scholarly journals CVD Conditions for MWCNTs Production and Their Effects on the Optical and Electrical Properties of PPy/MWCNTs, PANI/MWCNTs Nanocomposites by In Situ Electropolymerization

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 351
Author(s):  
Silvia Beatriz Brachetti-Sibaja ◽  
Diana Palma-Ramírez ◽  
Aidé Minerva Torres-Huerta ◽  
Miguel Antonio Domínguez-Crespo ◽  
Héctor Javier Dorantes-Rosales ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Synergistic Effects ◽  
Chemical Vapor ◽  
Decomposition Temperature ◽  
Processing Temperature ◽  
Crystallinity Degree ◽  
Decomposition Time ◽  
Better Than ◽  
Multiwalled Cnts

In this work, the optimal conditions of synthesizing and purifying carbon nanotubes (CNTs) from ferrocene were selected at the first stage, where decomposition time, argon fluxes, precursor amounts, decomposition temperature (at 1023 K and 1123 K), and purification process (HNO3 + H2SO4 or HCl + H2O2), were modulated through chemical vapor deposition (CVD) and compared to commercial CNTs. The processing temperature at 1123 K and the treatment with HCl + H2O2 were key parameters influencing the purity, crystallinity, stability, and optical/electrical properties of bamboo-like morphology CNTs. Selected multiwalled CNTs (MWCNTs), from 1 to 20 wt%, were electropolymerized through in-situ polarization with conductive polymers (CPs), poly(aniline) (PANI) and poly(pyrrole) (PPy), for obtaining composites. In terms of structural stability and electrical properties, MWCNTs obtained by CVD were found to be better than commercial ones for producing CPs composites. The CNTs addition in both polymeric matrixes was of 6.5 wt%. In both systems, crystallinity degree, related to the alignment of PC chains on MWCNTs surface, was improved. Electrical conductivity, in terms of the carrier density and mobility, was adequately enhanced with CVD CNTs, which were even better than the evaluated commercial CNTs. The findings of this study demonstrate that synergistic effects among the hydrogen bonds, stability, and conductivity are better in PANI/MWCNTs than in PPy/MWCNTs composites, which open a promissory route to prepare materials for different technological applications.

Properties of Thin SiO2 Films with In-Situ Deposition of Poly Si Electrodes

1989 ◽  
Vol 146 ◽  
Author(s):  
Paihung Pan ◽  
Ahmad Kermani ◽  
Wayne Berry ◽  
Jimmy Liao
Keyword(s):  
Electrical Properties ◽  
Breakdown Strength ◽  
Chemical Vapor ◽  
Interface State ◽  
State Density ◽  
In Situ Deposition ◽  
Different Temperatures ◽  
Flatband Voltage ◽  
Si Films

ABSTRACTElectrical properties of thin (12 nm) SiO2 films with and without in-situ deposited poly Si electrodes have been studied. Thin SiO2 films were grown by the rapid thermal oxidation (RTO) process and the poly Si films were deposited by the rapid thermal chemical vapor deposition (RTCVD) technique at 675°C and 800°C. Good electrical properties were observed for SiO2 films with thin in-situ poly Si deposition; the flatband voltage was ∼ -0.86 V, the interface state density was < 2 × 1010/cm2/eV, and breakdown strength was > 10 MV/cm. The properties of RTCVD poly Si were also studied. The grain size was 10-60 rim before anneal and was 50-120 rim after anneal. Voids were found in thin (< 70 nm) RTCVD poly Si films. No difference in either SiO2 properties or poly Si properties was observed for poly Si films deposited at different temperatures.

Improvement of Electrical Properties of Tin Oxide Nanoparticle by Controlling its Surface Structure

2004 ◽  
Vol 818 ◽  
Author(s):  
Sung-Jei Hong ◽  
Jeong-In Han
Keyword(s):  
Electrical Properties ◽  
Surface Structure ◽  
Xrd Analysis ◽  
Processing Temperature ◽  
Synthetic Method ◽  
Pd Nanoparticle ◽  
Hrtem Observation ◽  
Uniform Dispersion

AbstractIn this study, a novel SnO2 nanoparticle was successfully synthesized by controlling its surface structure. The surface structure on the nanoparticle is consistent of Pd and PdO clusters of which size is smaller than 1nm. For uniform dispersion of the clusters, in-situ synthetic method was applied using Sn acetate and Pd acetate. The method enhances uniformity by mixing two elements as an aqueous solution. Also, those materials lower the processing temperature since the removal of organic components is possible below 300°C. HRTEM observation reveals that the size of the synthesized particle is ranged from 2 to 7 nm and the Pd cluster is uniformly distributed in the lattice of SnO2 particle. In fact, XRD analysis certifies the uniform solid solution of the Pd cluster in SnO2 since the localized Pd peak was not found. Specific surface area of the synthesized particle measured with BET surface analyzer exceeded 100 m2/g. Also, the SnO2-5wt%Pd nanoparticle exhibits the excellent change in resistance of 0.62 after aging at 400°C for 5 hours. Also, the electrical properties show very stable phenomena in spite of long- term aging for 400 hours at 400°C. So, the ultrafine SnO2-Pd nanoparticle could be synthesized by using the in-situ synthetic method.

