scholarly journals Structural Properties of Zn-ZnO Core-Shell Microspheres Grown by Hot-Filament CVD Technique

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
R. López ◽  
T. Díaz ◽  
G. García ◽  
R. Galeazzi ◽  
E. Rosendo ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Raw Material ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hot Filament Cvd ◽  
Phase Nucleation ◽  
The One ◽  
Xrd Techniques ◽  
Hot Filament

We report the hot-filament chemical vapor deposition (HFCVD) growth of Zn-ZnO core-shell microspheres in the temperature range of 350–650°C only using ZnO pellets as raw material. The samples were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques. SEM micrographs showed the presence of solid microspheres and a Zn-ZnO layer in all samples. The observed heterogeneous morphology on each sample suggested two different growth mechanisms. On the one hand, solid microspheres were formed by means of gas phase nucleation of Zn atoms. The Zn-ZnO layer was formed on the substrate as result of surface reactions. It is possible that Zn microspheres condensed during the natural cooling of the HFCVD reactor as they were observed on the Zn-ZnO layer.

Synthesis of Crystalline C3N4 films and the new C-N Phases

1996 ◽  
Vol 441 ◽  
Author(s):  
Yan Chen ◽  
D. J. Johnson ◽  
R. H. Prince ◽  
Liping Guo ◽  
E. G. Wang
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Growth Parameters ◽  
Chemical Vapor ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Transmission Electron ◽  
Hot Filament

AbstractCrystalline C-N films composed of α- and β-C3N4, as well as other C-N phases, have been synthesized via bias-assisted hot-filament chemical vapor deposition using a gas mixture of nitrogen and methane. Scanning electron microscopy(SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the films. Lattice constants of the α- and β-C3N4 phases obtained coincide very well with the theoretical values. In addition to these phases, two new C-N phases in the films have been identified by TEM and XRD; one having a tetragonal structure with a = 5.65 Å, c = 2.75Å, and the second having a monoclinic structure with a = 5.065 Å, b= 11.5 Å, c = 2.801 Å and β = 96°. Their stoichiometric values and atomic arrangements have not yet been identified. Furthermore, variation in growth parameters, for example methane concentration, bias voltage, etc., can yield preferred growth of different C-N phases.

Application of a Thermobalance for studying Deposition kinetics of Diamond Films

1989 ◽  
Vol 162 ◽  
Author(s):  
Jerry Czarnecki ◽  
David Thumim
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Carbon Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Deposition Kinetics ◽  
Oxidation Rates ◽  
Exponential Increase ◽  
Hot Filament ◽  
Kinetics Of

ABSTRACTWeight recording using a thermobalance type Cahn TG-171 has been applied to study Hot, Filament Enhanced Chemical Vapor Deposition (HFCVD) of carbon films from methane. Changes in the deposition rates during each individual process may indicate four stages of the deposition kinetics: 1- generation of nuclei (slow, linear); 2- growth on nuclei (exponential increase); 3- aggregation of crystals (slowing); 4- growth on the surface of diamond film, completely covering the substrate (linear). An attempt to determine the concentration of graphite in the deposited layer, based on differences in oxidation rates of diamond and graphite has been proposed, as supplementary to X-ray diffraction and Raman spectroscopy.

Growth and characterization of type II ZnO/ZnSe core/shell nanowire arrays

2010 ◽  
Vol 25 (7) ◽  
pp. 1272-1277 ◽  
Author(s):  
Jinjian Zheng ◽  
Zhiming Wu ◽  
Weihuang Yang ◽  
Shuping Li ◽  
Junyong Kang
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor ◽  
Band Alignment ◽  
Nanowire Arrays ◽  
Core Shell ◽  
Type Ii ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications

Type II ZnO/ZnSe core/shell nanowire arrays were grown by a two-step chemical vapor deposition. The nanowire arrays with dense nanoislands on the surface are well aligned and normal to the substrate imaged by scanning electron microscopy. The core/shell structure of nanowires was identified by a high-resolution transmission electron microscopy. The structure and composition of the shell were confirmed to be wurtzite ZnSe by x-ray diffraction, Raman scattering and energy-dispersive x-ray spectroscopy. Moreover, an intense emission was observed at 1.89 eV smaller than the band gaps of core and shell materials by photoluminescence, indicating the achievement of the type II band alignment at the interface. This study is expected to contribute to the potential applications in novel photovoltaic devices.

