Epitaxial Waveguiding KNbO3 Thin Films Grown By RF-Sputter Deposition

1994 ◽  
Vol 341 ◽  
Author(s):  
Silvia Schwyn Thöny
Keyword(s):  
Phase Modulation ◽  
Michelson Interferometer ◽  
Sputter Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fundamental Wavelength ◽  
Transmission Electron ◽  
Electro Optic ◽  
20 Nm ◽  
Rf Sputter Deposition

AbstractThe physical and optical properties of KNbO3 layers grown on (001) oriented spinel and MgO substrates by planar rf-sputter deposition were studied. Rutherford Backscattering measurements showed that stoichiometric films could be obtained by using K2CO3 enriched targets and 100% argon as a sputtering gas. The x-ray diffraction spectra showed that single crystalline tetragonal films could be obtained at temperatures in the range of 580–610°C. Furthermore, channelling experiments indicated good crystal quality with a χmin of 40%. High resolution Transmission Electron Microscopy of the films revealed epitaxial growth, but also domains with a typical width of 10–20 nm. Moreover, it was possible to excite waveguide modes with losses of only 1.1 dB/cm at λ = 632.8 nm. The nonlinear optical coefficient d31 was determined by the Maker-fringe technique using the 1.06 μm Nd:YAG laser fundamental wavelength. This yielded a d31 value of 5 pm/V. The electro-optic properties was investigated by phase modulation technique in a Michelson interferometer.

scholarly journals Enhanced Photocatalytic Activity of Vanadium-Doped SnO2 Nanoparticles in Rhodamine B Degradation

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
H. Letifi ◽  
Y. Litaiem ◽  
D. Dridi ◽  
S. Ammar ◽  
R. Chtourou
Keyword(s):  
Photocatalytic Activity ◽  
Rhodamine B ◽  
Crystal Size ◽  
Sno2 Nanoparticles ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
Vanadium Concentration ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm

In this paper, we have reported a novel photocatalytic study of vanadium-doped SnO2 nanoparticles (SnO2: V NPs) in rhodamine B degradation. These NPs have been prepared with vanadium concentrations varying from 0% to 4% via the coprecipitation method. Structural, morphological, and optical properties of the prepared nanoparticles have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), and UV-Vis and photoluminescence (PL) spectroscopy. Structural properties showed that both undoped and SnO2: V NPs exhibited the tetragonal structure, and the average crystal size has been decreased from 20 nm to 10 nm with the increasing doping level of vanadium. Optical studies showed that the absorption edge of SnO2: V NPs showed a redshift with the increasing vanadium concentration. This redshift leads to the decrease in the optical band gap from 3.25 eV to 2.55 eV. A quenching in luminescence intensity has been observed in SnO2: V NPs, as compared to the undoped sample. Rhodamine B dye (RhB) has been used to study the photocatalytic degradation of all synthesized NPs. As compared to undoped SnO2 NPs, the photocatalytic activity of SnO2: V NPs has been improved. RhB dye was considerably degraded by 95% within 150 min over on the SnO2: V NPs.

scholarly journals Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Carmen Steluta Ciobanu ◽  
Simona Liliana Iconaru ◽  
Florian Massuyeau ◽  
Liliana Violeta Constantin ◽  
Adrian Costescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Textural Properties ◽  
Average Crystallite Size ◽  
Luminescent Properties ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vibrational Studies ◽  
20 Nm

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO4)6(OH)2) with0≤x≤0.2nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic5D0→7F0transition observed at 578 nm related to Eu3+ions distributed on Ca2+sites of the apatitic structure.

Nanoporous Ni and Ni-Cu Fabricated by Dealloying

2009 ◽  
Vol 1228 ◽  
Author(s):  
Masataka Hakamada ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Noble Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm ◽  
Good Workability ◽  
Scanning Electron

AbstractMetallic nanoporous architecture can be spontaneously attained by dealloying of a binary alloy. The nanoporous architecture can be often fabricated in noble metals such as Au and Pt. In this study, nanoporous Ni, Ni-Cu are fabricated by dealloying rolled Ni-Mn and Cu-Ni-Mn alloys, respectively. Unlike conventional Raney nickel composed of brittle Ni-Al or Cu-Al intermetallic compounds, the initial alloys had good workability probably because of their fcc crystal structures. After the electrolysis of the alloys in (NH4)2SO4 aqueous solution, nanoporous architectures of Ni and Ni-Cu with pore and ligament sizes of 10–20 nm were confirmed by scanning electron microscopy and transmission electron microscopy. X-ray diffraction analyses suggested that Ni and Cu atoms form a homogeneous solid solution in the Ni-Cu nanoporous architecture. The ligament sizes of nanoporous Ni and Ni-Cu were smaller than that of nanoporous Cu, reflecting the difference between diffusivities of Ni and Cu at solid/electrolyte interface. Ni can reduce the pore and ligament sizes of resulting nanoporous architecture when added to initial Cu-Mn alloys.

