CERIUM β-DIKETONATES

Cerium β-diketonates are one of the most popular precursors for the MOCVD of cerium-contaning layers, due to their high volatility and suitable thermal stability.

Cerium (III) acetylacetonate Ce(acac)3

Cerium (III) acetylacetonate Ce(acac)3 has been applied for the growth of columnar CeO2 and CeO2:Zn thin films by atmospheric pressure MOCVD on quartz and AA6066 aluminum alloy substrates. The films were characterized by XRD, SEM, AFM, TEM and UV–Vis spectroscopy. [[i]]

[i] A.M. Torres-Huerta, M.A. Domínguez-Crespo, S.B. Brachetti-Sibaja, H. Dorantes-Rosales, M.A. Hernández-Pérez, J.A. Lois-Correa

Journal of Solid State Chemistry, Vol. 183, Issue 9, September 2010, Pages 2205–2217

Preparation of ZnO:CeO2–x thin films by AP-MOCVD: Structural and optical properties

http://www.sciencedirect.com/science/article/pii/S0022459610003191

Cerium (IV) acetylacetonate Ce(acac)4

Fig. 1. Molecular structure of β-[Ce(acac)4]. The atomic coordinates are taken from Titze (1969).

Cerium (IV) acetylacetonate Ce(acac)4 has monomeric structure (Fig.1) and has therefore significant volatility, thus potentially usable as MOCVD or ALD precursor of Ce-containing films.

Ce(acac)4 has been studied by TGA and DSC in air atmosphere ( Fig. 2). TGA curve shows three well-defined steps. The first two steps (weight loss of ~13%) start at room temperature and finish at approximately 120°C. These are attributed to water desorption. From 275 to 325°C,there is a rapid weight loss (of ~53%), accompanied by a strong exothermic peak with maximum at 305°C, which was be attributed to the decomposition of cerium acetylacetonate into oxides; and finally, decomposition of Ce(acac)4 is completed at 342°C.

Ce(acac)4 for CeO2 films by spray pyrolysis

Ce(acac)4 has been applied as cerium precursor for the deposition of smooth homogeneous CeO2 films by ultrasonic spray pyrolysis. The precursor dissolved in anhydrous methanol (at concentration 0.025 M) was sprayed on the substrates at heating plate temperature 325°C to 600°C, using carrier gas flow rate 1.5 slm and oxidation gas (air) varied between 1 and 3.5 slm. In the optimized conditions, nanostructured films with particles sizes <10 nm were grown, with growth rate about 2.2 µm/h. Film conductivity increased and activation energy reduced with the reduction of porosity and nanoparticles size (very important in low-temperature electrochemical devices based on CeO2). [[i]]

[i] Synthesis and Characterization of Nanostructured Cerium Dioxide Thin Films Deposited by Ultrasonic Spray Pyrolysis

Mario F. García-Sánchez, Armando Ortiz, Guillermo Santana, Monserrat Bizarro, Juan Peña, Francisco Cruz-Gandarilla, Miguel A. Aguilar-Frutis, Juan C. Alonso, J. Am. Ceram. Soc., 93 [1] 155–160 (2010), DOI: 10.1111/j.1551-2916.2009.03374.x

https://www.researchgate.net/profile/Monserrat_Bizarro/publication/227790783_Synthesis_and_Characterization_of_Nanostructured_Cerium_Dioxide_Thin_Films_Deposited_by_Ultrasonic_Spray_Pyrolysis/links/55843cd508aeb0cdaddbb448.pdf

Cerium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) phenantroline adduct Ce(thd)3(phen)

Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cerium phenantroline adduct Ce(thd)3(phen)

Ce(thd)3 (phen), in combination with ozone O3 as oxidant, has been applied as Ce precursor for the ALD growth of polycrystalline CeO2 layers on soda lime glass and Si(100) at 225-275°C; the growth results were compared with growth of layers using Ce(thd)4 precursor at 175-250°C. Thickness, crystallinity and morphology of the CeO2 films were studied by UV-VIS spectroscopic, XRD and AFM measurements, respectively. The growth rate of CeO2 inside the ALD window was 0.42 Å/cycle for Ce(thd)3 (phen), higher than 0.32 Å/cycle with Ce(thd)4. According to TOF-ERD analysis, the films were nearly stoichiometric (O:Ce ratio ~2the films contained hydrogen (7–10 at.%), as well as some C and F as impurities. [[i] ]

