Multiphysics, Multiphase Modeling of Carbon Nanotube Synthesis Process by Chemical Vapor Deposition

2007 ◽  
Author(s):  
Mahmoud Reza Hosseini ◽  
Nader Jalili
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Gas Phase ◽  
Production Rate ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Quartz Tube ◽  
Hydrocarbon Gas

In the present paper, a comprehensive modeling framework is proposed to conduct multiphysics, multiphase modeling of carbon nanotube (CNT) fabrication process by chemical vapor deposition (CVD). The modeling is based on fluid dynamics, heat transfer, chemical reaction, as well as mass transport phenomena which have been fully coupled with each other. The inserted gasses are considered as methane (CH4) as the main hydrocarbon gas and hydrogen (H2) as the process enhancement gas. In the gas phase reaction section, a novel set of reactions for CH4 hydrocarbon gas is proposed which is based on 71 different chemical reactions that take place near CVD inlet. Also, surface reactions are modeled by considering 19 set of reactions acting near substrate surface which lead to CNTs formation. The investigation is performed for different combination of gas flow rate quantities ranging from 500 to 1000 sccm (standard cubic centimeter per minute) for methane and 250 to 500 sccm for hydrogen gas. Also, the quartz tube temperature is considered to change from 700 to 1000 °C. Since the thermal specifications for each species are calculated individually, the gas flow inside the quartz tube is treated as nonisothermal flow. Numerous simulations are conducted and the results are compared with the fabricated CNT’s images taken by the SEM (scanning electron microscopy). Utilizing the obtained diagrams from modeling, the effects caused by gas mixture flow rate and temperature changes on the production rate of gas phase species such as H, CH3, C2H2 and bulk carbon species (C and 2C) that produced by surface species TC and TC2 are investigated. It is found that increasing the fabricated temperature causes a rise in species production rate. However, it is observed that the produced species respond differently to any change in hydrogen and hydrocarbon flow rates. The velocity, temperature profile as well as concentration distribution along the silicon substrate length have been also investigated. This study can lead to a controlled CNTs manufacturing process when combined with in-situ measurement systems.

Synthesize of N-doped Carbon nanotube according to gas flow rate by Chemical Vapor Deposition

2011 ◽  
Author(s):  
J. B. Kim ◽  
C. D. Kim ◽  
S. J. Kong ◽  
J. H. Kim ◽  
B. K. Min ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Gas Flow Rate

scholarly journals Numerical Simulation of Gas Phase Reaction for Epitaxial Chemical Vapor Deposition of Silicon Carbide by Methyltrichlorosilane in Horizontal Hot-Wall Reactor

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7532
Author(s):  
Botao Song ◽  
Bing Gao ◽  
Pengfei Han ◽  
Yue Yu ◽  
Xia Tang
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Gas Phase ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Consumption Rate ◽  
Chemical Vapor ◽  
Phase Reaction ◽  
Gas Flow Rate

Methyltrichlorosilane (CH3SiCl3, MTS) has good performance in stoichiometric silicon carbide (SiC) deposition and can be facilitated at relatively lower temperature. Simulations of the chemical vapor deposition in the two-dimensional horizontal hot-wall reactor for epitaxial processes of SiC, which were prepared from MTS-H2 gaseous system, were performed in this work by using the finite element method. The chemistry kinetic model of gas-phase reactions employed in this work was proposed by other researchers. The total gas flow rate, temperature, and ratio of MTS/H2 were the main process parameters in this work, and their effects on consumption rate of MTS, molar fraction of intermediate species and C/Si ratio inside the hot reaction chamber were analyzed in detail. The phenomena of our simulations are interesting. Both low total gas flow rate and high substrate temperature have obvious effectiveness on increasing the consumption rate of MTS. For all cases, the highest three C contained intermediates are CH4, C2H4 and C2H2, respectively, while the highest three Si/Cl contained intermediates are SiCl2, SiCl4 and HCl, respectively. Furthermore, low total gas flow results in a uniform C/Si ratio at different temperatures, and reducing the ratio of MTS/H2 is an interesting way to raise the C/Si ratio in the reactor.

Effects of Reaction Conditions on MoS2 Thin Film Formation Synthesized by Chemical Vapor Deposition using Organic Precursor

MRS Advances ◽  
2016 ◽  
Vol 2 (29) ◽  
pp. 1533-1538 ◽  
Author(s):  
S. Ishihara ◽  
Y. Hibino ◽  
N. Sawamoto ◽  
T. Ohashi ◽  
K. Matsuura ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Film Formation ◽  
Chemical Vapor ◽  
Gas Flow Rate ◽  
Axis Orientation

ABSTRACTMolybdenum disulfide (MoS2) thin films were fabricated by two-step chemical vapor deposition (CVD) using (t-C4H9)2S2 and the effects of temperature, gas flow rate, and atmosphere on the formation were investigated in order to achieve high-speed low-temperature MoS2 film formation. From the results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) investigations, it was confirmed that c-axis orientation of the pre-deposited Mo film has a significant involvement in the crystal orientation after the reaction low temperature sulfurization annealing and we successfully obtained 3 nm c-axis oriented MoS2 thin film. From the S/Mo ratios in the films, it was revealed that the sulfurization reaction proceeds faster with increase in the sulfurization temperature and the gas flow rate. Moreover, the sulfurization under the H2 atmosphere promotes decomposition reaction of (t-C4H9)2S2, which were confirmed by XPS and density functional theory (DFT) simulation.