Fabrication and Applications of Ultra-Smooth Composite Diamond Coated WC-Co Drawing Dies

2011 ◽  
Vol 175 ◽  
pp. 233-238 ◽  
Author(s):  
Bin Shen ◽  
Fang Hong Sun ◽  
Zhi Ming Zhang ◽  
He Sheng Shen ◽  
Song Shou Guo
Keyword(s):  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Entry Zone ◽  
X Ray ◽  
Nano Crystalline ◽  
Composite Diamond ◽  
And Performance ◽  
Hot Filament ◽  
Drawing Dies

Micro/nano-crystalline multilayered ultra-smooth diamond (USCD) films are deposited on the interior-hole surface of conventional WC-Co drawing dies with a combined process consisting of the hot filament chemical vapor deposition (HFCVD) method and polishing technique. Scanning electron microscopy (SEM), surface profilemeter, Raman spectroscopy and X-ray diffraction (XRD) are employed to provide a characterization of as-deposited USCD films. The results exhibit that as-deposited USCD films present an ultra-smooth surface, its surface roughness values (Ra) in the entry zone, drawing zone and bearing zone are measured as 25.7 nm, 23.3 nm and 25.5 nm respectively. Furthermore, the working lifetime and performance of as-fabricated USCD coated drawing dies are examined in producing copper tubes with hollow sinking, fixed plug and floating plug. The results show that the lifetime of USCD coated drawing is as more than 30 times as that of WC-Co drawing dies in the drawing process with hollow sinking, 7 times in the fixed plug drawing and 10 times in the floating drawing.

Characterization of Nitrogen Doped Diamond Electrodes Produced by Hot Filament Chemical Vapor Deposition

2014 ◽  
Vol 802 ◽  
pp. 180-185 ◽  
Author(s):  
Nazir M. Santos ◽  
Tatiane M. Arantes ◽  
Neidênei G. Ferreira ◽  
Mauricio R. Baldan
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Nitrogen Doping ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Diamond Electrodes ◽  
X Ray ◽  
Nitrogen Doped ◽  
Hot Filament

The purpose of this work is to study the structural and morphological modification of the surface of the n-type diamond electrodes as a function of nitrogen doping. The characterizations of these electrodes were made using Raman Spectroscopy, Contact Angle, X-ray diffraction and Scanning Electron Microscopy (SEM). The nitrogen-doped diamond (NDD) electrodes were produced using Hot Filament-assisted Chemical Vapor Deposition method (HFCVD) from methane, hydrogen and nitrogen in the gas mixture. The results from Raman spectroscopy show that the diamond films obtained with nitrogen addition presented one large band at 1100-1700 cm-1. The SEM images showed that the variation in the nitrogen doping influenced the growth rate of films by promoting changes in the sizes of grains from microcrystalline to nanocrystalline texture. This behavior supported the results obtained from X-ray diffraction analyses. It was possible to verify a decrease in the crystallite size as a function of the nitrogen increase.

scholarly journals Photoluminescent Enhancement by Effect of Incorporation Nickel in ZnO Films Grown

2021 ◽  
Vol 6 (5) ◽  
pp. 177-180
Author(s):  
Delfino R. Gutiérrez ◽  
Tomás Díaz-Becerril ◽  
Godofredo García-Salgado ◽  
Antonio Coyopol-Solís ◽  
Enrique Rosendo-Andrés ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Surface Defects ◽  
Chemical Vapor ◽  
Green Emission ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Green Emission Band ◽  
The Right ◽  
Hot Filament

Microstructured films of undoped zinc oxide (ZnO) and ZnO doped with nickel (ZnO:Ni) were grown by hot filament chemical vapor deposition (HFCVD) technique on Si (100) substrates at 500 °C. Pellets of ZnO and ZnO:NiO as oxidant agenst were used. A shift to the right around 0.17 degree of the X-Ray Diffraction pattern of the ZnO:Ni film was observed with respect to undoped ZnO films. Morphologically by Scanning Electron Microscopy was noticed a Core-Shell type growth in ZnO undoped and a nanostructured type (Nano-wire) in ZnO doped with Ni. Photoluminescence measurements showed an increase in the intensity of the green emission band of ZnO:Ni. It was attributed to defects of oxygen vacancies (VO), zinc vacancies (VZn), zinc interstitials (Zni), oxygen interstitials (Oi), and oxygen vacancies complex (VO complex) in the structure of the film. The incorporation of Ni atoms in the ZnO structure stresses the crystal lattice, leaving behind a large number of surface defects that increase the emission of PL.

