Fabrication of High-Density Carbon-Nanotube Coatings on Microstructured Substrates

2000 ◽  
Vol 621 ◽  
Author(s):  
Zheng Chen ◽  
Yonhua Tzeng ◽  
Chao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Active Surface ◽  
Deposition Process ◽  
Ultra High Vacuum ◽  
Active Surface Area ◽  
Field Emission Properties ◽  
Ni Substrate

ABSTRACTFabrication and characterization of carbon nanotubes deposited on microstructured Ni substrate are presented. The highly active surface-area of the microstructured Ni substrate provides highdensity nucleation sites for carbon nanotubes. Coated fine Ni powder also serves as a catalyst for the nanotube growth. Hydrocarbon mixtures were used as the carbon source for the chemical vapor deposition process. Carbon nanotubes deposited on the microstructured Ni substrate were examined by SEM. An ultra high vacuum chamber was used to characterize the field emission properties of carbon nanotube coatings.

Growth of Carbon Nanotubes on Copper Substrates Using a Nickel Thin Film Catalyst

2009 ◽  
Vol 1204 ◽  
Author(s):  
Gowtam Atthipalli ◽  
Prashant Kumta ◽  
Wei Wang ◽  
Rigved Epur ◽  
Prashanth H Jampani ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Nickel Catalyst ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Thin Film Catalyst ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

AbstractCarbon nanotubes with their attractive properties, one-dimensional character, and their large aspect ratio are ideal candidates for a variety of applications including energy storage, sensing, nanoelectronics, among others. We have studied the growth of carbon nanotubes on copper substrates using a nickel thin film as a catalyst. The catalyst was sputtered in a chamber having a base pressure in the ultra-high-vacuum regime. By adjusting the sputtering parameters, the effects of the morphology and the thickness of the nickel catalyst on the growth of carbon nanotubes have also been investigated. Multiple hydrocarbon sources as carbon feedstock (methane, acetylene and xylene) and corresponding catalyst precursors and varying temperature conditions were used during the Chemical Vapor Deposition (CVD) process to understand and best determine the ideal conditions for carbon nanotube growth on copper. Correlation between the thickness of the thin film nickel catalyst and the carbon nanotube diameter is also presented in the study. Characterization techniques used to study the morphology of the CNTs grown on copper include SEM, TEM and HRTEM, Raman Spectroscopy

Progress on nanoparticle-based carbon nanotube complex: fabrication and potential application

2016 ◽  
Vol 36 (4) ◽  
Author(s):  
Amin Termeh Yousefi ◽  
Minoru Fukumori ◽  
Pandey Reetu Raj ◽  
Polin Liu ◽  
Lingxiang Fu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Surface Area ◽  
Nanostructured Materials ◽  
Potential Application ◽  
Active Surface ◽  
Semiconductor Nanoparticles ◽  
Active Surface Area ◽  
Recent Developments ◽  
Magnetic Applications

AbstractCarbon nanotubes (CNTs) are considered as one of the most intensively explored nanostructured materials and have been widely used as a platform material for metal and semiconductor nanoparticles (NPs) due to their large and chemically active surface area. Several approaches have been described in the literature to immobilize NPs on the surface of CNTs. This report reviews the recent developments in this area by exploring the various techniques where nanotubes can be functionalized with NPs to improve the optical, mechanical, thermal, medical, electrical, and magnetic applications of CNTs.

Development of Ultra-Clean Plasma Deposition Process

1999 ◽  
Vol 557 ◽  
Author(s):  
Toshihiro Kamei ◽  
Akihisa Matsuda
Keyword(s):  
Grain Size ◽  
Secondary Ion Mass Spectrometry ◽  
Plasma Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ultra High Vacuum ◽  
Very High Frequency ◽  
Microscopic Mechanism ◽  
O 10

AbstractWe have developed a new type of ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV/PECVD) system. According to high sensitivity secondary ion mass spectrometry, device quality hydrogenated amorphous silicon (a-Si:H) films deposited at 250°C at a deposition rate of 1 Å/s contains 1015 cm-3 of O, 1015 cm-3 of C, and 1014 cm-3 of N impurities, while low defect hydrogenated microcrystalline silicon (μc-Si:H) films deposited at 200°C at a very low rate of 0.1 Å/s include 1016 cm-3 of O, 1015 cm-3 of C and 1016 cm-3 of N. These are the lowest concentrations of atmospheric contaminants for these kinds of materials observed so far. The essential features of the present UHV/PECVD system are an extremely low outgassing rate of 8×10-9 Torr·s, extremely low partial pressure of contaminant gas species <10-12 Torn, and purification of feed gas SiH4 at “point of use”. These efforts are quite important not only for clarifying the microscopic mechanism of photo-induced degradation in a-Si:H, but also for enlarging the crystalline grain size in μc-Si:H. μc-Si:H with a grain size of ≍1000 Å as determined by Scherrer's formula can be obtained at the higher rate of 1.5 Å/s by utilizing a VHF (Very High Frequency) plasma. The specific origins of impurities in the films are also discussed.

