Toward the High-Quality Graphene for Optoelectronic Applications by Optimization of the Growth and Transfer Parameters

2013 ◽  
Vol 834-836 ◽  
pp. 33-36
Author(s):  
Lang Wang ◽  
Jian Hua Zhang ◽  
Lian Qiao Yang
Keyword(s):  
Surface Condition ◽  
Chemical Vapor ◽  
Reflow Process ◽  
High Quality ◽  
Cu Substrate ◽  
Nucleation Sites ◽  
Higher Temperature ◽  
Transfer Parameters ◽  
Optoelectronic Applications ◽  
Pre Treatment

In this paper, the process parameters of graphene during fabrication and transfer are investigated. Cu is utilized as the substrate and chemical vapor deposition are used to obtain graphene. The results show that, the surface condition of the Cu substrate tends to be worse than as-received after a relatively higher temperature (1035°C) annealing and growth process, which lead to bad graphene quality. In addition, pre-treatment of Cu substrate by acetic acid is helpful to reduce the nucleation sites. Reflow process before PMMA etching is an effective method to eliminate the wrinkles formed during transfer. High-quality graphene for optoelectronic applications were obtained based on the optimized fabrication and transfer process.

High-quality graphene transfer via directional etching of metal substrates

Nanoscale ◽  
2019 ◽  
Vol 11 (34) ◽  
pp. 16001-16006 ◽  
Author(s):  
Xuewei Zhang ◽  
Zehao Wu ◽  
Haoran Zheng ◽  
Qiancheng Ren ◽  
Zhenxing Zou ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
High Quality ◽  
Metal Substrates ◽  
Cu Substrate ◽  
Chemical Vapor Deposited ◽  
Graphene Transfer

The quality of chemical-vapor-deposited graphene can be significantly improved by directional removal of the underlying Cu substrate.

Synthesis of diamond films on Hastelloy

1992 ◽  
Vol 7 (10) ◽  
pp. 2785-2790 ◽  
Author(s):  
V.P. Godbole ◽  
J. Narayan
Keyword(s):  
Diamond Film ◽  
Composite Layer ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Diamond Growth ◽  
Chemical Vapor Deposition Method ◽  
Nucleation Sites ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Hot Filament

We have developed a two-step hot filament chemical vapor deposition method to form polycrystalline films of diamond on Hastelloy substrates. The first step at a lower temperature results in the deposition of a composite layer of carbon, diamond-like carbon, and diamond, which provide nucleation sites for diamond growth in the second step at a higher temperature. To obtain a cleaner amorphous carbon-free diamond film, we introduced an intermediate hydrogen etching step. Using this procedure, we have obtained high quality polycrystalline diamond film on Hastelloy substrates, as characterized by scanning electron microscopy and Raman measurements.

scholarly journals Multiwalled carbon nanotubes synthesis from methane using a stainless steel foils as a catalyst

2021 ◽  
Vol 10 (1) ◽  
pp. 54-58
Author(s):  
Thuan Huynh Minh ◽  
Sura Nguyen ◽  
Ngan Nguyen Thi Kim ◽  
Huan Nguyen Manh ◽  
Noa Uy Do Pham ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Chemical Vapor ◽  
Treatment Temperature ◽  
Multiwalled Carbon ◽  
Nucleation Sites ◽  
Pre Treatment ◽  
20 Nm ◽  
Stainless Steel Foils ◽  
Steel Foils

In this study, a thin stainless-steel foil was used as a catalyst for carbon nanotubes (CNTs) using methane as a carbon source via the chemical vapor deposition (CVD) method. Our results revealed that pre-treatment step of the catalyst plays an important role in CNT formation. In our experiments, a catalyst pre-treatment temperature of 850 oC have been found to facilitate the surface roughness and provide more active nucleation sites for CNTs formation. Multiwalled CNTs with 6 layers, their diameters of 10 – 20 nm and their length of app. 300 nm were grown. This finding might lead to a process for improving the quality of MWCNTs grown on steel foil as catalyst.

scholarly journals Multiwalled carbon nanotubes synthesis from methane using a stainless steel foils as a catalyst

2020 ◽  
Vol 9 (3) ◽  
pp. 27-30
Author(s):  
Thuan Huynh Minh ◽  
Sura Nguyen ◽  
Ngan Nguyen Thi Kim ◽  
Huan Nguyen Manh ◽  
Uy Do Pham Noa ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Stainless Steel ◽  
Chemical Vapor ◽  
Treatment Temperature ◽  
Multiwalled Carbon ◽  
Nucleation Sites ◽  
Pre Treatment ◽  
20 Nm ◽  
Stainless Steel Foils ◽  
Steel Foils

