Sol-gel-derived Magnesium Oxide Precursor for Thin-film Fabrication

2000 ◽  
Vol 15 (4) ◽  
pp. 842-845 ◽  
Author(s):  
Hyungsoo Choi ◽  
Soontaik Hwang

Magnesium oxide (MgO) precursors were prepared by the sol-gel method using magnesium acetate. The reaction products and intermediates obtained during the sol-gel processing of magnesium acetate under various conditions were analyzed thermally and spectroscopically. No organic groups were detected by infrared spectroscopy after heat treating the reaction products at 400 °C. A large exothermic differential thermal analysis peak below 400 °C demonstrated the oxidation of organic moieties in each product. It was found that the presence of an acid catalyst was crucial during the sol-gel processing of magnesium acetate to produce sols suitable for depositing MgO films. The MgO films fabricated on Si(111) substrates using the precursor sol showed (200) orientation regardless of the presence of surface oxides on the substrates.

1999 ◽  
Vol 30 (1) ◽  
pp. 548 ◽  
Author(s):  
S. H. Woo ◽  
J. J. Kim ◽  
J. H. Ryu ◽  
M. H. Park ◽  
C. W. Park ◽  
...  

2002 ◽  
Vol 54 (2-3) ◽  
pp. 120-123 ◽  
Author(s):  
S Chakrabarti ◽  
D Ganguli ◽  
S Chaudhuri ◽  
A.K Pal

1989 ◽  
Vol 175 ◽  
Author(s):  
M. Spinu ◽  
A. Brennan ◽  
J. Rancourt ◽  
G. L. Wilkes ◽  
J. E. McGrath

AbstractNew organic/inorganic hybrid materials were prepared by hydrolysis and co-condensation of tetramethylorthosilicate (TMOS) with trimethoxysilane functionalized polyimide oligomers via sol-gel ultrastructure processing. In the first reaction step, amine terminated, fully imidized, soluble, high Tg polyimides were prepared from appropriate diamines and dianhydrides by solution imidization techniques. The amine end-groups were then quantitativell derivatized to nadimide structures through reaction with cis-norbornene 2,3 dicarboxylic anhydride. Subsequently, the nadimides were quantitatively derivatized to trimethoxysilane functionalities via hydrosilylation reactions in the presence of chloroplatinic acid catalyst. The resulting hexamethoxy functionalized polyimide oligomers were hydrolyzed and co-condensed at elevated temperatures under mild pressure with TMOS via sol-gel processing to generate thermally stable polyimidesilicate hybrids. The synthesis and characterization of these materials is discussed.


2002 ◽  
Vol 126 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Junying Zhang ◽  
Zhongtai Zhang ◽  
Zilong Tang ◽  
Zishan Zheng ◽  
Yuanhua Lin

2002 ◽  
Vol 17 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
T. Aytug ◽  
B. W. Kang ◽  
P. M. Martin ◽  
...  

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.


2002 ◽  
Vol 96 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Luqian Weng ◽  
Xujin Bao ◽  
Kwesi Sagoe-Crentsil
Keyword(s):  
Sol Gel ◽  

2010 ◽  
Vol 438 ◽  
pp. 65-72 ◽  
Author(s):  
Andreas Mehner ◽  
Ju An Dong ◽  
Timo Hoja ◽  
Torsten Prenzel ◽  
Yildirim Mutlugünes ◽  
...  

The demand for high precision optical elements as micro lens arrays for displays increases continually. Economic mass production of such optical elements is done by replication with high precision optical molds. A new approach for manufacturing such molds was realized by diamond machinable and wear resistant sol-gel coatings. Crack free silica based hybrid coatings from base catalyzed sols from tetraethylorthosilicate (TEOS: Si(OC2H5)4) and methyltriethoxysilane (MTES: Si(CH3)(OC2H5)3) precursors were deposited onto pre-machined steel molds by spin coating process followed by a heat treatment at temperatures up to 800°C. Crack-free multilayer coatings with a total thickness of up to 18 µm were achieved. Micro-machining of these coatings was accomplished by high precision fly cutting with diamond tools. Molds with micro-structured coatings were successfully tested for injection molding of PMMA optical components. The wear resistance of the coatings was successfully tested by injection molding of 1000 PMMA lenses. Hardness and elastic modulus of the coatings were measured by nano indentation. The chemical composition was measured by X-ray photo electron spectroscopy (XPS) as a function of the sol-gel processing parameters.


1991 ◽  
Vol 46 (6) ◽  
pp. 783-788 ◽  
Author(s):  
Christian Egger ◽  
Ulrich Schubert

A heterogenized rhodium complex, prepared by sol-gel processing of Rh(CO)Cl[PPh2CH2CH2Si(OEt)3]2 and Si(OEt)4, is shown to catalyze the conversion of the silanes H4-nSiPh„ (n = 1 - 3) or (HMe2Si)2O to (poly)siloxanes by air or water. Using THF as a solvent, the silanoles Ph3SiOH or Ph2Si(OH)2 are obtained instead. The reaction of phenylacetic acid or acetic acid with HSiPh3 to give silyl esters is catalyzed by the same compound.


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