Kinetics of electron-hole recombination in X-ray irradiated cubic stabilized zirconia

1996 ◽  
Vol 116 (1-4) ◽  
pp. 191-194 ◽  
Author(s):  
C.B. Azzoni ◽  
L. Bolis ◽  
A. Paleari
Keyword(s):  
Stabilized Zirconia ◽  
Electron Hole ◽  
X Ray ◽  
Kinetics Of ◽  
Hole Recombination

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

CeO2/TiO2 Nanotubes Composites: Synthesis, Characterization, and Photocatalytic Properties

2012 ◽  
Vol 583 ◽  
pp. 86-90 ◽  
Author(s):  
Hai Bin Li ◽  
Xin Yong Li ◽  
Yan De Song ◽  
Shu Guang Chen ◽  
Ying Wang ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Electron Hole ◽  
Calcination Process ◽  
X Ray ◽  
Transmission Electron ◽  
Hole Recombination

TiO2nanotubes were prepared via a hydrothermal route. CeO2nanoparticles with diameters around 5nm were loaded onto the surface of TiO2nanotubes via a deposition approach followed by a calcination process. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (UV-vis) were applied for the characterization of the as-prepared CeO2/TiO2nanotubes composites. The results show that CeO2particles are highly dispersed on the surface of TiO2nanotubes. The TiO2 nanotubes are modified to response to the visible light due to the combination with CeO2. The CeO2/TiO2nanotubes composites with a CeO2/TiO2atomic ratio of 2.5% show a further improvement on the photocatalytic activity for degradation of Rhodamine B in water. The presence of CeO2improves the light absorption of TiO2nanotubes and inhibits the electron-hole recombination.

Synchrotron X-Ray Topographic Studies of Recombination Activated Shockley Partial Dislocations in 4H-Silicon Carbide Epitaxial Layers

2008 ◽  
Vol 600-603 ◽  
pp. 357-360 ◽  
Author(s):  
Yi Chen ◽  
Xian Rong Huang ◽  
Ning Zhang ◽  
Michael Dudley ◽  
Joshua D. Caldwell ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Epitaxial Layers ◽  
Threading Dislocations ◽  
X Rays ◽  
Electron Hole ◽  
X Ray ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Edge Component ◽  
Hole Recombination

Electron-hole recombination activated Shockley partial dislocations bounding expanding stacking faults and their interactions with threading dislocations have been studied in 4H-SiC epitaxial layers using synchrotron x-ray topography. The bounding partials appear as white stripes or narrow dark lines in back-reflection X-ray topographs recorded using the basal plane reflections. Such contrast variations are attributable to the defocusing/focusing of the diffracted X-rays due to the edge component of the partial dislocations, which creates a convex/concave distortion of the basal planes. Simulation results based on the ray-tracing principle confirm our argument. The sign of the partial dislocations can be subsequently determined.

scholarly journals Luminescence of CsI and CsI:Na Films under LED and X-ray Excitation

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 751
Author(s):  
Jin-Cherng Hsu ◽  
Yu-Shen Ma
Keyword(s):  
Broad Band ◽  
Cesium Iodide ◽  
Exciting Light ◽  
Electron Hole ◽  
X Ray ◽  
New Energy ◽  
Section Surface ◽  
Surface Morphologies ◽  
Deposited Films ◽  
Hole Recombination

In this study, we investigated the luminous properties of undoped cesium iodide (CsI) and Na-doped CsI (CsI:Na) films deposited by thermal vacuum evaporation and treated with different substrate temperatures, post-annealing temperatures, and deposition rates. The quality of the deposited films was evaluated by their XRD pattern, SEM cross-section/surface morphologies and UV/X-ray luminescence, the spectra of which were used to derive the luminescence mechanism of the deposited films. The 310 nm luminescence demonstrates that the exciting light arises from the electron–hole recombination through the self-trapped exciton (STE) process, which is characteristic of the host polycrystalline CsI. The broad-band luminescence from ~400 to 450 nm demonstrates the other electron–hole recombination between the new energy states created by doping Na in the forbidden gap of CsI. When we deposited higher quality films at a substrate temperature of 200 °C, the undoped CsI films showed preferred crystal orientation at (200), and the CsI:Na films co-evaporated by 1 wt.% NaI at (310) and had the highest UV/X-ray luminescence.