The Effect of Collimation On Sputtered Alcusi and Almg Microstructures And Electromigration Failure Characteristics

1993 ◽  
Vol 309 ◽  
Author(s):  
Thomas J. Licata ◽  
Timothy D. Sullivan ◽  
Roy S. Bass ◽  
James G. Ryan ◽  
David B. Knorr
Keyword(s):  
Electron Microscope ◽  
Sputter Deposition ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Failure Characteristics ◽  
X Ray ◽  
Aspect Ratios ◽  
Transmission Electron ◽  
Lower Strain ◽  
Induced Changes

AbstractIncreasing circuit densities produce higher metal wiring aspect ratios, and more difficult feature fill for damascene processing. One method of extending the use of sputter deposition to challenging aspect ratios is to collimate the sputtered flux using a collimator plate, and to avoid randomizing the collimated flux by using low process pressures corresponding to long sputtered atom mean free paths. In this paper, we discuss our fabrication of damascene AI-0.5Cu-2Si and AI-2Mg wiring using both collimated and uncollimated sputtering, and our observations of collimation-induced changes in Al alloy electromigration and microstructure. Our experiments show that collimation has only a small effect on AlCuSi, but a large effect on AIMg. Specifically, the median time to electromigration failure for collimated AIMg was ∼10X the value for uncollimated AlMg and ∼6X the values for collimated and uncollimated AlCuSi. Transmission electron microscope and x-ray diffraction analyses of these films show that the collimation-induced improvement in AIMg t50 is associated with the formation of smaller, lower strain grains which are clustered in very well-oriented (111) domains. We propose that the advantageous AlMg microstructure results from enhanced texture produced by aspects of the collimated deposition active in the absence of incoherent precipitates.

Nanocrystallization of gas atomized Cu47Ti33Zr11Ni8Si1 metallic glass

2006 ◽  
Vol 21 (3) ◽  
pp. 597-607 ◽  
Author(s):  
S. Venkataraman ◽  
S. Scudino ◽  
J. Eckert ◽  
T. Gemming ◽  
C. Mickel ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Primary Crystallization ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
20 Nm ◽  
Annealing Experiments

Cu47Ti33Zr11Ni8Si1 metallic glass powder was prepared by gas atomization. Decomposition in the amorphous alloy and primary crystallization has been studied by differential scanning calorimetry (DSC), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The glassy powder exhibits a broad DSC exotherm prior to bulk crystallization. Controlled annealing experiments reveal that this exotherm corresponds to a combination of structural relaxation and nanocrystallization. A uniform featureless amorphous contrast is observed in the TEM prior to the detection of nanocrystals of 4–6 nm in size. High-resolution TEM studies indicate that this nanocrystalline phase has a close crystallographic relationship with the γ–CuTi phase having a tetragonal structure. The product of the main crystallization event is also nanocrystalline, hexagonal Cu51Zr14, having dimensions of 20 nm. However, there is no evidence for possible amorphous phase separation prior to the nanocrystallization events.

Beryllium-Based Multilayer Structures

1995 ◽  
Vol 382 ◽  
Author(s):  
D. G. Stearns ◽  
K. M. Skulina ◽  
M. Wall ◽  
C. S. Alford ◽  
R. M. Bionta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Normal Incidence ◽  
Sputter Deposition ◽  
Multilayer Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetron Sputter Deposition ◽  
Magnetron Sputter

ABSTRACTMultilayer (ML) structures composed of Mo-Be, Ru-Be and Rh-Be with bilayer periods of - 6 nm have been grown using dc magnetron sputter deposition. The ML microstructure has been characterized using x-ray diffraction and high-resolution transmission electron microscopy, and the normal incidence reflectivity has been measured at soft x-ray wavelengths.

scholarly journals Facile Synthesis of High {001} Facets Dominated BiOCl Nanosheets and Their Selective Dye-Sensitized Photocatalytic Activity Induced by Visible Light

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Da Zhang ◽  
Liang Chen ◽  
Chengjing Xiao ◽  
Jing Feng ◽  
Lingmin Liao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Atmospheric Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Sensitized ◽  
Selective Area ◽  
Transmission Electron ◽  
Organic Surfactant ◽  
20 Nm

