Role of RF Power and Gas Mixture in Some Optical and Photoluminescence Properties of Dual-Plasma a-C:H Films

1998 ◽  
Vol 508 ◽  
Author(s):  
T. Heitz ◽  
C. Godet ◽  
J.E. Bouree ◽  
B. Drevillon ◽  
V. Chu ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Plasma Reactor ◽  
Carbon Films ◽  
Polymer Chains ◽  
Visible Range ◽  
Cross Linking ◽  
Rf Power ◽  
Photoluminescence Properties ◽  
Hydrogenated Amorphous

AbstractElectronic properties of polymer-like hydrogenated amorphous carbon films, grown in a RF-assisted microwave plasma reactor, have been studied using optical absorption and photoluminescence spectroscopies. Using a Forouhi-Bloomer parametrization of π-π* transitions, two regimes are evidenced for increasing C atom density : a decrease of the optical gap Eππ* at constant (H/H+C) content attributed to sp2C clustering, followed by some H elimination with minor changes in Eππ* due to cross-linking of polymer chains. The photoluminescence efficiency in the visible range (peak at ≈ 2.3 eV) is found to decrease over four orders of magnitude at the onset of the cross-linking regime. This quenching is attributed to stress-induced non-radiative centers.

Role of microstructure on the oxidation behavior of microwave plasma synthesized diamond and diamond-like carbon films

1990 ◽  
Vol 5 (11) ◽  
pp. 2445-2450 ◽  
Author(s):  
Rao R. Nimmagadda ◽  
A. Joshi ◽  
W. L. Hsu
Keyword(s):  
Oxidation Behavior ◽  
Microwave Plasma ◽  
Natural Diamond ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Gravimetric Analysis ◽  
Oxidation Rates

Oxidation kinetics of microwave plasma assisted CVD diamond and diamond-like carbon (DLC) films in flowing oxygen were evaluated in the temperature range of 500 to 750 °C and were compared with those of graphite and natural diamond. The diamond and DLC films were prepared using CH4/H2 ratios of 0.1, 0.25, 0.5, 1.0, and 2.0%. The films deposited at 0.1% ratio had a faceted crystalline structure with high sp3 content and as the ratio increased toward 2%, the films contained more and more fine crystalline sp2 bonded carbon. The oxidation rates were determined by thermal gravimetric analysis (TGA), which shows that the films deposited at ratios of 2, 1, and 0.5% oxidized at high rates and lie between the rates of natural diamond and graphite. The oxidation rate decreased with lower CH4/H2 ratio and the films deposited at 0.25 and 0.1% exhibited the lowest oxidation rates associated with the highest activation energies in the range of 293–285 kJ/mol · K. The oxidation behavior of microwave plasma assisted diamond films was similar to that of DC plasma assisted CVD diamond films. The results suggest that the same mechanism of oxidation is operational in both DC and microwave plasma assisted diamond films and is probably related to the microstructure and preferred orientation of the crystallites.

Characterization and Tribological Properties of Nanostructured Copper/Carbon Composite Films Prepared by Microwave Plasma-Assisted Dual Deposition Processes

2002 ◽  
Vol 750 ◽  
Author(s):  
François Thiery ◽  
Yves Pauleau ◽  
Jacques Pelletier
Keyword(s):  
Amorphous Carbon ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Composite Films ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Carbon Films ◽  
Radius Of Curvature

ABSTRACTNanocrystalline copper/hydrogenated amorphous carbon films have been deposited on Si substrates at the floating potential using a distributed electron cyclotron resonance microwave plasma reactor. In this deposition technique, the microwave plasma-enhanced chemical vapor deposition process of carbon from argon-methane or argon-acetylene mixtures of various compositions was associated with the sputter deposition of copper from a copper target. The total pressure was fixed at 0.13 Pa. For deposition, the substrates mounted on a water-cooled substrate holder were maintained at ambient temperature. The composition of films determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses was investigated as a function of the gas phase composition. The structure of films was identified by X-ray diffraction (XRD) techniques and the size of copper crystallites incorporated in the amorphous carbon matrix was deduced from XRD data. The magnitude of residual stresses developed in these films was calculated from the radius of curvature of film/substrate samples determined by profilometry. The residual stress values were found to be nearly independent on the composition of films and deposition parameters.