Kinetics of indirect electron-hole recombination in a wide single quantum well in a strong electric field

JETP Letters ◽  
2006 ◽  
Vol 84 (4) ◽  
pp. 222-225 ◽  
Author(s):  
V. V. Solov’ev ◽  
I. V. Kukushkin ◽  
J. H. Smet ◽  
K. von Klitzing ◽  
W. Dietsche
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Strong Electric Field ◽  
Single Quantum ◽  
Electron Hole ◽  
Single Quantum Well ◽  
Kinetics Of ◽  
Hole Recombination

Preparation of polyaniline modified BiOBr with enhanced photocatalytic activities

2017 ◽  
Vol 10 (04) ◽  
pp. 1750040 ◽  
Author(s):  
Xiaoyun Hao ◽  
Junyan Gong ◽  
Lizhen Ren ◽  
Dongen Zhang ◽  
Xin Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diffuse Reflectance ◽  
Photocatalytic Properties ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Photocatalytic Activities ◽  
Hole Recombination ◽  
Scanning Electron

The polyaniline/bismuth oxybromide (PANI/BiOBr) hybrids materials have been synthesized hydrothermally in the presence of PANI. The PANI/BiOBr hybrids materials were confirmed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy and ultraviolet–visible diffuse reflectance spectroscopies. Among the hybrid photocatalysts, PANI/BiOBr-0.2 showed the highest photocatalytic properties for the degradation of rhodamine B (RhB), and the increased photocatalytic properties could be due to photosensitization and the inhibited electron–hole recombination.

Synthesis of Polyaniline-TiO2 Nanocomposites and Their Application in Photocatalytic Degradation

2017 ◽  
Vol 25 (7) ◽  
pp. 507-514 ◽  
Author(s):  
Nur Aziera Jumat ◽  
Phang Sook Wai ◽  
Juan Joon Ching ◽  
Wan Jefrey Basirun
Keyword(s):  
Visible Light ◽  
Chemical Structure ◽  
Reactive Black 5 ◽  
Great Efficiency ◽  
Electron Hole ◽  
X Ray ◽  
Photocatalytic Application ◽  
Template Free ◽  
Low Efficiency ◽  
Hole Recombination

Photocatalyst involving conducting polymer doped with titanium dioxide, TiO2 hold a great efficiency for photocatalytic application. In present study, polyaniline (PAni) with different TiO2 content (10%, 20%, and 40%) has been successfully synthesized through template free method. Ultraviolet-visible (UV-vis), Fourier Transform Infrared (FTIR), Raman, and X-ray Powder Diffraction (XRD) characterizations of PAni-TiO2 nanocomposites confirmed the chemical structure of polymer composites was intact after doped with TiO2. Field Emission Scanning Electron Microscope (FESEM) investigation of PAni-TiO2 nanocomposites revealed the formation of nanorod/nanotube. PAni-TiO2(10%) showed the highest conductivity 2.48 × 10−2 S/cm as compared to those with 20% and 40% of TiO2 content. Photocatalytic properties of PAni-TiO2 were examined by degrading Reactive Black 5 (RB5) dye under visible light irradiation. PAni-TiO2(10%) showed the greatest degradation (96%) than that of TiO2 (10%). Due to synergistic effect between PAni and TiO2, it is capable of absorbing visible light more efficiently and decreasing the process of electron hole recombination. Photoluminescence (PL) analysis proved low efficiency of electron hole recombination of PAni-TiO2.

Determination of the Core-structure of Shockley Partial Dislocations in 4H-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Yi Chen ◽  
Ning Zhang ◽  
Xianrong Huang ◽  
Joshua D Caldwell ◽  
Kendrick X Liu ◽  
...  
Keyword(s):  
Contrast Variation ◽  
Electron Hole ◽  
X Ray ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Bipolar Devices ◽  
Simulation Based ◽  
Hole Recombination

ABSTRACTSynchrotron x-ray topographs taken using basal plane reflections indicate that the electron-hole recombination activated Shockley partial dislocations in 4H silicon carbide bipolar devices appear as either white stripes with dark contrast bands at both edges or dark lines. In situ electroluminescence observations indicated that the mobile partial dislocations correspond to the white stripes in synchrotron x-ray topographs, while immobile partial dislocations correspond to the dark lines. Computer simulation based on ray-tracing principle indicates that the contrast variation of the partial dislocations in x-ray topography is determined by the position of the extra atomic half planes associated with the partial dislocations lying along their Peierls valley directions. The chemical structure of the Shockley partial dislocations can be subsequently determined unambiguously and non-destructively.

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