Epitaxial growth of Co/Cu[100] and [111] superlattices via rf sputtering on sapphire (1120)-substrates

1994 ◽  
Vol 9 (3) ◽  
pp. 570-581 ◽  
Author(s):  
Ch. Morawe ◽  
A. Abromeit ◽  
N. Metoki ◽  
P. Sonntag ◽  
H. Zabel
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Rf Sputtering ◽  
Growth Direction ◽  
Substrate Orientation ◽  
Careful Choice ◽  
X Ray ◽  
Transmission Electron ◽  
Average Lattice

Co/Cu superlattices with total thicknesses ranging from 10 nm to 60 nm and with periodicities of 1.6–8.5 nm were sputtered on single-crystalline sapphire (1120)-substrates. Sputtering with low rates at room temperature yields samples of high epitaxial and crystalline quality. By careful choice of the sputtering parameters, either the fee [100] or the fcc [111] orientation can be selected as growth direction on one and the same substrate orientation. The preference for a particular film orientation appears to be kinetically driven. In all cases, the average lattice spacings d and the appearance of satellite reflections in x-ray Bragg-scans point to coherent growth up to thicknesses of 30 nm. X-ray small angle reflectivity measurements reveal clear oscillations and satellites indicative for smooth interfaces. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations supplement the characterization of the films.

Preparation and Characterization of Monodisperse Ceria Microspheres

2010 ◽  
Vol 434-435 ◽  
pp. 850-852
Author(s):  
Qi Wang ◽  
Bo Yin ◽  
Zhen Wang ◽  
Gen Li Shen ◽  
Yun Fa Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Electron Microscope ◽  
Crystalline Form ◽  
X Ray ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Scanning Electron

In present work, ceria microspheres were synthesized by template hydrothermal method. Crystalline form of the as-synthesized ceria microspheres was defined by X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Dispersibility of ceria microspheres was comprehensively characterized using scanning electron microscope (SEM) observation and laser particle size analyzer. Furthermore, the ultraviolet light absorption performances of ceria microspheres with several different sizes were compared by ultraviolet visible spectrophotometer. The results showed that ceria microspheres presented excellent UV absorbent property and the size influence was remarkable.

Preparation and Characterization of Cu-SiO2 Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 255-258 ◽  
Author(s):  
Young Hwan Kim ◽  
Beong Gi Jo ◽  
Jee Hean Jeong ◽  
Young Soo Kang
Keyword(s):  
Silica Nanoparticles ◽  
Room Temperature ◽  
Sio2 Nanoparticles ◽  
Hybrid Structures ◽  
Cu Nanoparticles ◽  
Stöber Method ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrolysis And Condensation

A room temperature route for doping silica particles with Cu nanoparticles to achieve hybrid structures is introduced. First, silica nanoparticles were synthesized according to the well-known Stöber method by hydrolysis and condensation of TEOS in a mixture of ethanol with water, using ammonia as catalyst to initiate the reaction. These SiO2 nanoaprticles were dried at 100 oC. We measured the size of these nanoparticles with transmission electron microscopy (TEM). Second, Cu-SiO2 nanoparticles were synthesized by reaction with CuCl2 and SiO2 nanoparticles in presence of catalyst at room temperature for 12 hrs. Results show silica nanoparticles of about 70 nm size with regularly deposited Cu nanoparticles. Cu-SiO2 nanoparticles were investigated with TEM images, energy dispersive X-ray analysis (EDX) spectrum and so on.

scholarly journals Characterization of Pd Impurities and Finite-Sized Defects in Detector Grade CdZnTe

2011 ◽  
Vol 1341 ◽  
Author(s):  
M.C. Duff ◽  
J.P. Bradley ◽  
Z.R. Dai ◽  
N. Teslich ◽  
A. Burger ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cubic Phase ◽  
Secondary Phases ◽  
Detector Performance ◽  
X Ray ◽  
Metal Impurities ◽  
Transmission Electron ◽  
Large Numbers ◽  
Topographic Imaging

ABSTRACTSynthetic CdZnTe or “CZT” crystals are highly suitable for γ-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined “finite-sized” planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

