scholarly journals Evolution of large area TiS2-TiO2 heterostructures and S-doped TiO2 nano-sheets on titanium foils

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. Ahmad Etghani ◽  
E. Ansari ◽  
S. Mohajerzadeh
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Growth Parameters ◽  
Critical Role ◽  
Chemical Vapor ◽  
Rutile Phase ◽  
Xps Analysis ◽  
Large Area ◽  
Chlorine Gas ◽  
Titanium Foils

AbstractWe report a novel and facile method to synthesize sulfur-doped titanium oxide sheets and realize TiS2-TiO2 heterostructures by means of a sequential sulfurization and oxidation step in a dual-zone chemical vapor deposition furnace. The inclusion of chlorine and argon gases during the growth of such titanium-based compounds plays a critical role in the formation of desired geometries and crystalline structures. These heterostructures possess nano-whisker and nanosheet configurations, controlled by adjusting the growth parameters such as temperature, carrier gas and the sequencing between different steps of the growth. The evolution of these complex heterostructures has been investigated using Raman spectroscopy and EDS characterization. The presence of chlorine gas during the growth results in local TiS2 formation as well as faceted growth of TiO2 nanosheets through anatase to rutile phase change prohibition. The electron microscopy (TEM) images and diffraction pattern (SAED) characterization reveal the crystallinity and layered nature of grown structures, further demonstrating the 2D characteristics of S-doped nanosheets. The evolution of TiO2 on TiS2 heterostructures has also has been verified using XPS analysis. These highly featured nanostructures are suitable candidates to enhance the photocatalytic behavior of TiO2 nanostructures.

scholarly journals Growth of U-Shaped Graphene Domains on Copper Foil by Chemical Vapor Deposition

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1887
Author(s):  
Ming Pan ◽  
Chen Wang ◽  
Hua-Fei Li ◽  
Ning Xie ◽  
Ping Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Growth Parameters ◽  
Copper Substrate ◽  
Chemical Vapor ◽  
Morphology Evolution ◽  
Force Microscopy ◽  
Smooth Edge ◽  
Transmission Electron

U-shaped graphene domains have been prepared on a copper substrate by chemical vapor deposition (CVD), which can be precisely tuned for the shape of graphene domains by optimizing the growth parameters. The U-shaped graphene is characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman. These show that the U-shaped graphene has a smooth edge, which is beneficial to the seamless stitching of adjacent graphene domains. We also studied the morphology evolution of graphene by varying the flow rate of hydrogen. These findings are more conducive to the study of morphology evolution, nucleation, and growth of graphene domains on the copper substrate.

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.

scholarly journals Single Crystalline Iron Silicide and Beta-Iron Disilicide Nanowires Formed through Chemical Vapor Deposition

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2384 ◽  
Author(s):  
Wei-Jie Huang ◽  
Yu-Yang Chen ◽  
Hsiu-Ming Hsu ◽  
Kuo-Chang Lu
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Ohmic Contacts ◽  
Growth Parameters ◽  
Iron Silicide ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Formation Mechanisms ◽  
Iron Disilicide

In this paper, we report the synthesis of iron silicide and β-iron disilicide nanowires with chemical vapor deposition; remarkably, the latter has drawn much attention but has seldom been achieved. We also propose the formation mechanisms for the two phases. To investigate the effects of the growth parameters on compositions and morphologies of the iron silicide nanowires, we changed and studied the reaction time, substrate temperature, position of samples, and pressure. The reaction concentration was found to be altered by all of the parameters; thus, we observed different nanowires in terms of morphologies and compositions with scanning electron microscopy. To confirm the growth direction and crystal structure of the nanowires, we conducted x-ray diffraction and high-resolution transmission electron microscopy studies. With the potential of being utilized as circuit elements in electronic devices for Schottky barriers, ohmic contacts, and interconnection among silicon-based transistors, the silicide work at nanoscale is beneficial for nanoelectronics. Understanding the effects of these growth parameters facilitates the control of nanowire growth with better quality.