[i]Jani Päiväsaari Matti Putkonena , Lauri Niinistö

J. Mater. Chem., 2002,12, 1828-1832; DOI: 10.1039/B108333C

Cerium tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionate) Ce(thd)4

Cerium tetramethylheptanedionate Ce(thd)4 is popular precursor for the MOCVD and ALD growth of cerium-containing layers (such as CeO2), due to its high volatility and stability.

High purity Ce(DPM)4 (DPM = dipivaloylmethanate = 2,2,6,6-tetramethyl-3,5-heptanedionate) was successfully synthesized from inorganic salts and HDPM in ethanol/aqueous solution, purified by recrystallization from toluene and characterized by elemental analysis, XRD, TGA/DTA, NMR and FTIR spectroscopy (both fresh and aged for 30 days in air), Ce(DPM)4 was applied as precursor of MOCVD of Ce-containing multi-component oxide thin films. [[i]]

[i]H. Song, Y. Jiang, Ch. Xia, G. Meng, D. Peng, https://doi.org/10.1016/S0022-0248(02)02413-2, https://www.sciencedirect.com/science/article/pii/S0022024802024132

“Synthesis and characterization of volatile metal β-diketonate chelates of M(DPM)n (M=Ce, Gd, Y, Zr, n=3,4) used as precursors for MOCVD”

Ce(thd)4 for CeO2 films by solid source MOCVD

Cerium tetramethylheptanedionated Ce(thd)4 has been applied as Ce precursor for the solid-source MOCVD growth of highly textured CeO2 films on (11̄02)-oriented Al203 (r-plane sapphire) substrates. Higher growth temperature and higher deposition rates favored (111) orientation. Epitaxial (100) CeO2 films of 15nm thickness had very smooth surfaces with an RMS surface roughness 0.7nm, as measured by AFM. [[i]]

[i] Solid source MOCVD for the epitaxial growth of thin oxide films

Z. Lu, R.S. Feigelson, R.K. Route, S.A. DiCarolis, R. Hiskes and R.D. Jacowitz

Journal of Crystal Growth, Volume 128, Issues 1-4, Part 2, 1 March 1993, Pages 788-792

Crystal Growth 1992, Proceedings of the Tenth International Conference on Crystal Growth

Ce(thd)4 for Ce-doped SrS films by ALE and CVD

Tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)cerium Ce(thd)4 (Ce(tmhd)4) has been tested as precursor for the preparation Ce-doped strontium sulfide (SrS:Ce) thin films by ALE and CVD for thin-film electroluminescent display applications. [626]

Cerium (IV) tetrakis(6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedionato)cerium Ce(fdh)4

Cerium (III) tris(6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedionato)cerium phenantroline adduct Ce(fdh)3(phen)

Cerium (IV) tetrakis(trifluorodimethylhexanedionato) Ce(fdh)4, and phenatronine adduct of cerium (III) tris (6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedionato) Ce(fdh)3(phen), have been sysnthesized and characterized by mass spectrometry, IR spectroscopy and thermal analysis (TGA/DTA). The complexes are non-hygroscopic, air-stable solids. Ce(fdh)4, Ce(fdh)3(phen), and Na[Ce(fdh)4] are thermally stable and can be sublimed, The crystal structure of Ce(fdh)4 was determined. [[i]

Ce(fdh)4 and Ce(fdh)3(phen)were applied as precursors for the deposition of thin CeO2 layers in horizontal MOCVD reactor. As determined by XRD, single phase CeO2 films with highly preferential (100) or (111) orientation have been prepared, depending on the growth conditions; the growth rate was determined by ellipsometry and profilometry. The dependence of layer properties on evaporation rate, O2 flow and growth temperature was studied. [[ii]]

