Effect of oxygen vacancies on the surface morphology and structural properties of WO3– x nanoparticles

2019 ◽  
Vol 9 (7) ◽  
pp. 773-777 ◽  
Author(s):  
Zhiguang Yang ◽  
Chaosheng Zhu ◽  
Zhiqiang Hou ◽  
Peng Peng
Keyword(s):  
Electron Microscopy ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Diffraction Field ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Effect Of Oxygen

WO3 is an essential material for energy storage and catalytical technology, the oxygen vacancies level will play an essential role in its potential application. In this paper, porous tungsten oxide (WO3–x) with various oxygen contents was quickly fabricated by a microwave plasma-enhanced chemical vapor deposition method. A detailed characterization of structure and morphology features with the plasma handling process was recorded by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy, respectively. The etching mechanism of porous WO3–x under H2 plasma was discussed based on the systemically characterization. These results will help us to design the active sites or structure in the metal oxide materials.

scholarly journals Fabrication and Physical Properties of Single-Crystalline Βeta-FeSi2 Nanowires

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Chih-Yung Yang ◽  
Shu-Meng Yang ◽  
Yu-Yang Chen ◽  
Kuo-Chang Lu
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Field Emitters ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Carrier Gases

Abstract In this study, self-catalyzed β-FeSi2 nanowires, having been wanted but seldom achieved in a furnace, were synthesized via chemical vapor deposition method where the fabrication of β-FeSi2 nanowires occurred on Si (100) substrates through the decomposition of the single-source precursor of anhydrous FeCl3 powders at 750–950 °C. We carefully varied temperatures, duration time, and the flow rates of carrier gases to control and investigate the growth of the nanowires. The morphology of the β-FeSi2 nanowires was observed with scanning electron microscopy (SEM), while the structure of them was analyzed with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The growth mechanism has been proposed and the physical properties of the iron disilicide nanowires were measured as well. In terms of the magnetization of β-FeSi2, nanowires were found to be different from bulk and thin film; additionally, longer β-FeSi2 nanowires possessed better magnetic properties, showing the room-temperature ferromagnetic behavior. Field emission measurements demonstrate that β-FeSi2 nanowires can be applied in field emitters.

Control of Morphology and Growth Direction of Gallium Nitride Nanostructures

2003 ◽  
Vol 789 ◽  
Author(s):  
Seung Yong Bae ◽  
Hee Won Seo ◽  
Jeunghee Park
Keyword(s):  
Electron Microscopy ◽  
Gallium Nitride ◽  
Large Scale ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Oxide Mixture ◽  
Temperature Range ◽  
Transmission Electron

ABSTRACTVarious shaped single-crystalline gallium nitride (GaN) nanostructures were produced by chemical vapor deposition method in the temperature range of 900–1200 °C. Scanning electron microscopy, transmission electron microscopy, electron diffraction, x-ray diffraction, electron energy loss spectroscopy, Raman spectroscopy, and photoluminescence were used to investigate the structural and optical properties of the GaN nanostructures. We controlled the GaN nanostructures by the catalyst and temperature. The cylindrical and triangular shaped nanowires were synthesized using iron and gold nanoparticles as catalysts, respectively, in the temperature range of 900 – 1000 °C. We synthesized the nanobelts, nanosaws, and porous nanowires using gallium source/ boron oxide mixture. When the temperature of source was 1100 °C, the nanobelts having a triangle tip were grown. At the temperature higher up to 1200 °C the nanosaws and porous nanowires were formed with a large scale. The cylindrical nanowires have random growth direction, while the triangular nanowires have uniform growth direction [010]. The growth direction of the nanobelts is perpendicular to the [010]. Interestingly, the nanosaws and porous nanowires exhibit the same growth direction [011]. The shift of Raman, XRD, and PL bands from those of bulk was correlated with the strains of the GaN nanostructures.