Growth of aligned multiwalled carbon nanotubes on bulk copper substrates by chemical vapor deposition

2009 ◽  
Vol 24 (9) ◽  
pp. 2813-2820 ◽  
Author(s):  
Ge Li ◽  
Supriya Chakrabarti ◽  
Mark Schulz ◽  
Vesselin Shanov
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Critical Role ◽  
Copper Substrate ◽  
Chemical Vapor ◽  
Copper Surface ◽  
Multiwalled Carbon ◽  
Ethylene Concentration ◽  
Intermediate Layers

Successful growth of vertically aligned carbon nanotube (CNT) arrays on copper substrate by thermal chemical vapor deposition is reported in this paper. The effects of Ti, Ni, and Ni–Cr intermediate layers have been studied to eliminate cracking of the copper surface during the synthesis of CNTs. It was found that these intermediate layers play a critical role in achieving vertical alignment of CNTs on copper substrates. The effects of other reaction parameters such as flow rate of ethylene, concentration of water vapor, and deposition temperature have also been studied. Scanning electron microscopy, transmission electron microscopy, and micro-Raman spectroscopy were used to evaluate the quality and nature of the CNT formed.

Large-Area Film Structure Consisted by Aggregation of Zinc Oxide Micro-Whiskers

2002 ◽  
Vol 749 ◽  
Author(s):  
Shuji Tokita ◽  
Shigeo Ohshi ◽  
Hidetoshi Saitoh
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Zinc Oxide ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Film Structure ◽  
Large Area ◽  
X Ray ◽  
Oxide Crystals ◽  
Scanning Electron

ABSTRACTWe developed a chemical-vapor deposition (CVD) apparatus with a 0.5×240 mm2 slit-type nozzle that scans at an area of 240×315 mm2 in the atmosphere. This apparatus forms uniform oxide crystals on substrates through the decomposition process of precursors emitted from the nozzle. In this study, ZnO whiskers were synthesized on a single-crystalline 8-inch wafer of (100)-oriented silicon using this apparatus. Morphological and crystallographic properties of the samples were evaluated using scanning electron microscopy and X-ray diffractometry.

Optical Characterization and Mapping of Four INCH InSb Epitaxial thin Films Grown on GaAs by Turbo Disk Metalorganic Chemical Vapor Deposition

1996 ◽  
Vol 450 ◽  
Author(s):  
Z. C. Feng ◽  
C. Beckham ◽  
P. Schumaker ◽  
I. Ferguson ◽  
R. A. Stall ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Growth Parameters ◽  
Thickness Distribution ◽  
Chemical Vapor ◽  
Crystalline Quality ◽  
Large Area ◽  
Metalorganic Chemical

ABSTRACTA large number of 4 inch (100 mm) diameter 1–2 μm thick InSb films have been grown on GaAs by low pressure metalorganic chemical vapor deposition (MOCVD) turbo disk technology. Raman scattering microscopy was used to study the effects of III-V source ratios on the film crystalline quality and to optimize the growth parameters. Multi-point Raman measurements over the entire 4” wafer were performed to exhibit the uniformity distribution of the film crystalline quality. A FTIR reflectance mapping system has been established to map the film thickness distribution. Good uniformity of the film thickness and crystalline perfection was obtained. Raman and FTIR are showing useful tools for non-destructive characterization of large area wafers for industrial mass production.

Synthesis and Characterization of Large Area Carbon Nanotubes Array

2013 ◽  
Vol 750-752 ◽  
pp. 232-235
Author(s):  
Zhi Wang ◽  
Chun Hong Yu
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Tubular Structures ◽  
Large Area ◽  
Aligned Arrays ◽  
Transmission Electron ◽  
Simple Chemical

Large area carbon nanotubes array were synthesized on the quartz glass by a simple chemical vapor deposition. Scanning electron microscopy and transmission electron microscopy were used to evaluate the morphology and structure. The results show that the well-aligned arrays are synthesized and their length can reach millimeter range, these CNTs have varying outer diameters from 20 to 70 nm and display hollow tubular structures.

Transmission Electron Microscopy (TEM) Specimen Preparation Technique using Focused Ion Beam (FIB): Application to Material Characterization of Chemical Vapor Deposition of Tungsten (W) and Tungsten Silicides (WSix)

1997 ◽  
Author(s):  
K. Doong ◽  
J.-M. Fu ◽  
Y.-C. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Electron

Abstract The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.

scholarly journals Thermodynamics Controlled Sharp Transformation from InP to GaP Nanowires via Introducing Trace Amount of Gallium

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhenzhen Tian ◽  
Xiaoming Yuan ◽  
Ziran Zhang ◽  
Wuao Jia ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Driving Force ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Nanowire Growth ◽  
Calphad Approach ◽  
Deposition Method ◽  
Large Area ◽  
Growth Phenomenon

AbstractGrowth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth.

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