No AbstractPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38319/1/1687_ftp.pd

Cassoux, Patrick

Chansou, B.

Choukroun, R.

Danjoy, C.

Pellegatta, J. -L.

Rivière, E.

Valade, L.

Applied Organometallic Chemistry

A new one-step method, entitled fluidized-bed metal-organic chemical vapor deposition (FBMOCVD) of preparing highly dispersed metal-supported catalysts is reported. The following complexes were studied and used as CVD precursors in presence of H 2 : [Rh(μ-Cl)(CO) 2 ] 2 , Rh(allyl) 3 , Rh(acac)(CO) 2 , Pd(allyl)(hfac), Pd(allyl)(Cp), Pt(COD)(CH 3 ) 2 . (acac, acetylacetonato; hfac, hexafluoroacetylacetonato; Cp, cyclopentadienyl; COD, cyclooctadienyl). In a first approach, depositions on planar substrates were carried out to establish the best experimental conditions to obtain good-quality deposits. X-ray diffraction, X-ray photo-electron spectroscopy and electron microprobe studies were realized on the resulting thin films. Analyses of the products contained in the gas phase after and during deposition were performed by mass spectrometry and GC–MS. Finally, catalysts prepared by FBMOCVD were characterized by transmission electron microscopy–energy dispersion spectroscopy (TEM–EDS), metal-loading determinations and specific-surface measurements (BET). Dispersed nanosized aggregates were obtained, showing high activities in alkene hydrogenation and alcohol hydrocarbonylation. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38322/1/689_ftp.pd

Hierso, Jean-Cyrille

Serp, Philippe

Feurer, Roselyne

Kalck, Philippe

Deep Blue Documents at the University of Michigan

MOCVD of rhodium, palladium and platinum complexes on fluidized divided substrates: Novel process for one-step preparation of noble-metal catalysts

Amorphous chromium carbonitride coatings with a low nitrogen content (3–8 at%) were deposited by low-pressure MOCVD in the temperature range 573–793 K using Cr(NEt 2 ) 4  as single-source precursor. This poor nitrogen incorporation is in agreement with the trends predicted by thermochemical calculations. XPS data, resistivity measurements and annealing experiments suggest that the films grown at 573 K are contaminated by organic species due to incomplete elimination of the ligands. The films deposited at higher temperature crystallize upon annealing at 873 K to form an orthorhombic ternary chromium carbonitride phase. The major volatile by-products of the MOCVD reaction were analyzed by  1 H and  13 C NMR. Their amount and the quasi-equimolar EtN=CHMe/HNEt 2  ratio suggest that most of the NEt 2  ligands are removed by a stepwise mechanism which probably occurs with other diethylamido complexes of transition metals when they are used as single-source precursors in MOCVD. The incorporation of the metalloid elements in the film is discussed in comparison with recent literature data. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38324/1/691_ftp.pd

Maury, Francis

Ossola, Franco

Low-temperature MOCVD of chromium carbonitride coatings from tetrakis(diethylamido)chromium and pyrolysis mechanism of this single-source precursor

Conventional MOCVD techniques require molecules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., β-diketonates, or classical or functionalized metal alkoxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relationships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight. Aerosol-assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desirable. ‘Stability’ here includes the absence of precipitation which would change the stoichiometry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (β-diketonates, β-ketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed-metal species by self-assembly, thus improving solubility and stability toward moisture. These aspects are illustrated in compositions related to high- T  c  superconductors. Novel copper, yttrium, cerum(IV), barium-copper, yttrium-copper and praseodynium-copper species are reported. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38326/1/693_ftp.pd

Hubert-Pfalzgraf, Liliane G.

Guillon, Hervé

Trends in precursor design for conventional and aerosol-assisted CVD of high- T  c  superconductors

International audienceA new one-step method, entitled fluidized-bed metal-organic chemical vapor deposition (FBMOCVD) of preparing highly dispersed metal-supported catalysts is reported. The following complexes were studied and used as CVD precursors in presence of H 2 : [Rh(m-Cl)(CO) 2 ] 2 , Rh(allyl) 3 , Rh(acac)(CO) 2 , Pd(allyl)(hfac), Pd(allyl)(Cp), Pt(COD)(CH 3) 2. (acac, acetylace-tonato; hfac, hexafluoroacetylacetonato; Cp, cyclopentadienyl; COD, cyclooctadienyl). In a first approach, depositions on planar substrates were carried out to establish the best experimental conditions to obtain good-quality deposits. X-ray diffraction, X-ray photo-electron spectroscopy and electron microprobe studies were realized on the resulting thin films. Analyses of the products contained in the gas phase after and during deposition were performed by mass spectrometry and GC-MS. Finally, catalysts prepared by FBMOCVD were characterized by transmission electron micro-scopy-energy dispersion spectroscopy (TEM-EDS), metal-loading determinations and specific surface measurements (BET). Dispersed na-nosized aggregates were obtained, showing high activities in alkene hydrogenation and alcohol hydrocarbonylation