Synthesis of MoS2 Nanoparticles with Inorganic Fullerene-Like Structure from Molybdenum Trioxide and Sulfur

2012 ◽  
Vol 554-556 ◽  
pp. 601-604
Author(s):  
Bin Gao ◽  
Xiao Jun Zhang
Keyword(s):  
Electron Microscopy ◽  
Molybdenum Trioxide ◽  
Raw Materials ◽  
Heating Temperature ◽  
Chemical Vapor ◽  
Diffraction Field ◽  
Chemical Vapor Deposition Method ◽  
X Ray ◽  
Inorganic Fullerene ◽  
Transmission Electron

MoS2 nanoparticles with fullerene-like (IF-MoS2) structure were successfully obtained at heating temperature higher than 840 °C by chemical vapor deposition method in a three-tube furnace using MoO3 and S (sulfur) powders as raw materials. The synthesized samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and energy dispersion X-ray spectrometerrespectively. IF-MoS2 nanoparticles can be obtained only in the narrow temperature range of 840 °C-870 °C, and the diameter of IF-MoS2 nanoparticles increases with temperature. A gradual formation mechanism of IF-MoS2 nanoparticles was discussed in detail.

Growth and Photoluminescence of β-SiC Nanowires on Porous Silicon Array

2013 ◽  
Vol 662 ◽  
pp. 11-15
Author(s):  
Hai Yan Wang ◽  
Li Ping Kang ◽  
Yong Qiang Wang ◽  
Zi Jiong Li
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Fluorescent Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Nanowires ◽  
Quantum Confinement Effects ◽  
Transmission Electron

Nonaligned and curly β-SiC nanowires (nw-SiC) were grown on porous silicon array (PSA) by a chemical vapor deposition method with nickel as the catalyst. The morphology, structure and the composition of the nw-SiC/PSA and the SiC-SiO2core-shell fibers which is the semi-product were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Based on the experimental results a possible growth mechanism of nw-SiC was explained. Two broad photoluminescence peaks located around ~409 and ~494 nm were observed in nw-SiC/PSA in the PL measurement when utilizing 300 nm ultraviolet fluorescent light excited at room temperature. The excellent luminescent performances are ascribed to the quantum confinement effects in nw-SiC. The optical merits of nw-SiC/PSA made it a promising material in the fields of ultraviolet-blue emitting devices.

scholarly journals Synthesis and Optical Properties of CdSxSe1-x Semiconductor Nanomaterials by Chemical Vapor Deposition Method

2019 ◽  
Vol 12 (3) ◽  
pp. 55-64
Author(s):  
Nadia M. Jassim
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Vls Growth

Highly pure and crystalline CdSxSe1 -x nanostructures have been successfully synthesized via Chemical Vapor Deposition (CVD) method, changing the components of x, in order to adjust the band gap of materials, and the relationship with the lattice constant. Using X-ray Diffraction (XRD) to characterize the phase structures and elemental compositions of the samples, and using Field Emission Scanning Electron Microscopy (FESEM) to observe the surface morphology of CdSxSe1 -x nanomaterials and confirm the VLS growth mechanism. Using the High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED) to analyze the crystal structure and the growth direction of the materials

Highly oriented diamond growth on positively biased Si substrates

2001 ◽  
Vol 16 (12) ◽  
pp. 3351-3354 ◽  
Author(s):  
Te-Fu Chang ◽  
Li Chang
Keyword(s):  
Electron Microscopy ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Plasma Chemical Vapor Deposition ◽  
Si Substrates ◽  
Transmission Electron

Deposition of highly textured diamond films on Si(001) has been achieved by using positively bias-enhanced nucleation in microwave plasma chemical vapor deposition. During the biasing period, an additional glow discharge due to the dc plasma effect appeared between the electrode and the substrate. The discharge is necessary for enhanced nucleation of diamond. X-ray diffraction, scanning electron microscopy, and cross-sectional transmission electron microscopy (XTEM) were used to characterize the microstructure of the diamond films on Si. The results show the morphology of diamond grains in square shape with strong diamond (001) texture. XTEM reveals that an amorphous interlayer formed on the smooth Si surface before diamond nucleation.

scholarly journals Effects of Precursor-Substrate Distances on the Growth of GaN Nanowires

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Hongbin Cheng ◽  
Jia Li ◽  
Dongxu Wu ◽  
Yanxi Li ◽  
Zhiguang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalyst Activity ◽  
Chemical Vapor ◽  
Photoluminescence Property ◽  
Diffraction Field ◽  
Uniform Density ◽  
X Ray Diffraction ◽  
Gan Nanowires ◽  
Transmission Electron ◽  
Gan Nanowire