Single-crystal BiOCl nanosheets, with high{001}facets exposed, were synthesized through a facile hydrolysis reaction under general atmospheric pressure, without adding any organic surfactant or agent. The thickness of the BiOCl nanosheets is about 20 nm, and the diameter is arranged from 200 to 400 nm. The structure of the BiOCl nanosheets was characterized by X-ray diffraction, energy disperse X-ray spectrum, transmission electron microscopy, and selective area electron diffraction. Moreover, three different dyes were used as model molecules to test the photocatalytic activity of BiOCl nanosheets under visible light. It was found that the BiOCl nanosheets possess selective photocatalytic behavior as their activity over RhB is much higher than that over MO or MB. Based on the analysis of the experimental results, the potential mechanism was discussed.

scholarly journals Cytotoxicity Property of Nano-TiO2Sol and Nano-TiO2Powder

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Pingting He ◽  
Jie Tao ◽  
Jianjun Xue ◽  
Yulan Chen
Keyword(s):  
Electron Microscope ◽  
Average Length ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Experimental Protocols ◽  
20 Nm

A homogeneous and transparent titania (TiO2) sol with nanosized anatase TiO2particles was prepared by hydrothermal synthesis method. The transmission electron microscope and X-ray diffraction were used to characterize the structure and morphology of particulates in the TiO2sol and purchased TiO2powder. The results show that the homogeneous anatase crystalline phase was formed and the size of the spindle-like particle in sol was about 20 nm in width and 150 nm in average length, and the particulates of the purchased powder were globular-like about 50 nm in diameter. In addition, a consistent set of in vitro experimental protocols was used to study the effects of nano-TiO2sol as prepared and nano-TiO2powder on mouse peritoneal macrophage. The cytotoxicity tests in vitro indicate that, with the increasing of TiO2sol concentration contaminated with the cells, the relative proliferation rate of macrophage cells was improved slightly after the cells contaminated for 24 h, but it reduced rapidly after contaminated for 48 h. The purchased nano-TiO2powder inhibited the growth of the cells obviously as cultivating with macrophage both for 24 h and 48 h.

Formation of intermetallic nanocomposites in the Ti–Al–Si system by mechanical alloying and subsequent heat treatment

1998 ◽  
Vol 13 (5) ◽  
pp. 1198-1203 ◽  
Author(s):  
K. W. Liu ◽  
J. S. Zhang ◽  
J. G. Wang ◽  
G. L. Chen
Keyword(s):  
Amorphous Phase ◽  
Titanium Aluminides ◽  
Annealing Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanocrystalline Composites ◽  
Transmission Electron ◽  
Crystallization Reaction ◽  
Different Temperatures ◽  
20 Nm

Formation of nanocrystalline Al3Ti, TiAl, Ti3Al, and Ti5Si3 composites by mechanically alloying (MA) in the Ti–Al–Si system and subsequent annealing treatment are investigated. Microstructure development was monitored by x-ray diffraction, differential thermal analysis, and transmission electron microscopy. An amorphous phase could be generated through milling for 100 h. The results of annealing at different temperatures on this amorphous phase show that the formation of titanium aluminides (Al3Ti, TiAl, and Ti3Al, according to the initial relative amount of Ti and Al) and Ti5Si3 (the only silicide produced by the crystallization reaction) take place. Annealing produces nanocrystalline composites of Al3Ti, TiAl, Ti3Al, and Ti5Si3 with a grain size less than 20 nm. With increasing annealing temperature, the crystalline sizes of the phases increased.

Strontium Hydroxyapatite Synthesis, Characterization and Cell Cytotoxicity

2010 ◽  
Vol 160-162 ◽  
pp. 117-122 ◽  
Author(s):  
Zhi Hong Li ◽  
Ji Min Wu ◽  
Shu Jie Huang ◽  
J. Guan ◽  
Xi Zheng Zhang
Keyword(s):  
Thermal Stability ◽  
Hydrothermal Method ◽  
Bone Repair ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strontium Hydroxyapatite ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Phase Chemical

Strontium hydroxyapatite powders was prepared by the hydrothermal method using Sr(NO3)2 and (NH4)2HPO4 as reagents. Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscope, Energy dispersive X-ray, and Thermogravimetric-differential thermal analysis were employed to investigate the crystalline phase, chemical composition, morphology, and thermal stability of the Strontium hydroxyapatite. And the cytotoxicity of Strontium hydroxyapatite was analyzed through MTT assay. Results showed that Strontium hydroxyapatite prepared by hydrothermal Method has excellent crystal structure, good dispersion, high purity, and rod-like morphology with dimensions 200-500 nm in length and 20 nm in diameter. Meanwhile, the apatite has poor thermal stability. However, the apatite is cytocompatible and may have better biocompatibility, which can serve as strontium source incorporation into calcium phosphate cement and for bone repair.

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