, the profile and size of the undulator beam were estimated. They were found to strongly depend on the photon energy but were less affected by the polarization direction. To demonstrate the microscopic measurement capability of an experimental apparatus incorporating a high-precision XYZ translator, the homogeneities of an SnO film and a naturally grown anatase TiO2 single crystal were investigated using X-ray absorption and photoemission spectroscopies. The upgraded system can be used for elemental analyses and electronic structure studies at a spatial resolution in the order of the beam size.

Nitrogen-Doping Induced Optical Bandgap Widening of P-Type Cu2O Flms

2009 ◽  
Vol 1217 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Shu Saeki ◽  
Takeshi Morikawa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Optical Bandgap ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
N Doping ◽  
Hall Effect Measurements ◽  
Optical Bandgap Energy ◽  
P Type

AbstractWe have investigated the effect of N doping into Cu2O films deposited by reactive magnetron sputtering. With increasing N-doping concentration up to 3 at.%, the optical bandgap energy is enlarged from ˜2.1 to ˜2.5 eV with retaining p-type conductivity as determined by optical absorption and Hall-effect measurements. Additionally, photoelectron spectroscopy in air measurements shows an increase in the valence and conduction band shifts with N doping. These experimental results demonstrate possible optical bandgap widening of p-type N-doped Cu2O films, which is a phenomenon that is probably associated with significant structural changes induced by N doping, as suggested from x-ray diffraction measurements.

Observation of atomic-like transition in Sapphire crystal by deep UV photoluminescence spectroscopy

MRS Advances ◽  
2020 ◽  
Vol 5 (35-36) ◽  
pp. 1851-1857
Author(s):  
Nikesh Maharjan ◽  
Mim Lal Nakarmi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Single Photon ◽  
Excitation Power ◽  
Ultraviolet Region ◽  
Composition Analysis ◽  
Sapphire Crystal ◽  
Third Harmonic ◽  
X Ray ◽  
The Third ◽  
Deep Uv

ABSTRACTDeep UV photoluminescence (PL) spectroscopy was employed to study optical properties of a sapphire substrate sample. The sample was photo-excited by the third harmonic laser of a Ti:sapphire pulse laser at wavelength ~ 266 nm which is a below bandgap excitation. In the low temperature (12 K) PL measurement, we observed two sharp atomic-like emissions in the ultraviolet region with peaks at 3.361 eV and 3.315 eV with spectral line-width of 0.85 and 3.30 nm respectively, in the PL spectrum. We performed temperature and power-dependent PL measurements of the sample and observed that the emission peak positions did not change with changing excitation power and sample temperature. We also performed X-ray photoelectron spectroscopy for chemical composition analysis of the sample to explore the origin of the atomic-like emission that could be used for single photon sources for quantum information technology. We will discuss a possible electronic transition and its origin in sapphire.

Electronic Structure of h-WO3 and CuWO4 Nanocrystals, Harvesting Materials for Renewable Energy Systems and Functional Devices

2011 ◽  
Vol 110-116 ◽  
pp. 2188-2193 ◽  
Author(s):  
V.V. Atuchin ◽  
I.B. Troitskaia ◽  
O.Yu. Khyzhun ◽  
V.L. Bekenev ◽  
Yu.M. Solonin
Keyword(s):  
Electronic Structure ◽  
Renewable Energy ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Emission Spectroscopy ◽  
Energy Production ◽  
Energy Systems ◽  
Renewable Energy Systems ◽  
X Ray ◽  
Valence Band Region

— The electronic structure of hexagonal WO3 and triclinic CuWO4 nanocrystals, prospective materials for renewable energy production and functional devices, has been studied using the X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES) methods. The present XPS and XES results render that the W 5d-and O 2p-like states contribute throughout the whole valence-band region of the h-WO3 and CuWO4 nanocrystalline materialls, however maximum contributions of the O 2p-like states occur in the upper, whilst the W 5d-like states in the lower portions of the valence band, respectively.

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