GaN nanowires were synthesized through the Ni-catalyzed chemical vapor deposition (CVD) method using Ga2O3/GaN mixtures as gallium sources, and precursor-substrate distances were investigated as the important factor for the growth of GaN nanowires. The microstructure, composition, and photoluminescence property were characterized by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectra. The results showed that single crystalline GaN nanowires with the diameter of about 90 nm and the length up to tens of micrometers had been grown thickly across Si (100) substrates with uniform density. Moreover, the variations of the GaN nanowire morphology, density, and size were largely attributed to substrate positions which would influence Ga precursor density in the carrier gas, the saturation degree of gaseous reactants, and the catalyst activity, respectively, in the fabrication of GaN nanowires by the vapour liquid solid mechanism.

Low Temperature Large Scale CVD Synthesis of Nano Onion-Like Fullerenes

2012 ◽  
Vol 490-495 ◽  
pp. 3211-3214 ◽  
Author(s):  
Lei Shan Chen ◽  
Cun Jing Wang
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Aluminum Hydroxide ◽  
Large Scale ◽  
Iron Catalyst ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Naoh Solution ◽  
Synthesis Reactions

Synthesis reactions were carried out by chemical vapor deposition using iron catalyst supported on aluminum hydroxide at 400 °C and 420 °C, in the presence of argon as carrier gas and acetylene as carbon source. The aluminum hydroxide support was separated by refluxing the samples in 40% NaOH solution for 2 h and 36% HCl solution for 24 h, respectively. The samples were characterized by field-emission scanning electron microscopy, energy dispersive spectroscopy, high-resolution transmission electron microscopy and X-ray diffraction. The results show that carbon nanotubes were the main products at 420 °C, while large scale high purity nano onion-like fullerenes encapsulating Fe3C, with almost uniform sizes ranging from 10-50 nm, were obtained at the low temperature of 400 °C.

Understanding the Growth Mechanisms of Tin Oxide Nanowires by Chemical Vapor Deposition

2021 ◽  
Vol 21 (4) ◽  
pp. 2538-2544
Author(s):  
Nguyen Minh Hieu ◽  
Nguyen Hoang Hai ◽  
Mai Anh Tuan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Mapping ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Transmission Electron ◽  
Scanning Transmission

Tin oxides nanowires were prepared by chemical vapor deposition using shadow mask. X-ray diffraction indicated that the products were tetragonal having crystalline structure with lattice constants a = 0.474 nm and c = 0.318 nm. The high-resolution transmission electron microscopy revealed that inter planar spacing is 0.25 nm. The results chemical mapping in scanning transmission electron microscopy so that the two elements of Oxygen and Tin are distributed very homogeneously in nanowires and exhibit no apparent elements separation. A bottom-up mechanism for SnO2 growth process has been proposed to explain the morphology of SnO2 nanowires.

Fe-encapsulating carbon nano onionlike fullerenes from heavy oil residue

2008 ◽  
Vol 23 (5) ◽  
pp. 1393-1397 ◽  
Author(s):  
Yongzhen Yang ◽  
Xuguang Liu ◽  
Bingshe Xu
Keyword(s):  
Electron Microscopy ◽  
Heavy Oil ◽  
Chemical Vapor ◽  
Catalyst Precursor ◽  
X Ray Diffraction ◽  
Self Assembling ◽  
Transmission Electron ◽  
Oil Residue ◽  
Heavy Oil Residue ◽  
Graphite Sheets

Fe-encapsulating carbon nano onionlike fullerenes (NOLFs) were obtained by chemical vapor deposition (CVD) using heavy oil residue as carbon source and ferrocene as catalyst precursor in an argon flow of 150 mL/min at 900 °C for 30 min. Field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD), and Raman spectroscopy were used to characterize morphology and microstructure of the products. The results show that Fe-encapsulating NOLFs collected at the outlet zone of quartz tube had core/shell structures with sizes ranging from 3 to 6 nm and outer shells composed of poorly crystallized graphitic layers. Their growth followed particle self-assembling growth mechanism, and all atoms in the graphite sheets primarily arose from Fe-carbide nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document