scholarly journals MOCVD Growth of GeTe/Sb2Te3 Core–Shell Nanowires

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 718
Author(s):  
Arun Kumar ◽  
Raimondo Cecchini ◽  
Claudia Wiemer ◽  
Valentina Mussi ◽  
Sara De Simone ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Average Length ◽  
Chemical Vapour ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Electron Energy Loss

We report the self-assembly of core–shell GeTe/Sb2Te3 nanowires (NWs) on Si (100), and SiO2/Si substrates by metalorganic chemical vapour deposition, coupled to the vapour–liquid–solid mechanism, catalyzed by Au nanoparticles. Scanning electron microscopy, X-ray diffraction, micro-Raman mapping, high-resolution transmission electron microscopy, and electron energy loss spectroscopy were employed to investigate the morphology, structure, and composition of the obtained core and core–shell NWs. A single crystalline GeTe core and a polycrystalline Sb2Te3 shell formed the NWs, having core and core–shell diameters in the range of 50–130 nm and an average length up to 7 µm.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

Characterisation of Chemical Vapour Deposited AlHfN Coatings

2020 ◽  
Vol 405 ◽  
pp. 33-39
Author(s):  
Elisabeth Rauchenwald ◽  
Mario Lessiak ◽  
Ronald Weissenbacher ◽  
Sabine Schwarz ◽  
Roland Haubner
Keyword(s):  
Electron Microscopy ◽  
Protective Coatings ◽  
Cutting Tools ◽  
Chemical Vapour ◽  
Gas Composition ◽  
X Ray Diffraction ◽  
Multilayer Systems ◽  
X Ray ◽  
Transmission Electron ◽  
Hcl Gas

Chemical vapour deposited HfN can be utilised as a component of multilayer systems in protective coatings on cutting tools. In this study, related AlHfN coatings were synthesized through a reaction of metallic hafnium and aluminium with HCl gas forming gaseous HfCl4 and AlCl3, which were subsequently transported into a heated coating reactor. Via high temperatures and separately introduced NH3 and N2 as reaction gases, AlHfN coatings were deposited on hardmetal inserts. By varying the ratio between AlCl3 and HfCl4, compositionally different AlHfN coatings were examined. Additionally, surface morphology, composition as well as crystalline phases of the obtained coatings were analysed by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Finally, the microstructure of the cross section of a coating was investigated via transmission electron microscopy. The observations revealed a great impact of the gas composition on the morphology and crystal structures of the coatings. Within the layer, the growth of columnar microstructures was detected. Additionally, the formation of an amorphous HfN intermediate layer between the substrate and the AlHfN with a thickness of approximately 2 nm was found.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

SURFACE BONDING STATES OF NANO-CRYSTALLINE DIAMOND BALLS

2001 ◽  
Vol 15 (31) ◽  
pp. 4071-4085 ◽  
Author(s):  
J. L. PENG ◽  
SHAUN BULCOCK ◽  
PETER I. BELOBROV ◽  
L. A. BURSILL
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapour ◽  
Structural Models ◽  
Electronic States ◽  
Surface Structures ◽  
Atomic Scale ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Electron Energy Loss

The rough surface of nano-crystalline diamond spheres induces surface electronic states which appear as a broadened pre-peak over approx. 15 eV at the C K-edge energy threshold for carbon in the parallel electron energy loss spectrum (PEELS). This appears to be at least partially due to 1s-π* transitions, although typically the latter occupy a range of only 4 eV for the sp2 edge of highly-oriented pyrollytic graphite (HOPG). No π* electrons appear in the conduction band inside the diamond particles, where all electrons are sp3 hybridized. PEELS data were also obtained from a chemical vapour deposited diamond film (CVDF) and gem-quality diamond for comparison with the spectra of nano-diamonds. The density of sp2 and sp3 states on the surface of diamond nano-crystals is calculated for simple structural models of the diamond balls, including some conjecture about surface structures. The results are used to interpret the sp2/sp3 ratios measured from the PEELS spectra recorded as scans across the particles. Surface roughness at the atomic scale was also examined using high-resolution transmission electron microscopy (HRTEM) and electron nano-diffraction patterns were used to confirm the crystal structures.

Preparation, Characterization and Application in Electromagnetic Wave Absorption of Core-Shell C/Fe3O4 Nanocomposites

2011 ◽  
Vol 239-242 ◽  
pp. 1725-1730 ◽  
Author(s):  
Qiang Chun Liu ◽  
Jian Ming Dai ◽  
Zhen Fa Zi ◽  
Da Jun Wu ◽  
Yu Ping Sun
Keyword(s):  
Electron Microscopy ◽  
Solution Method ◽  
Wide Frequency Range ◽  
Core Shell ◽  
Carbon Sphere ◽  
Carbon Spheres ◽  
X Ray Diffraction ◽  
Microwave Absorption Properties ◽  
Transmission Electron ◽  
Better Than

Large-quantity core-shell carbon spheres/Fe3O4nanocomposites were synthesized via a simple solution method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the carbon spheres were covered by a layer of Fe3O4nanoparticles with a diameter of about 25 nm. Measurements of the electromagnetic parameters of the samples showed that microwave absorption properties of the carbon sphere-Fe3O4nanocomposites were much better than that of the pure Fe3O4or the mixtures of carbon spheres and Fe3O4microspheres. The optimal reflection loss (RL) reached −37.8 dB at 14.8 GHz for a layer thickness of 2.0 mm, which is favorable for application of our samples in a wide frequency range.