In this study, a thin stainless-steel foil was used as a catalyst for carbon nanotubes (CNTs) using methane as a carbon source via the chemical vapor deposition (CVD) method. Our results revealed that pre-treatment step of the catalyst plays an important role in CNT formation. In our experiments, a catalyst pre-treatment temperature of 850 oC have been found to facilitate the surface roughness and provide more active nucleation sites for CNTs formation. Multiwalled CNTs with 6 layers, their diameters of 10 – 20 nm and their length of app. 300 nm were grown. This finding might lead to a process for improving the quality of MWCNTs grown on steel foil as catalyst.

High Rate Deposition of Stable Hydrogenated Amorphous Silicon in Transition from Amorphous to Microcrystalline Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Guofu Hou ◽  
Xinhua Geng ◽  
Xiaodan Zhang ◽  
Ying Zhao ◽  
Junming Xue ◽  
...  
Keyword(s):  
Phase Transition ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
High Rate ◽  
Very High Frequency ◽  
High Quality ◽  
Working Pressure ◽  
Hydrogen Dilution ◽  
Hydrogenated Amorphous

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.

The Formability and Elongation of Aluminum Alloys AA5083 and AA3003 for Micro-Truss Sandwiches Manufacturing

2020 ◽  
Vol 38 (9A) ◽  
pp. 1396-1405
Author(s):  
Arwa F. Tawfeeq ◽  
Matthew R. Barnett
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Cost Effective ◽  
Tensile Tests ◽  
Truss Structures ◽  
High Quality ◽  
Trade Off ◽  
Clad Layer ◽  
Higher Temperature ◽  
Different Shapes

The development in the manufacturing of micro-truss structures has demonstrated the effectiveness of brazing for assembling these sandwiches, which opens new opportunities for cost-effective and high-quality truss manufacturing. An evolving idea in micro-truss manufacturing is the possibility of forming these structures in different shapes with the aid of elevated temperature. This work investigates the formability and elongation of aluminum alloy sheets typically used for micro-truss manufacturing, namely AA5083 and AA3003. Tensile tests were performed at a temperature in the range of 25-500 ○C and strain rate in the range of 2x10-4 -10-2 s-1. The results showed that the clad layer in AA3003 exhibited an insignificant effect on the formability and elongation of AA3003. The formability of the two alloys was improved significantly with values of m as high as 0.4 and 0.13 for AA5083 and AA3003 at 500 °C. While the elongation of both AA5083 and AA3003 was improved at a higher temperature, the elongation of AA5083 was inversely related to strain rate. It was concluded that the higher the temperature is the better the formability and elongation of the two alloys but at the expense of work hardening. This suggests a trade-off situation between formability and strength. 

scholarly journals Evolution of High-Quality Homoepitaxial CVD Diamond Films Induced by Methane Concentration

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 888
Author(s):  
Pengfei Zhang ◽  
Weidong Chen ◽  
Longhui Zhang ◽  
Shi He ◽  
Hongxing Wang ◽  
...  
Keyword(s):  
Methane Concentration ◽  
Flat Surface ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Plasma Chemical ◽  
High Quality ◽  
Effect Analysis ◽  
Plasma Chemical Vapor Deposition ◽  
Atomically Flat

In this paper, we successfully synthesized homoepitaxial diamond with high quality and atomically flat surface by microwave plasma chemical vapor deposition. The sample presents a growth rate of 3 μm/h, the lowest RMS of 0.573 nm, and the narrowest XRD FWHM of 31.32 arcsec. An effect analysis was also applied to discuss the influence of methane concentration on the diamond substrates.

Preparation and Characrization of Tic/C Composite Fiber by Chemical Vapor Deposition

2012 ◽  
Vol 455-456 ◽  
pp. 935-938
Author(s):  
Hai Quan Wang
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Fibers ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Composite Fiber ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Tic Particle ◽  
Higher Temperature

- TiC/C composite fibers were prepared by vapor phase titanizing of the regular carbon fibers via chemical vapor deposition (CVD). The carbon fibers were titanized from the surface of the fiber to the core. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were applied to characterize the morphology and structure of the TiC/C composite fibers. The influences of CVD reaction conditions such as temperature and reaction time on the TiC particle size and the thickness of the deposited layer were investigated. Higher temperature and longer time resulted in the growth of bigger size of the TiC crystal particles, and the particle uniformity was also decreased.

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