Sub-Half Micron Elevated SourceDrain NMOSFETS by Low Temperature Selective Epitaxial Deposition

1996 ◽  
Vol 429 ◽  
Author(s):  
J. Sun ◽  
R. F. Bartholomew ◽  
K. Bellur ◽  
P. A. O'Neil ◽  
A. Srivastava ◽  
...  
Keyword(s):  
Low Temperature ◽  
Epitaxial Growth ◽  
High Vacuum ◽  
Chemical Vapor ◽  
High Growth ◽  
Deposition Process ◽  
Deep Submicron ◽  
Ultra High Vacuum ◽  
Gas Source ◽  
Drain Bias

AbstractIn this paper we report the first NMOSFETs with elevated S/D selectively deposited by ultra high vacuum rapid thermal chemical vapor deposition (UHV-RTCVD). The deposition process included an in-situ vacuum prebake (750 °C for 10 sec) followed by selective epitaxial growth (SEG) at 800 °C. Si2H6 was used as the silicon gas source instead of the more commonly used SiH4 and SiH2Cl2 in order to achieve high growth rates at low pressure. To prevent nucleation from occurring on insulator surfaces during growth, an etching mechanism was introduced by the addition of Cl2. The gases included 100 sccm of 10% Si2H6 in H2 and 2 sccm of Cl2 at a process pressure of 24 mTorr. An epitaxial growth rate of 160 nm/min has been achieved. The final epi thickness was around 0.1 μm. The S/D junctions were formed via ion implantation into the epi. The subsequent RTA (10 sec at 950 °C) resulted in an effective junction depth about 75 nm beneath the starting Si substrate. Process and device simulations reveal the importance of maintaining a shallow LDD junction for deep submicron devices by using low temperature selective deposition. MOSFETs exhibit good subthreshold characteristics with subthreshold swing of 86 mV/dec at a drain bias of 2.5 V, and threshold variations due to charge sharing and drain-induced-barrierlowering (DIBL) were moderate for Leff down to 0.35 μm. The gate-induced junction leakage current is below 2 pA/μm at a bias of 2.5 V.

Carbon Nanotube Modification Using BaF2 Vapor in Ultra-High Vacuum Environment

2003 ◽  
Vol 782 ◽  
Author(s):  
Francisco Santiago ◽  
Victor H. Gehman ◽  
Karen Long ◽  
Kevin A. Boulais
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Heat Exposure ◽  
Major Change ◽  
Ultra High Vacuum ◽  
Force Microscopy ◽  
Before And After ◽  
Potential Applications

ABSTRACTCarbon nanotubes have attracted significant attention in the scientific community due to their unique properties and potential applications. One of the most promising applications is a carbon-nanotube transistor. The motivation of this work is to find ways to connect carbon nanotubes directly to silicon using Ba as a chemical link. We studied chemical interactions between carbon nanotubes and BaF2 vapors using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Surfaces of silicon wafers were chemically modified to allow the epitaxial growth of BaF2 using molecular beam epitaxy (MBE). Samples containing 2D single crystal islands of BaF2 were covered with carbon nanotubes with an average coverage of 10 nanotubes per um2. The samples were transferred to an outgasing station inside the MBE system and heated to 900°C for two hours in a pressure of 10-9 mbar. XPS C1s data before and after heat show a major change in the nature of the carbon nanotube electronic states. In addition XPS shows formation of a Ba-C “carbide like” bond and no presence of fluorine. AFM images of the same region taken before and after heat exposure show remarkable changes in the surface morphology of the carbon-nanotube wall.

Carbon Nanotube Gas Sensor Fabricated on Anodic Aluminum Oxide

2007 ◽  
Vol 124-126 ◽  
pp. 1309-1312
Author(s):  
Nguyen Duc Hoa ◽  
Nguyen Van Quy ◽  
Gyu Seok Choi ◽  
You Suk Cho ◽  
Se Young Jeong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Gas Sensor ◽  
Chemical Vapor ◽  
Fast Response ◽  
Device Fabrication ◽  
Alumina Oxide ◽  
Response And Recovery ◽  
New Type ◽  
P Type

A new type of gas sensor was realized by directly depositing carbon nanotube on nano channels of the anodic alumina oxide (AAO) fabricated on p-type silicon substrate. The carbon nanotubes were synthesized by thermal chemical vapor deposition at a very high temperature of 1200 oC to improve the crystallinity. The device fabrication process was also developed. The contact of carbon nanotubes and p-type Si substrate showed a Schottky behavior, and the Schottky barrier height increased with exposure to gases while the overall conductivity decreased. The sensors showed fast response and recovery to ammonia gas upon the filling (400 mTorr) and evacuation.

Closed-loop control of a laser assisted carbon nanotube growth process for interconnects in flexible electronics

2011 ◽  
Vol 1365 ◽  
Author(s):  
Yoeri van de Burgt ◽  
Yves Bellouard ◽  
Rajesh Mandamparambil ◽  
Andreas Dietzel
Keyword(s):  
Carbon Nanotube ◽  
Flexible Electronics ◽  
Iron Catalyst ◽  
Chemical Vapor ◽  
Catalyst Layer ◽  
Deposition Process ◽  
Loop Control ◽  
Aluminum Oxide Layer ◽  
Carbon Nanotube Forests ◽  
Carbon Nanotube Growth

ABSTRACTA feedback control mechanism based on infrared radiation monitoring coupled with reflectivity information was developed to control the temperature of a laser assisted chemical vapor deposition process for the growth of carbon nanotube forests. An infrared laser operating at 808 nm is focused on a silicon substrate containing a 20 nm-aluminum-oxide layer and a 1.5 nm-iron catalyst layer. The growth takes place in an argon/ hydrogen/ ethylene gaseous environment. SEM and Raman spectroscopy analysis show that good controllability and reproducibility is achieved over multiple experiments.

Challenge to 200 mm 3C-SiC Wafers Using SOI

2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi
Keyword(s):  
Cross Section ◽  
Vapor Deposition ◽  
Seed Layer ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Average Thickness ◽  
Entire Region ◽  
Transmission Electron ◽  
Good Crystallinity

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

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