[i] M. Becht, K.-H. Dahmen, V. Gramlich, A. Marteletti, Inorganica Chimica Acta, Vol.248, Iss.1, 1996, p. 27–33, http://www.sciencedirect.com/science/article/pii/0020169395049894

“Crystal structure and thermal behavior of some cerium complexes with the fluorinated β-diketonate ligand 6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedione (fdh)”

[ii] Michael Becht , Tobias Gerfin , Klaus Hermann Dahmen

Chem. Mater., 1993, 5 (1), pp 137–144, DOI: 10.1021/cm00025a026 ,

"Some cerium .beta.-diketonate derivatives as MOCVD precursors”

http://pubs.acs.org/doi/abs/10.1021/cm00025a026#

http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/1993/cmatex.1993.5.issue-1/cm00025a026/production/cm00025a026.fp.png_v03

Cerium tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-3,5-dionate) Ce(fod)3

Cerium (III) heptafluorodimethyloctanedionate Ce(fod)3 has been applied as precursor for the deposition of CeO2 layers by aerosol MOCVD on (1-102) sapphire at temperatures 500-900°C (films grown on Si substrates were polycrystalline). Typical growth conditions: precursor concentration 0.01 M (in diglyme solvent), optimal delivery rate 0.4ml/min, growth pressure 10 torr, 600 sccm Ar carrier, 500sccm O2. Best quality CeO2 films were obtained at highest temperature, typical thickness was ~0.2 µm, rocking curve (003) FWHM 0.3°- 0.4°. The epitaxial character of the CeO2 films was confirmed by φ-scan, as well as minimal yield 5.5 % measured by RBS in the channeling mode. The grown CeO2 films were successfully applied as buffer layer for the growth of high-Tc superconducting YBaCuO layers. [[i]]

[i] K. Fröhlich, J. Souc, D. Machajdík, A.P. Kobzev, F. Weiss, J.P. Senateur, K.H. Dahmen

J. Phys. IV France 05 (1995) C5-533-C5-540, DOI: 10.1051/jphyscol:1995562

Properties of Thin Epitaxial Aerosol MOCVD CeO2 Films Grown on (1102) Sapphire

http://jp4.journaldephysique.org/articles/jp4/abs/1995/05/jp4199505C562/jp4199505C562.html

https://hal.archives-ouvertes.fr/file/index/docid/253924/filename/ajp-jp4199505C562.pdf

Cerium tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-3,5-dionate) tetraglyme adduct [{Ce(fod)3}2(tetraglyme)]

Cerium tris(heptafluorodimethyloctanedionate) tetraglyme adduct [{Ce(fod)3}2(tetraglyme)], a novel, air-stable, liquid cerium precursor was synthesized and evaluated thermally as potential MOCVD precursor. [{Ce(fod)3}2(tetraglyme)] has been used for the MOCVD growth of good quality, thick, crystalline CeO2 thin films. [[i]]

[i] J.McAleese, Jawwad A. Darr, Brian C. H. Steele, Chemical Vapor Deposition, Volume 2, Issue 6, pages 244–247, November 1996, DOI: 10.1002/cvde.19960020607 , “The synthesis and thermal evaluation of a novel cerium precursor to grow thick ceria films by metal-organic chemical vapor deposition (MOCVD)”

Cerium tetrakis(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-3,5-dionate) Ce(fod)4

Cerium tetrakis(heptafluorodimethyloctanedionate) Ce(fod)4 has been tested as MOCVD precursor for the growth of CeO2 films. The composition of the deposited films was analysed by XPS, the residual fluorine was present in the form of fluoride, as well as organo-related fluorine species that converted rapidly to fluoride during XPS measurement. The XPS spectrum of CeO2 developed the presence of Ce3+, with rate of conversion being sample dependent. [[i] ]

[i] D. Chadwick, J. McAleese, K. Senkiw, B.C.H. Steele, Applied Surface Science, Volume 99, Issue 4, 1 August 1996, Pages 417–420, “On the application of XPS to ceria films grown by MOCVD using a fluorinated precursor”

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