Time-Temperature Effect for Preparation of SnO2 Nanostructures Using Carbon Assisted

2014 ◽  
Vol 680 ◽  
pp. 38-41
Author(s):  
Dheerachai Polsongkram ◽  
Pattanasuk Chamninok ◽  
Suchaowadee Changsakul ◽  
Atipong Sriputhorn ◽  
Supakorn Pukird
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Xrd Techniques ◽  
Source Materials ◽  
Vapor Deposit ◽  
Scanning Electron

We studied the effect of time and temperature for preparation of SnO2 nanostructures by chemical vapor deposit methods. SnO2 nanostructures were synthesized using Sn powder with carbon charcoal as starting materials. The source materials and Si substrates were heated with various times, temperatures under atmosphere of nitrogen and oxygen. The synthesized products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) techniques. The results showed the nanostructures of prepared products were very uniformly of SnO2 nanowires with diameter about 100-300 nm and length around more 1-2 μm depending on times and temperatures.

SYNTHESIS OF HIGH QUALITY CRYSTALLINE C-N FILMS ON SILICON

1996 ◽  
Vol 10 (12) ◽  
pp. 567-571 ◽  
Author(s):  
YAN CHEN ◽  
E.G. WANG ◽  
FENG CHEN ◽  
LIPING GUO
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Interfacial Layer ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Hot Filament ◽  
Microscopy Images

High quality crystalline C–N films have been synthesized via hot filament chemical vapor deposition using a gas mixture of nitrogen and methane. Scanning electron microscopy images show that a high density of crystalline clusters has been achieved. The clusters are composed of small columnar crystals (20–200 nm across) with hexagonal facets. Energy dispersive X ray analysis indicates a relative nitrogen:carbon composition of 1.30–2.5. X ray diffraction results indicate the films composed of β- and α- C 3 N 4 phases. Together with transmission electron microscopy analyses, we suggest that an interfacial layer C 3−x Si x N 4 is formed between the silicon substrate and the crystalline carbonnitride films.

scholarly journals Fast Formation of Surface Oxidized Zn Nanorods and Urchin-Like Microclusters

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
R. López ◽  
T. Díaz ◽  
G. García ◽  
E. Rosendo ◽  
R. Galeazzi ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Zno Nanorods ◽  
Chemical Vapor ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Vapor Deposition Technique ◽  
Vapor Deposition Technique ◽  
Hot Filament

Entangled Zn-ZnO nanorods and urchin-like microstructures were synthesized by the hot filament chemical vapor deposition technique at 825 and 1015°C, respectively. X-ray diffraction results showed a mixture of ZnO and Zn phases in both nanorods and urchin-like structures. The presence of Zn confirms the chemical dissociation of the ZnO solid source. The Z-ZnO nanorods with diameter of about 100 nm showed dispersed-like morphology. The urchin-like structures with micrometer diameters exhibited porous and rough morphology with epitaxial formation of nanorods.

scholarly journals Assessment of the quality of calcination of marbles from Thassos Island using Raman spectroscopy and X-Ray Diffraction

2013 ◽  
Vol 47 (4) ◽  
pp. 2040 ◽  
Author(s):  
G. Leontakianakos ◽  
I. Baziotis ◽  
E. Profitis ◽  
E. Chatzitheodoridis ◽  
S. Tsimas
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Reactivity ◽  
Transformation Process ◽  
Raw Material ◽  
Solution Temperature ◽  
X Ray Diffraction ◽  
Quick Lime ◽  
X Ray ◽  
Slaked Lime ◽  
Xrd Techniques

The degree of calcination of a dolomitic and a calcitic marble from Thassos Island, was investigated, by combining both Raman spectroscopy (RS) and X-Ray diffraction (XRD) techniques. The samples were prepared in isometric 2 cm cubes and calcined at three different temperatures, 900, 1050 and 1200 0C for 2 hours in order to produce quick lime. RS was applied at the lime sample’s surface and inner (near core) part after gently crushing. XRD was applied on the bulk rock specimens in order to verify the transformation process during heating of the raw material. Quality control of the applied calcination procedure is provided through the hydration of quick lime. The rise in solution temperature suggests the chemical “reactivity” of the produced slaked lime. Raman and XRD results revealed the presence of unburned quantities of calcite and dolomite on samples that were calcined at 900 0C. Furthermore, temperatures of 1050 and 1200 0C have shown comparable mineralogical features signifying evenly the conversion of carbonate minerals to their oxide equivalents, proving the completion of the calcination process. Finally, reactivity tests showed that the highest reactivity value of the produced quicklime, for both marbles is observed at the temperature of 1050 0C.

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