SYNTHESIS AND CHARACTERIZATION OF BIFUNCTIONAL CoFe2O4–ZnS NANOCOMPOSITE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 237-240 ◽  
Author(s):  
J. P. BORAH ◽  
C. BORGOHAIN ◽  
K. C. SARMA ◽  
K. K. SENAPATI ◽  
P. PHUKAN
Keyword(s):  
Drug Targeting ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Magnetic Nanomaterials ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Magnetic Fluid Hyperthermia ◽  
X Ray ◽  
Transmission Electron

The synthesis of composite magnetic nanomaterials has received increasing attention due to their electronic, magnetic, catalytic, and chemical or biological sensing properties. We have prepared cobalt ferrite–zinc sulfide nanocomposites by a chemical route. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and photoluminescence spectrometer (PL). The fluorescent magnetic nanoparticles (FMNPs) had a typical diameter of 30±5 nm and saturation magnetization of 5.8 emu g-1 at room temperature. So, these FMNPs may be potentially applied in different fields such as optoelectronic devices, biolabeling, imaging, drug targeting, bioseparation, magnetic fluid hyperthermia, etc.

scholarly journals Characterization of individual stacking faults in a wurtzite GaAs nanowire by nanobeam X-ray diffraction

2017 ◽  
Vol 24 (5) ◽  
pp. 981-990 ◽  
Author(s):  
Arman Davtyan ◽  
Sebastian Lehmann ◽  
Dominik Kriegner ◽  
Reza R. Zamani ◽  
Kimberly A. Dick ◽  
...  
Keyword(s):  
Bragg Peak ◽  
Stacking Faults ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Patterson Function ◽  
Transmission Electron ◽  
Gaas Nanowires ◽  
Gaas Nanowire

Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the [000\bar{1}] direction in the vicinity of the wurtzite 00\bar{1}\bar{5} Bragg peak. The maxima of the Patterson function encode both the distances between the fault planes and the type of the fault planes with the sensitivity of a single atomic bilayer. The positions of the fault planes are deduced from the positions and shapes of the maxima of the Patterson function and they are in excellent agreement with the positions found with transmission electron microscopy of the same nanowire.

Solvothermal Synthesis and Characterization of Lithium Tantalate Nanoparticles

2014 ◽  
Vol 602-603 ◽  
pp. 19-22 ◽  
Author(s):  
Lin Qiang Gao ◽  
Hai Yan Chen ◽  
Zhen Wang ◽  
Xin Zou
Keyword(s):  
Electron Microscopy ◽  
Solvothermal Synthesis ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Particle Size And Morphology ◽  
Size And Morphology

Nanoscale LiTaO3 powders with perovskite structure were synthesized using the solvothermal technique with glycol as solvent at 240°C for 12h. The powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD was used to elucidate room temperature structures using Rietveld refinement. The powders were pure single pervoskite phase with high crystallinity. FESEM and TEM were used to determine particle size and morphology. The average LiTaO3 grain size was estimated to be < 200nm, and TEM images indicated that LiTaO3 particles had a brick-like morphology. In addition, the effect of the temperature on the LiTaO3 power characterisitics was also detailed studied.

Microstructural Characterization of a Fe-Based Compostie Reinforced by TiC

2011 ◽  
Vol 675-677 ◽  
pp. 835-838
Author(s):  
Jing Wang ◽  
Si Jing Fu ◽  
Hong Cheng
Keyword(s):  
Electron Microscope ◽  
Microstructural Characterization ◽  
Interfacial Structure ◽  
Synthesis Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Tic Particle ◽  
Scanning Electron

The present work reported the preparation of TiC/Fe-based composite by the synthesis reaction from Ti, C and Fe. The sintered composites were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope. TiC, Fe3C and α-Fe were detected by X-ray diffraction analysis. The scanning and transmission electron micrographs revealed the morphology and distribution of the reinforcements, the microstructure of Fe matrix, the interfacial structure of TiC particle-to-Fe matrix. Moreover, the formation reason of the voids in composite was also discussed.

