scholarly journals Preparation and Characterization of Electrolessly Deposited Platimum and Palladium Nanoparticles on Pyrolyzed Photoresist Films on Silicon Substrates

2002 ◽  
Vol 1 (1) ◽  
Author(s):  
Vivian Liang ◽  
Raymond Chan ◽  
Oliver Chyan
Keyword(s):  
Electron Transfer ◽  
Metal Nanoparticles ◽  
Palladium Nanoparticles ◽  
Metal Ion ◽  
Carbon Film ◽  
Carbon Films ◽  
Ion Concentration ◽  
Silicon Substrates ◽  
Production Of Hydrogen ◽  
Pyrolyzed Photoresist

The effects of metal depositions on pyrolyzed photoresist films (PPF) grown on silicon substrates were investigated. A silicon chip, spin-coated with a positive photoresist was pyrolyzed through heating to form a PPF, or a conductive carbon film. For increasing periods of time, nanometersized metal particles of platinum and palladium were spontaneously deposited on conductive carbon films by immersion in solutions of 0.049% HF containing 100 ppm, 200 ppm, and 500 ppm concentrations of metal ions Pt2+ or Pd2+. Following each hour of deposition, the electrochemical behavior of the metal-deposited carbon films were investigated by cyclic voltammetry, utilizing a 0.1 M H2SO4 electrolyte system. The electron-transfer rates and characteristics of hydrogen evolution exhibited positive catalytic effects when the platinum and palladium nanoparticles were deposited on the carbon films. Scanning electron microscopy and energy-dispersive x-ray analysis were employed to characterize the surface morphology and distribution of metal nanoparticles on the PPF surface based on metal ion concentration and deposition time. The depositions of metal nanoparticles accelerate the electron transfer process, which could improve the efficiency and performance of PPF electrodes in the production of hydrogen fuel.

scholarly journals Field Emission from Carbon Films Deposited by Controlled-Low-Energy Beams and CVD Sources

1999 ◽  
Vol 585 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Vladimir I. Merkulov ◽  
L. R. Baylor ◽  
G. E. Jellison ◽  
D. B. Poker ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Morphology ◽  
Field Emission ◽  
Metal Ion ◽  
Ion Beam ◽  
Pyrolytic Graphite ◽  
Carbon Film ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Damage Site

AbstractThe principal interests in this work are energetic-beam control of carbon-film properties and the roles of doping and surface morphology in field emission. Carbon films with variable sp3-bonding fraction were deposited on n-type Si substrates by ArF (193 nm) pulsed-laser ablation (PLA) of a pyrolytic graphite target, and by direct metal ion beam deposition (DMIBD) using a primary Cs+ beam to generate the secondary C- deposition beam. The PLA films are undoped while the DMIBD films are doped with Cs. The kinetic energy (KE) of the incident C atoms/ions was controlled and varied over the range from ∼25 eV to ∼175 eV. Earlier studies have shown that C films' sp3-bonding fraction and diamond-like properties can be maximized by using KE values near 90 eV. The films' surface morphology, sp3–bonding fraction, and Cs-content were determined as a function of KE using atomic force microscopy, TEM/EELS, Rutherford backscattering and nuclear reaction measurements, respectively. Field emission (FE) from these very smooth undoped and Cs-containing films is compared with the FE from two types of deliberately nanostructured carbon films, namely hot-filament chemical vapor deposition (HF-CVD) carbon and carbon nanotubes grown by plasma-enhanced CVD. Electron field emission (FE) characteristics were measured using ∼25-μm, ∼5-μm and ∼1-μm diameter probes that were scanned with ∼75 nm resolution in the x-, y-, and z-directions in a vacuum chamber (∼5 × 10-7 torr base pressure) equipped with a video camera for viewing. The hydrogen-free and very smooth a-D or a-C films (with high or low sp3 content, and with or without ∼1% Cs doping) produced by PLD and DMIBD are not good field emitters. Conditioning accompanied by arcing was required to obtain emission, so that their subsequent FE is characteristic of the arc-produced damage site. However, deliberate surface texturing can eliminate the need for conditioning, apparently by geometrical enhancement of the local electric field. But the most promising approach for producing macroscopically flat FE cathodes is to use materials that are highly nanostructured, either by the deposition process (e.g. HF-CVD carbon) or intrinsically (e.g. carbon nanotubes). HF-CVD films were found to combine a number of desirable properties for FE displays and vacuum microelectronics, including the absence of conditioning, low turn-on fields, high emission site density, and apparent stability and durability during limited long-term testing. Preliminary FE measurements revealed that vertically aligned carbon nanotubes are equally promising.