Comparison of (hexafluoroacetylacetonate)Cu(vinyltrimethylsilane) and (hexafluoroacetylacetonate)Cu(allyltrimethylsilane) for metalorganic chemical vapor deposition of copper

1999 ◽  
Vol 14 (3) ◽  
pp. 975-979 ◽  
Author(s):  
Man-Young Park ◽  
Jong-Hoon Son ◽  
Sang-Woo Kang ◽  
Shi-Woo Rhee
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Reactivity ◽  
Chemical Vapor ◽  
Copper Films ◽  
H Nmr ◽  
Metalorganic Chemical ◽  
Better Than

For the metalorganic chemical vapor deposition (MOCVD) of copper, (hfac)Cu(VTMS) (hfac = hexafluoroacetylacetonate, VTMS = vinyltrimethylsilane) and (hfac)Cu(ATMS) (ATMS = allyltrimethylsilane) were compared, and the effect of L ligand in (hfac)Cu–L was examined. It was found by 1H-NMR (nuclear magnetic resonance) that the thermal stability of (hfac)Cu(VTMS) was better than that of (hfac)Cu(ATMS) due to the relatively weak Cu–ATMS bond. From in situ Fourier transform infrared spectroscopy (FTIR) experiments, the formation of Cu(hfac)2, the product of disproportion reaction of Cu(hfac), was observed in the gas phase and (hfac)Cu(ATMS) was found to be more reactive to form Cu(hfac)2. The minimum temperature for the deposition of copper films from (hfac)Cu(ATMS) was as low as 60 °C, which was about 70 °C lower than from (hfac)Cu(VTMS). The grain size of the film deposited with (hfac)Cu(ATMS) was substantially larger than that with (hfac)Cu(VTMS), which showed that the chemical reactivity of the precursor had an influence on the microstructure along with the deposition temperature.

A Parametric Study and Characterization of Porous, Non-Permeable, and Conductive PEGDA-HEMA Hydrogels

2010 ◽  
Author(s):  
Christine Chan ◽  
Shannon Chang ◽  
Hani E. Naguib
Keyword(s):  
Electrical Properties ◽  
Water Content ◽  
Parametric Study ◽  
In Situ Polymerization ◽  
Decomposition Temperature ◽  
Mechanical And Electrical Properties ◽  
Conductive Hydrogels ◽  
Further Development

This study involved the development and characterization of novel porous, non-permeable, and conductive hydrogels. The hydrogels were fabricated with HEMA and crosslinked with PEGDA through a complete parametric study of the synthesis parameters which included water content and crosslinking content. The hydrogels were fabricated using UV photopolymerization and in situ polymerization of PPy, and characterization was conducted with respect to their physical, thermal, mechanical, and electrical properties. The physical properties were analyzed with respect to their swelling ratio and equilibrium water content. The thermal properties were analyzed based on the decomposition temperature and residue weight. The mechanical properties examined the elastic modulus of the hydrogels, and the electrical properties investigated the conductivity of the hydrogels. The relationships observed between the processing, structure, and resulting properties provide the basis for further development and application of these porous, non-permeable, and conductive hydrogels.

Oriented Growth of SrTiO3 Films on Si(100) Substrates Using In—situ Cleaning By Excited Hydrogen

1988 ◽  
Vol 116 ◽  
Author(s):  
Hiroshi Ishiwara ◽  
Kazumutsu Azuma
Keyword(s):  
Electrical Properties ◽  
Epitaxial Growth ◽  
Oriented Growth ◽  
Si Substrates ◽  
Better Than

AbstractIn—situ cleaning of Si surfaces in vacuum was successfully performed using excited hydrogen and it was applied to epitaxial growth of SrTiO3 films on Si(100) substrates. Epitaxial growth of SrTiO3 films was observed under optimum cleaning conditions, however, the epitaxial nature was found to be destroyed for films thicker than 50 nm, which is probably due to the non—stoichiometry of the films. The electrical properties of the initially epitaxial SrTiO3 films grown on the cleaned Si substrates were better than those of polycrystalline ones.