Ultrafast Response Humidity Sensor Based on Electrospun Porous BaTiO3 Nanofibers

2013 ◽  
Vol 319 ◽  
pp. 43-48 ◽  
Author(s):  
Hong Di Zhang ◽  
Chen Hao Sheng ◽  
Bin Sun ◽  
Yun Ze Long
Keyword(s):  
Electron Microscope ◽  
Recovery Time ◽  
Room Temperature ◽  
Humidity Sensor ◽  
Humidity Sensing ◽  
X Ray ◽  
Transmission Electron ◽  
Porous Microstructure ◽  
Humidity Sensing Properties ◽  
Scanning Electron

Nanocrystalline and porous barium titanate (BaTiO3) nanofibers with diameter 200-400 nm were synthesized via electrospinning and followed calcinations. The morphology and microstructure of the nanofibers were characterized using field emission scanning electron microscope, X-ray diffractometer and transmission electron microscope, respectively. And the electrical and humidity sensing properties of the nanofibers were also measured. The results reveal that the BaTiO3 nanofibers have a conductivity of about 0.3 S/cm, and show an ultrafast response time (~0.7 s) and a recovery time (~0.4 s) to humidity at room temperature. In addition, the sensing mechanism was also discussed briefly based on its nanocrystalline and porous microstructure of the electrospun material.

Synthesis and Characterization of Lamellar Nanostructured Yttrium Films Using Lyotropic Liquid Crystalline Templates

2011 ◽  
Vol 399-401 ◽  
pp. 1915-1918
Author(s):  
Rui Jie Guo ◽  
Xiao Juan Sha ◽  
Lei Lei Cao
Keyword(s):  
Electron Microscope ◽  
Liquid Crystalline ◽  
Electroless Deposition ◽  
Electronic Materials ◽  
X Ray Diffraction ◽  
Regular Array ◽  
X Ray ◽  
Surface Areas ◽  
Transmission Electron

The lamellar nanostructured yttrium films on α-Al2O3 substrates were successfully synthesized by electroless deposition using the lyotropic liquid crystalline templating strategy. The reaction of hydrazine hydrate and Y3+ dissolved within the aqueous domains of the lyotropic liquid crystalline phase produced the nanostructured yttrium films. The low-angle X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) indicated that the as-resulted films possessed lamellar regular array of nanochannels with periodicity of 6 nm. With well-defined nanochannels and higher surface areas, the nanostructured films may find applications in the field of electronic materials.

MAGNETIC CHARACTERIZATION OF WEB-LIKE CARBON NANOTUBES CATALYZED BY Fe2O3 VIA PULSED LASER ABLATION DEPOSITION (PLAD) TECHNIQUE

2011 ◽  
Vol 10 (03) ◽  
pp. 403-412 ◽  
Author(s):  
ISMAYADI ISMAIL ◽  
MANSOR HASHIM ◽  
NOORHANA YAHYA
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Laser Ablation ◽  
Glass Substrate ◽  
Vibrating Sample Magnetometer ◽  
Graphite Target ◽  
X Ray ◽  
Transmission Electron ◽  
532 Nm

Web-like carbon nanotubes were synthesized via Laser Ablation Deposition (PLAD) in a T-shape stainless steel chamber. An Nd -YAG laser with a 532 nm wavelength was used to irradiate a target of graphite and a catalyst, with a 5–7 ns pulsed width. Fe2O3 was used as a catalyst to produce a reactive graphite target. The vacuum level was kept at 5 Torr with argon gas flowing from the bottom of the chamber. The plume that was deposited on a glass substrate was then characterized using a Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) analysis, a Transmission Electron Microscope (TEM), and a Vibrating Sample Magnetometer (VSM). Web-like CNT structures were deposited on the glass substrate. These web-like structures were randomly aligned with sizes of 99 nm to 234 nm. TEM images confirmed that these web-like structures were CNTs. VSM results showed that the encapsulation of the Fe2O3 catalyst had influenced the magnetic properties of the CNTs. The magnetic property of CNTs was increased with the increasing amount of the Fe2O3 catalyst filling the CNTs. We assert that the starting catalyst material was transformed from hematite to magnetite via maghemite by a structural change under a reduced oxygen atmosphere during the laser ablation.

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