Micro-Indentation and Micro-Scratch Tests on Sub-Micron Carbon Films

1988 ◽  
Vol 130 ◽  
Author(s):  
T. W. Wu ◽  
R. A. Burn ◽  
M. M. Chen ◽  
P. S. Alexopoulos
Keyword(s):  
Carbon Film ◽  
Carbon Films ◽  
Silicon Substrates ◽  
Argon Sputtering ◽  
Scratch Tests ◽  
Sputtering Pressure ◽  
Micro Indentation ◽  
Poor Adhesion ◽  
Mtorr Argon ◽  
Hardness Depth

AbstractMicro-indentation and micro-scratch techniques were used to characterize the hardness and the adhesion strength of 0.11 μm thick sputtered carbon f-ilms on Silicon substrates. Hardness depth profiles and critical loads were measured using a microindenter under indentation and scratch testing modes, respectively. The carbon film with 6 mtorr argon sputtering pressure shows better practical adhesion (or higher critical load) and slightly higher hardness. The indentation fracture phenomenon observed on the 30 mtorr film is closely related to its poor adhesion. The failure mechanism will also be discussed.

NITROGEN DOPING IN CAMPHORIC CARBON FILMS AND ITS APPLICATION TO PHOTOVOLTAIC CELL

2005 ◽  
Vol 12 (01) ◽  
pp. 35-39 ◽  
Author(s):  
M. RUSOP ◽  
M. MOMINUZZAMAN ◽  
T. SOGA ◽  
T. JIMBO ◽  
M. UMENO
Keyword(s):  
Carbon Film ◽  
Single Crystal Silicon ◽  
Photovoltaic Cell ◽  
Carbon Layer ◽  
Carbon Films ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
N Content ◽  
Optical Gap ◽  
N Incorporation

Carbon films have been deposited on quartz and single-crystal silicon substrates by pulsed laser deposition technique. The soot for the target was obtained from burning camphor, a natural source. The effect of nitrogen (N) incorporation in camphoric carbon film is investigated. Optical gap for the undoped film is about 0.95 eV. The optical gap remains unchanged for low N content and decreases to about 0.7 eV. With higher N content, the optical gap increases. The resistivity of the carbon film increases with N content, initially and decreases with higher N content up till the film that is deposited at 30 mTorr. The results indicate successful doping for the film deposited at low nitrogen content. The J–V characteristics of N-incorporated carbon/silicon photovoltaic cells under illumination are observed to improve upon N-incorporation in the carbon layer.

Catalysis with Transition Metal Nanoparticles of Different Shapes

2005 ◽  
Vol 900 ◽  
Author(s):  
Radha Narayanan ◽  
Mostafa A. El-Sayed
Keyword(s):  
Electron Transfer ◽  
Metal Nanoparticles ◽  
Palladium Nanoparticles ◽  
Transfer Reaction ◽  
Ostwald Ripening ◽  
Suzuki Reaction ◽  
Electron Transfer Reaction ◽  
Different Shapes ◽  
Colloidal Metal ◽  
Shape And Size

ABSTRACTColloidal metal nanoparticles have a high surface-to-volume ratio which makes them potentially attractive catalysts. Furthermore, atoms located at different facets, edges, or corners could show different catalytic activity. For this reason, different shapes could have different catalytic activities. In addition, surface atoms are so active that there could be significant changes in their shape and size during the course of nanocatalysis. As a result, a thorough examination on the effect of the catalytic process on the shape and size of colloidal metal nanoparticles after catalysis is necessary to fully evaluate their use in catalytic processes.In this paper, we briefly review our recent work on examining the shape dependence of nanocatalysis as well as the stability of platinum and palladium nanoparticles during the course of two reactions: the electron transfer reaction and the Suzuki reaction. It is found that nanocatalysis is indeed shape-dependent during the early stages of the electron transfer reaction. During the full course of the reaction, there are changes in the nanoparticle shape as well as changes in the activation energy that takes place. In the case of a relatively harsh reaction such as the Suzuki reaction, spherical palladium nanoparticles grow in size due to Ostwald ripening processes. Tetrahedral platinum nanoparticles catalyzing the Suzuki reaction transform into spherical shape and grow larger in size. We also conducted studies on the effect of individual reactants on the nanoparticle size and shape. In addition, the surface catalytic mechanisms of the reactions have been confirmed using spectroscopic tools such as FTIR and Raman spectroscopy. These kinds of studies will be very useful in the process of designing better nanocatalysts in the future.

Interfacial adhesion and friction of pyrolytic carbon thin films on silicon substrates

2008 ◽  
Vol 23 (10) ◽  
pp. 2749-2756 ◽  
Author(s):  
N. Deyneka-Dupriez ◽  
U. Herr ◽  
H-J. Fecht ◽  
A. Pfrang ◽  
Th. Schimmel ◽  
...  
Keyword(s):  
Residence Time ◽  
Interfacial Adhesion ◽  
Elastic Recovery ◽  
Carbon Film ◽  
Pyrolytic Carbon ◽  
Carbon Films ◽  
Normal Displacement ◽  
Silicon Substrates ◽  
Scratch Testing ◽  
Interface Failure

Frictional behavior and interfacial adhesion of differently textured pyrolytic carbon layers on Si substrate were investigated by indentation and scratch testing. A large amount of elastic recovery and a low coefficient of friction (μ = 0.05 to 0.09) were observed. Elastic/plastic and frictional behaviors of the coatings are strongly influenced by the microstructure of the pyrolytic carbon films, especially by the texture. The critical load at which the first abrupt increase in the normal displacement occurs was used to characterize interfacial adhesive strength. A pyrolytic carbon film deposited at higher residence time from a gas mixture containing 3% oxygen exhibited higher critical loads than film deposited at lower residence time without oxygen. The results can be understood if one assumes that the gas phase composition during deposition significantly influences the bonding strength at the interface. Failure mechanisms are discussed for both types of films.