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MOCVD of rhodium, palladium and platinum complexes on¯uidized divided substrates: Novel process for one-step preparation of noble-metal catalysts

Crossref

Preface

Crystalline and amorphous thin films of tungsten(VI) oxide can be prepared by chemical vapor deposition using a variety of volatile precursors below 500 °C. Deposition parameters for preparation of WO 3  films from tungsten hexacarbonyl [W(CO) 6 ], tungsten hexafluoride (WF 6 ), tungsten ethoxides [W(OEt)  x  ,  x  14= 145, 6] and tetra(allyl)tungsten [W(η 3 -C 3 H 5 ) 4 ] are summarized. The electrochromic behavior of these films is comparable with that observed for WO 3  films prepared by evaporation, sputtering and electrodeposition. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38321/1/688_ftp.pd

Kirss, Rein U.

Meda, Lamartine

Chemical vapor deposition of tungsten oxide

Ceramic thin films containing titanium, vanadium, carbon, oxygen and nitrogen were obtained on steel substrates at 873 K, under nitrogen and helium gases and at low pressure, by chemical vapor deposition (CVD) from two organometallic precursors, CpTiCl 2 N(SiMe 3 ) 2  and Cp 2 VMe 2  (Cp, cyclopentadienyl). Independent TG–DTA–MS and CVD studies of the two precursors showed their ability to co-decompose within compatible temperature and pressure domains. The mechanism of the reactions occurring inside the CVD apparatus was also approached by GC–MS and NMR analyses of the condensed decomposition products. CVD conducted under He gas confirmed that the formation of nitride resulted from the nitrogen atoms of the precursor, but the nitrogen content in the films remained lower than approx. 5%. Higher nitrogen contents (up to 12%) were only obtained when using ammonia as a carrier gas. Both precursors being air- and moisture-sensitive, high-purity CVD equipment was used to reduce oxycarbide formation. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38323/1/690_ftp.pd

Evaluation of the simultaneous use of Cp 2 VMe 2  and CpTiCl 2 N(SiMe 3 ) 2  as precursors to ceramic thin films containing titanium and vanadium: Towards titanium–vanadium carbonitride

Laser-assisted chemical vapor deposition (LCVD) was utilized to produce SnO 2  films from SnBr 4  plus air, O 2  or N 2 O. SnO 2  films were successfully generated using either 222 or 308 14nm laser pulses but there was evidence for film contamination when using less than 60 14mJ/pulse laser energies at 222 14nm. Films were characterized using ultraviolet absorption spectroscopy; the spectra of films with impurities resembled the spectrum of SnBr 4 . AFM images were obtained which indicated that this LCVD route produced small and fairly uniform SnO 2  grains which were 50–100 14nm in size. Multiphoton ionization spectroscopy was used to verify that the dissociation of a film dopant precursor, copper(II) acetate, produced gas-phase copper atoms under conditions similar to those used in film deposition experiments. The deposition of SnO 2  from SnBr 4  plus an oxidant was found to be more efficient than from di-n-butyl tin diacetate but films produced via this new LCVD route, including those doped with copper, were found to be much less sensitive in preliminary gas-sensing screening. © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38320/1/687_ftp.pd

Hossenlopp, Jeanne M.

Lamelas, F. J.

Middleton, Kenneth

Rzepiela, Jeffrey A.

Schmidt, Jason D.

Zivkovic, Aleksandar

Comparison of SnBr 4  and di-n-butyl tin diacetate as laser-assisted chemical vapor deposition precursors for SnO 2 -based gas sensors

Laine, Richard M.

Conventional MOCVD techniques require mole-cules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., b-diketo-nates, or classical or functionalized metal alk-oxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relation-ships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight. Aerosol-assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desir-able. ‘Stability ’ here includes the absence of precipitation which would change the stoichio-metry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (b-diketonates, b-ketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed-metal species by self-assembly, thus improving solu-bility and stability toward moisture. These aspects are illustrated in compositions related to high-Tc superconductors. Novel copper, yt-trium, cerum(IV), barium-copper, yttrium-copper and praseodynium-copper species ar

Liliane G. Hubert-pfalzgraf

Herveâ Guillon

CiteSeerX

Trends in Precursor Design for Conventional and Aerosol-assisted CVD of High-Tc

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/38326/693_ftp.pdf%3Bjsessionid%3D424C954A9FB4569CBDA27987825188A7?sequence%3D1

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Deep Blue Documents at the University of Michigan

Deep Blue Documents at the University of Michigan

Deep Blue Documents at the University of Michigan

HAL-IRD

Crossref

Deep Blue Documents at the University of Michigan

Deep Blue Documents at the University of Michigan

Deep Blue Documents at the University of Michigan

Deep Blue Documents at the University of Michigan

CiteSeerX