Functional Metal Oxide Coatings by Molecule-Based Thermal and Plasma Chemical Vapor Deposition Techniques

Abstract

Deposition of thin films through vaccum processes plays an important role in industrial processing of decorative and functional coatings. Many metal oxides have been prepared as thin films using different techniques, however obtaining compositionally uniform phases with a control over grain size and distribution remains an enduring challenge. The difficulties are largely related to complex compositions of functional oxide materials, which makes a control over kinetics of nucleation and growth processes rather difficult to control thus resulting in non-uniform material and inhomogeneous grain size distribution. Application of tailor-made molecular precursors in low pressure or plasma-enhanced chemical vapor deposition (CVD) techniques offers a viable solution for overcoming thermodynamic impediments involved in thin film growth. In this paper molecule-based CVD of functional coatings is demonstrated for iron oxide (Fe2O3, Fe3O4), vanadium oxide (V2O5, VO2) and hafnium oxide (HfO2) phases followed by the characterization of their microstructural, compositional and functional properties which support the advantages of chemical design in simplifying deposition processes and optimizing functional behavior.

Unusual Reactivity of Silicon Grease Towards Metal Alkoxides: Serendipity for Structural Chemistry

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These molecular control of synthesized complexes offer the possibility of single-source precursor fabrication for target ternary and quaternary phase preparation. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Metal alkoxides are versatile precursors for oxide-ceramics largely due to their unique structural diversity, intrinsic propensity towards hydrolysis, presence of preformed strong MÀ O bonds and defined decomposition mechanism. [2,11,12] The preparation of mixedmetallic complexes with pre-defined metal ratio appropriate for the desired materials synthesis (e. g., [MgAl 2 (OR) 8 ] for MgAl 2 O 4 , R=tBu, iPr) [3] is often not a straightforward preparative task, and strongly influenced by different parameters like chosen ligands, reaction temperatures, solvents and combined metals.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Metal alkoxides are versatile precursors for oxide-ceramics largely due to their unique structural diversity, intrinsic propensity towards hydrolysis, presence of preformed strong MÀ O bonds and defined decomposition mechanism. [2,11,12] The preparation of mixedmetallic complexes with pre-defined metal ratio appropriate for the desired materials synthesis (e. g., [MgAl 2 (OR) 8 ] for MgAl 2 O 4 , R=tBu, iPr) [3] is often not a straightforward preparative task, and strongly influenced by different parameters like chosen ligands, reaction temperatures, solvents and combined metals. [2,11,12] In particular, the synthesis of heterotrimetallic alkoxides with structurally characterized compounds limited to [{Cd(OiPr) 3 } M'{M 2 (OiPr) 9 }] 2 (M'=Sr, Ba; M=Ti, Zr, Hf), [21][22][23][24] [{M'(OiPr) 4 (HOiPr)}Ba {M 2 (OiPr) 9 }] (M'=Al, Ga; M=Hf and M'=Al; M=Zr) [25] and [Eu 3 K 3 TiO 2 (OtBu) 11 (OMe/OH)(HOtBu)], [26] is nearly an unexplored field.…”

“…In recent years, enormous efforts have been made in the construction of heterometallic alkoxides, which display the target material composition already at the molecular level [1–20] . These molecular control of synthesized complexes offer the possibility of single‐source precursor fabrication for target ternary and quaternary phase preparation [1–20] . Metal alkoxides are versatile precursors for oxide‐ceramics largely due to their unique structural diversity, intrinsic propensity towards hydrolysis, presence of preformed strong M−O bonds and defined decomposition mechanism [2,11,12] .…”

Fabrication of submicron barium sulfate aggregates in the presence of ethylenediaminetetraacetic acid anions

“…Recently, there has been increasing interest in using barium sulfate particles as reinforcement in polymer matrices (Mann & Ozin, 1996;Mathur, Shen, & Altmayer, 2007). The addition of barium sulfate in polymers can result in materials possessing higher stiffness, strength, and corrosion resistance when compared with that of conventional filled polymer composites (Wang, Wu, Ye, & Zeng, 2003;Zeng & Bai, 2005).…”

Nanostructured ZrO2 membranes prepared by liquid-injection chemical vapor deposition

“…The use of such single molecular sources simplifies the growth procedure significantly and allows a precise control over phase composition and particle size of the films [38][39][40][41][42]. The thermal decomposition of the precursor in liquid-injection MOCVD process was investigated as a function of substrate temperature and injection frequency that allowed tuning the crystalline phase, film thickness and density of the as-deposited zirconia.…”