Fabrication of boron carbonitride (BCN) nanotubes and giant fullerene cages

2010 ◽  
Vol 88 (12) ◽  
pp. 1256-1261 ◽  
Author(s):  
Guifang Sun ◽  
Faming Gao ◽  
Li Hou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
The Novel ◽  
X Ray Diffraction ◽  
Boron Carbonitride ◽  
X Ray ◽  
Transmission Electron ◽  
New Form ◽  
First Time ◽  
Electron Energy Loss

Boron carbonitride (BCN) nanotubes have been successfully prepared using NH4Cl, KBH4, and ZnBr2 as the reactants at 480 °C for 12 h by a new benzene-thermal approach in a N2 atmosphere. As its by-product, a new form of carbon regular hexagonal nanocages are observed. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), transmission electron diffraction (TED), electron energy loss spectroscopy (EELS), and high-resolution transmission electron microscopy (HRTEM). The prepared nanotubes have uniform outer diameters in the range of 150 to 500 nm and a length of up to several micrometerss. The novel carbon hexagonal nanocages have a typical size ranging from 100 nm to 1.5 µm, which could be the giant fullerene cages of [Formula: see text] (N = 17∼148). So, high fullerenes are observed for the first time. The influences of reaction temperature and ZnBr2 on products and the formation mechanism of BCN nanotubes are discussed.

Self-Assembly of Gold Nanoparticles on Gold Core-Induced Polypyrrole Nanohybrids for Electrochemical Sensor of Dopamine

NANO ◽  
2015 ◽  
Vol 10 (08) ◽  
pp. 1550115 ◽  
Author(s):  
Junwei Ding ◽  
Kai Zhang ◽  
Wei Xu ◽  
Zhiqiang Su
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Self Assembly ◽  
Chemical Oxidation ◽  
X Ray Diffraction ◽  
Detection Range ◽  
In Situ Chemical Oxidation ◽  
Gold Core ◽  
Transmission Electron ◽  
Chemical Oxidation Polymerization

Gold core-induced polypyrrole nanohybrids (Au–PPyNHs) were successfully synthesized via in situ chemical oxidation polymerization of pyrrole molecules, and their structure was directly confirmed and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Furthermore, gold nanoparticles (AuNPs) were assembled onto the as-prepared Au–PPyNHs by electrostatic interaction to fabricate the nanohybrids of Au–PPyNH–Au. The created Au–PPyNH–Au nanohybrids was immobilized onto glassy carbon electrode and applied to construct dopamine (DA) sensor. We found that the fabricated sensor with Au–PPyNH–Au nanohybrids is highly specific probe for sensing DA. The Au–PPyNH–Au based DA sensor has a linear detection range from 1[Formula: see text][Formula: see text]M to 0.321 mM and a detection limit of 0.32[Formula: see text][Formula: see text]M.

Air-Water Interfacial Film of Zirconia and its Heat-Treatment

2011 ◽  
Vol 295-297 ◽  
pp. 1095-1098
Author(s):  
Chun Kan
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Self Assembly ◽  
Energy Dispersive Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconia Film ◽  
Transmission Electron ◽  
Assembly Structure ◽  
Calcined Temperature

The air-water interfacial zirconia film composed of nanodisks with self-assembly structure is prepared. Scanning electron microscopy (SEM), Energy Dispersive Spectrum (EDS), X-ray diffraction (XRD) and Transmission electron microscopy (TEM) are used to characterize the film. Furthermore, the heat-treatment of this film is studied by thermogravimetry and differential thermal analysis (TG-DTA), XRD, and Raman spectroscopy (Raman). The results suggest that the zirconia of the samples changes from amorphous phase to t-ZrO2phase then m-ZrO2phase with the rise of calcined temperature.

Enhancement of durability of NIR emission of Ag2S@ZnS QDs in water

2017 ◽  
Vol 31 (32) ◽  
pp. 1750297 ◽  
Author(s):  
M. Karimipour ◽  
M. Bagheri ◽  
M. Molaei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Xrd Analysis ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nir Emission ◽  
Core Shell Structure ◽  
Phase Transmission

Stability of Ag2S@ZnS QDs in water is a crucial concern for their application in biology. In this work, both physical sustainability and emission stability of Ag2S QDs were enhanced using parameter optimization of a pulsed microwave irradiation (MI) method up to 105 days after their preparation. UV–Vis and photoluminescence spectroscopies depicted an absorption and emission about 817 nm and 878 nm, respectively. X-ray diffraction (XRD) analysis showed a growth of Ag2S acanthite phase. Transmission Electron Microscopy (TEM) images revealed a clear formation of Ag2S@ZnS core–shell structure.

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