Oxidation of Unvulcanized Cold Rubber Influence of Adsorption by Carbon Black

1952 ◽  
Vol 25 (3) ◽  
pp. 557-572
Author(s):  
C. W. Sweitzer ◽  
Francis Lyon
Keyword(s):  
Carbon Black ◽  
Surface Chemistry ◽  
Carbon Films ◽  
Cross Linking ◽  
Additional Information ◽  
Rubber Compounds ◽  
Repressive Effect ◽  
Solvent Systems ◽  
Dilute System

Abstract Previous investigations have shown a large difference between the amount of rubber insolubilized by carbon black in dilute solvent systems and in standard mill mixes. The purpose of this study, after reconciling these extremes, was to evaluate the role of adsorption in the insolubilization of rubber in mill-mixed compounds. An adsorption test was employed which eliminated the solvent effect of the dilute system and the mastication effect in mill mixing. Results showed that carbon black, depending on the temperature and atmosphere conditions imposed on the rubber carbon films, represses the scission, cross-linking, and gelation reactions of GR-S X-478. This repressive effect is ascribed to the adsorption and inactivation by the carbon black of the oxidized intermediates through which these various reactions proceed. The magnitude of this effect was found to vary with the type, loading, and surface chemistry of the carbon. This approach not only offers promise as a means for predicting the behavior of carbon black in rubber compounds, but also, because of its applicability to the study of all rubber-carbon systems, offers possibilities of providing additional information on the mechanism of the carbon-rubber bond.

Deposition of Hydrogenated Amorphous Carbon Films by an ECR Microwave Plasma

1989 ◽  
Vol 112 (2) ◽  
pp. 667-677 ◽  
Author(s):  
W. Scharff ◽  
K. Hammer ◽  
B. Eibisch ◽  
O. Stenzel ◽  
S. Roth ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Microwave Plasma ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Hydrogenated Amorphous Carbon ◽  
Hydrogenated Amorphous

scholarly journals CO2 Conversion in a Microwave Plasma Reactor in the Presence of N2: Elucidating the Role of Vibrational Levels

2015 ◽  
Vol 119 (23) ◽  
pp. 12815-12828 ◽  
Author(s):  
Stijn Heijkers ◽  
Ramses Snoeckx ◽  
Tomáš Kozák ◽  
Tiago Silva ◽  
Thomas Godfroid ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Plasma Reactor ◽  
Co2 Conversion ◽  
Vibrational Levels

Investigation of the Optical Properties of Diamond-Like Carbon Films

1997 ◽  
Vol 498 ◽  
Author(s):  
B. K. Kim ◽  
T. A. Grotjohn
Keyword(s):  
Optical Properties ◽  
Plasma Reactor ◽  
Ionic Species ◽  
Carbon Films ◽  
Film Properties ◽  
Ecr Plasma ◽  
Argon Ions ◽  
Hydrogenated Amorphous ◽  
Ion Species ◽  
Deposition Conditions

ABSTRACTHydrogenated-amorphous carbon films are deposited in a microwave ECR plasma reactor with an rf biased substrate holder using methane-argon and acetylene-argon gas mixtures. The film's optical properties are characterized versus deposition conditions including pressure (1–5 mTorr), rf induced bias (-100 to 20 volts), and argon/hydrocarbon flow ratio. The acetylene-argon discharges show that ion species formed from acetylene are more important than the argon ions, conversely, the methane-argon discharges showed that argon ions are a major ionic species in the deposition. The influence of the thickness of insulating substrates is studied and the feasibility of depositing multilayer a-C:H films with different film properties in each layer is demonstrated.

Boron-doped hydrogenated amorphous carbon films grown by surface-wave mode microwave plasma chemical vapor deposition

2006 ◽  
Vol 15 (11-12) ◽  
pp. 1909-1912 ◽  
Author(s):  
Sudip Adhikari ◽  
Dilip C. Ghimire ◽  
Hare Ram Aryal ◽  
Sunil Adhikary ◽  
Hideo Uchida ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Wave Mode ◽  
Carbon Films ◽  
Plasma Chemical ◽  
Amorphous Carbon Films ◽  
Plasma Chemical Vapor Deposition ◽  
Boron Doped ◽  
Hydrogenated Amorphous

Control of the Luminescence Properties in Polythiophenes Solutions by Interring Rotational Disorder

1997 ◽  
Vol 488 ◽  
Author(s):  
S. Luzzati ◽  
G. Bongiovanni ◽  
M. Catellani ◽  
M. A. Loi ◽  
A. Milani ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Luminescence Spectra ◽  
Visible Range ◽  
Optical Absorption Spectra ◽  
Photoluminescence Properties ◽  
Dilute Solutions ◽  
Thiophene Based Polymers

AbstractThe photoluminescence properties of thiophene-based polymers obtained by the random copolymerization of 3,4-dibutylthiophene and 3-butylthiophene are reported. Optical absorption spectra, cw photolumninescence (PL) spectra, PL quantum efficiencies and PL decays have been measured in dilute solutions. By varying the copolymer chemical composition it is possible to tune the intensity and the color of the luminescence spectra in the whole visible range. We evidence the role of disorder, controlled by interring rotations, as the tuning factor for the disexcitation pathway of the photoexcitations in these materials.

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