INFLUENCE OF ELECTROLYTIC PULSE FREQUENCY ON THE PROPERTY OF NANO CARBON FILM DEPOSITED IN MOLTEN SALT

2005 ◽  
Vol 19 (01n03) ◽  
pp. 589-591
Author(s):  
L. FANG ◽  
F. XIAO ◽  
L. C. YANG ◽  
J. ZHANG ◽  
G. B. LIU
Keyword(s):  
Vibration Frequency ◽  
Natural Vibration ◽  
Carbon Film ◽  
Pulse Frequency ◽  
Carbon Films ◽  
Ion Concentration ◽  
Electrolytic Deposition ◽  
Natural Vibration Frequency ◽  
Nickel Substrate ◽  
Nano Carbon

Nano carbon film was synthesized on a nickel substrate in molten LiCl - KCl - K 2 CO 3 salt by an electrolytic deposition method. The influence of pulse frequency on the property of the carbon films was studied. Over the carbonate ion concentration range of 0.10–0.20 mol%, the mass of carbon film on unit area increases with increasing pulse frequency over the range of 0.05–33Hz or 33–166Hz, whereas, it decreases with increasing pulse frequency over the range of 33-166Hz. It means that a critical pulse frequency exists, which can be thought to correspond to the natural vibration frequency of the film. When the electrolytic pulse frequency is equal to the natural vibration frequency of film, a resonance maybe happen, and the film exfoliates.

Benzylamine Tartrate as an Organic Glass Substrate for Carbon Films by Evaporation

1970 ◽  
Vol 28 ◽  
pp. 484-485
Author(s):  
A. C. Faberge
Keyword(s):  
Vapor Pressure ◽  
Viscous Liquid ◽  
Glass Substrate ◽  
Room Temperature ◽  
Carbon Film ◽  
Carbon Films ◽  
Organic Glass ◽  
Spectroscopic Examination ◽  
Polymeric Substrates

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.

Carbon Film Deposition On Silicon Using Low Energy Ion Beams

1991 ◽  
Vol 223 ◽  
Author(s):  
Qin Fuguang ◽  
Yao Zhenyu ◽  
Ren Zhizhang ◽  
S.-T. Lee ◽  
I. Bello ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ion Beam ◽  
Carbon Film ◽  
Carbon Films ◽  
Film Deposition ◽  
Ion Energy ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Post Implantation ◽  
Beam Deposition

ABSTRACTDirect ion beam deposition of carbon films on silicon in the ion energy range of 15–500eV and temperature range of 25–800°C has been studied using mass selected C+ ions under ultrahigh vacuum. The films were characterized with X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy and diffraction analysis. Films deposited at room temperature consist mainly of amorphous carbon. Deposition at a higher temperature, or post-implantation annealing leads to formation of microcrystalline graphite. A deposition temperature above 800°C favors the formation of microcrystalline graphite with a preferred orientation in the (0001) direction. No evidence of diamond formation was observed in these films.

Use of agro-waste (Musa paradisiaca peels) as a sustainable biosorbent for toxic metal ions removal from contaminated water

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Contact Time ◽  
Metal Ion ◽  
Equilibrium Concentration ◽  
Ion Concentration ◽  
Contaminated Water ◽  
Musa Paradisiaca ◽  
Percentage Removal ◽  
Adsorbent Dose

A study of removal of heavy metal ions from heavy metal contaminated water using agro-waste was carried out with Musa paradisiaca peels as test adsorbent. The study was carried by adding known quantities of lead (II) ions and cadmium (II) ions each and respectively into specific volume of water and adding specific dose of the test adsorbent into the heavy metal ion solution, and the mixture was agitated for a specific period of time and then the concentration of the metal ion remaining in the solution was determined with Perkin Elmer Atomic absorption spectrophotometer model 2380. The effect of contact time, initial adsorbate concentration, adsorbent dose, pH and temperature were considered. From the effect of contact time results equilibrium concentration was established at 60minutes. The percentage removal of these metal ions studied, were all above 90%. Adsorption and percentage removal of Pb2+ and Cd2+ from their aqueous solutions were affected by change in initial metal ion concentration, adsorbent dose pH and temperature. Adsorption isotherm studies confirmed the adsorption of the metal ions on the test adsorbent with good mathematical fits into Langmuir and Freundlich adsorption isotherms. Regression correlation (R2) values of the isotherm plots are all positive (>0.9), which suggests too, that the adsorption fitted into the isotherms considered.

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