A Comprehensive Multiphysics, Multiscale Study of Reactor Chamber and Substrate Orientation Effects on Carbon Nanotube Synthesis During Chemical Vapor Deposition Process

2008 ◽  
Author(s):  
Mahmoud Reza Hosseini ◽  
Nader Jalili ◽  
David A. Bruce
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Temperature Profile ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Physical Property ◽  
Fabrication Process ◽  
Multiphase Model ◽  
Gas Phase Reactions

A comprehensive multiphysics, multiphase model of carbon nanotube (CNT) fabrication process by chemical vapor deposition (CVD) is utilized to study the effects of several physical phenomena inside the quartz tube. The investigations include fluid flow properties, temperature profile and heat transfer as well as diffusion and concentration of carbon species along the substrate. These properties are examined in a great detail for a horizontally placed substrate. For each physical property, the effects of substrate dislocation as well as the angle between substrate and reactor chamber longitudinal axis are investigated. It is shown that the temperature in the gas phase reactions region is significantly lower compared to the temperature profile around the substrate. Based on the obtained results, two new CVD system designs are proposed to enhance the temperature in the reactor chamber section where gas phase reactions take place. Moreover, it is shown that substrate dislocation and angle change result in physical property change such as species concentration on upper and lower substrate surfaces. This study is also applicable to other CVD-based fabrication process such as deposition of any layer, since the methodology of the fabrication process remains the same.

Structural and Optical Properties of ZnO Nanotetrapods Deposited by Thermal Chemical Vapor Deposition with Different Gas Flow Rate

2015 ◽  
Vol 1109 ◽  
pp. 456-460
Author(s):  
Najwa Ezira Ahmed Azhar ◽  
Shafinaz Sobihana Shariffudin ◽  
Aimi Bazilah Rosli ◽  
A.K.S. Shafura ◽  
Mohamad Rusop
Keyword(s):  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Gas Flow Rate ◽  
Structural And Optical Properties ◽  
Thermal Chemical Vapor Deposition ◽  
Yellow Orange

ZnO nanotetrapod with different oxygen flow rate was prepared by thermal chemical vapor deposition. We have successfully deposited ZnO nanotetrapod on synthesis Zn powder using double furnace with argon (Ar) and oxygen (O2) gas as source material. In this study, we report the effect of different gas flow rate (5 sccm to 15 sccm) on structural and optical properties of the ZnO nanotetrapod. The morphology of ZnO nanotetrapods were analyzed by field emission scanning electron microscope (FE-SEM). It exhibits the length of the nanotetrapods arm decrease with increased of flow rate and diameter of nanotetrapod in range 30 nm to 90 nm. The optical properties were determined through XRD and photoluminescence with 2θ (30o to 80o) and wavelength 350 nm to 620 nm respectively. PL spectra show that the UV emission centred at 380 nm while yellow-orange emission centred at 540 nm.

Optimization of Super-Long CNT Forests Growth on Conductive Substrate by Water Assisted CVD

2014 ◽  
Vol 496-500 ◽  
pp. 536-540
Author(s):  
Peng Bo Wang ◽  
De Yang Xu ◽  
Li Ning Sun
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Optimum Condition ◽  
Flow Rate ◽  
Growth Temperature ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Conductive Substrate ◽  
Vertically Aligned

Water assisted chemical vapor deposition (CVD) is used widely to synthesize super long, vertically aligned, densely packed carbon nanotube (CNT) forests. Various water assisted CVD parameters give the important influence on the quality of CNT forests. In this paper, several main parameters in water assisted CVD are optimized, such as the flow rate of H2, the content of water and growth temperature. Furthermore, growth on the conductive substrate is also studied by water assisted CVD. Under optimum condition with 10 minutes growth, the length of CNT forests could be 815 μm on silicon substrate and 369 μm on conductive substrate.

Growth Promotion and Etching of Carbon Nanotubes by Carbon Dioxide in Chemical Vapor Deposition using Methane Gas

2007 ◽  
Vol 1057 ◽  
Author(s):  
Yoshiyuki Suda ◽  
Junichi Takayama ◽  
Takeshi Saito ◽  
Atsushi Okita ◽  
Junji Nakamura ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Gas Flow ◽  
Growth Promotion ◽  
Chemical Vapor ◽  
Gas Flow Rate ◽  
Preferential Growth ◽  
Ar Gas ◽  
Walled Cnts

ABSTRACTWe report the effect of CO2 addition to CO4 gas on carbon nanotube (CNT) growth by chemical vapor deposition. CO2 gas was introduced during the growth of CNTs on Fe0.05Mo0.025MgO0.925 and Ni0.05Mo0.025MgO0.925 catalysts by CO4 gas at a temperature of 800–850°C, and its concentration in a fraction of the gas flow rate was varied from 5×10−3 to 50%. In the experimental condition of the preferential growth of multi-walled CNTs, the carbon yield and the G/D ratio in the Raman spectra of the CNTs grown in 10%-CO2/CO4 were slightly higher than that grown in CO4 only. However, CNTs hardly grew when the CO2 concentration was more than 10%. We then prepared CO2 gas diluted with Ar gas (CO2/Ar) and varied its flow rate between 0 and 10 sccm. As the CO2/Ar gas flow rate was increased, the number of RBM peaks decreased even though the G/D ratio gradually decreased. The decrease in the RBM intensities of CNTs on the FeMoMgO catalyst was more significant than that of NiMoMgO.

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