Preliminary EM6 Modifications for in situ Chemical Vapor Deposition

1972 ◽  
Vol 30 ◽  
pp. 624-625
Author(s):  
J. L. Kenty
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Vacuum System ◽  
Contamination Rate ◽  
Pumping System ◽  
Outgassing Rate ◽  
Measured Pressure ◽  
Better Than

An AEI EM6 electron microscope is being modified for in situ chemical vapor deposition. The objective is to observe the nucleation and growth kinetics and structure of silicon deposited by SiH4 gas pyrolysis on substrates of sapphire (single crystal α-Al2O3).An Edwards DCB2 thermoelectrically cooled baffle has been installed using a simple adapter which permitted attachment without drilling or cutting of the EM6 frame or vacuum system. Prior to installation the measured contamination rate was 240Å/min; afterward the contamination rate was less than 100 Å/min.An auxiliary pumping system is mounted to the left rear of the column and attached by a special stainless steel flexible bellows to the pumping port at the rear of the specimen chamber. The auxiliary system has an ultimate presure <1 × 10-6 torr, but the measured pressure in the specimen chamber was no better than 1 × 10-5 torr, due primarily to the high outgassing rate of the beam deflector coil immediately above the specimen chamber.

scholarly journals Low-Temperature Hetero-Epitaxial Growth of Ge on Si by High Density Plasma Chemical Vapor Deposition

2006 ◽  
Vol 934 ◽  
Author(s):  
Malcolm Carroll ◽  
Josephine Sheng ◽  
Jason C. Verley
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Density ◽  
Cmos Process ◽  
Processing Temperature ◽  
Density Plasma

ABSTRACTDemand for integration of optoelectronic functionality (e.g., optical interconnects) with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature (∼ 450°C) germanium deposition processes that may be integrated in to the back-end CMOS process flow. A common challenge to improving the germanium quality is the thermal budget of the in-situ bake, which is used to reduce defect forming oxygen and carbon surface residues. Typical cleaning temperatures to remove significant concentrations of oxygen and carbon have been reported to be approximately 750°C for thermal hydrogen bakes in standard chemical vapor deposition chambers. Germanium device performance using lower peak in-situ cleans (i.e., ∼450°C) has been hampered by additional crystal defectivity, although epitaxy is possible with out complete removal of oxygen and carbon at lower temperatures.Plasma enhanced chemical vapor deposition (PECVD) is used to reduce the processing temperature. Hydrogen plasma assisted in-situ surface preparation of epitaxy has been shown to reduce both carbon and oxygen concentrations and enable epitaxial growth at temperatures as low as ∼150°C. The hydrogen is believed to help produce volatile Si-O and H2O species in the removal of oxygen, although typically this is not reported to occur rapidly enough to completely clear the surface of all oxygen until ∼550°C. In this paper, we describe the use of an in-situ argon/germane high density plasma to help initiate germanium epitaxy on silicon using a peak temperature of approximately 460°C. Germanium is believed to readily break Si-O bonds to form more volatile Ge-O, therefore, argon/germane plasmas offer the potential to reduce the necessary in-situ clean temperature while obtaining similar results as hydrogen in-situ cleans. To the authors knowledge this report is also the first demonstration of germanium epitaxy on silicon using this commercially available high density plasma chamber configuration instead of, for example, remote or electron cyclotron resonance configurations.

Observation of Film Growth Phenomena Using Micromachined Structures

1996 ◽  
Vol 441 ◽  
Author(s):  
F. DiMeo ◽  
R. E. Cavicchi ◽  
S. Sernancik ◽  
J. S. Suchle ◽  
N. H. Tea ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Electrical Properties ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Thin Film Growth ◽  
Materials Processing ◽  
Semiconducting Oxides

AbstractA method of studying thin film growth and materials processing using micromachined Si-based structures is presented. The microsubstrate platforms (called “microhotplates”) allow temperature control during deposition, andin situmonitoring of the electrical properties of connected coatings. The efficiency of the approach is amplified when multiple. Independentlyoperated elements are used in array configurations. Illustrations here involve chemical vapor deposition of semiconducting oxides, but the methodology can be employed to investigate the growth of other classes of materials as well.

Growth of Graphene Layers on Silicon Carbide

2009 ◽  
Vol 615-617 ◽  
pp. 199-202 ◽  
Author(s):  
Wlodek Strupiński ◽  
Rafał Bożek ◽  
Jolanta Borysiuk ◽  
Kinga Kościewicz ◽  
Andrzej Wysmolek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Decomposition Temperature ◽  
Atomic Scale ◽  
Graphene Layers ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

The so-called “growth” of graphene was performed using a horizontal chemical vapor deposition (CVD) hot-wall reactor. In-situ etching in the mixture (H2-C3H8) was performed prior to growth at 1600oC temperature under 100 mbar. Systematic studies of the influence of the decomposition temperature and time, substrates roughness, etching of the substrates, heating rate, SiC dezorientation and other process parameters on the graphene thickness and quality have been conducted. Morphology and atomic scale structure of graphene was examined by Scanning Tunnelling Microscopy (STM), Transmission Electron Microscopy (TEM) and Raman scattering methods.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

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