12 research outputs found
Niobium and tantalum derivatives with bidentate nitrogen ligands as potential precursors to nitrides
No full textEarly transition metal derivatives with N-donors have attracted interest as precursors of nitrides, the latter being used as diffusion barriers for the ULSI technology. Potential precursors to niobium and tantalum nitrides have been synthesized in good yields and characterized. They are based on bidentate nitrogen donors namely amidinates, benzamidinates and diamido ligands. These have been reacted with niobium or tantalum derivatives namely penta and tetrachlorides, TaCl3(NEt2)2. Disubstituted niobium(IV) and tantalum(V) species such as for instance NbCl2[RNCR'NR2]2 [R= Cy, N(SiMe3)2 ; R = SiMe3, R' = p-tolyl] have been obtained and structurally characterized. The more rigid o-dimethylphenylene diamido ligand lead to a volatile, air stable disubstituted Nb(V) species NbCl(N2(SiMe3)2C6H3}2. However, π-stacking as shown by X-ray studies are responsible of quite low sublimation rates. Thus, volatility could be reached for some species, their properties, high solubility due to the trimethylsilylligands, their stability in solution is more suited for applications in wet MOCVD than conventional one
Chemical vapor deposition (DLI-CVD) and characterization of multiphasic molybdate-based catalysts for propene oxidation
No full textfffInternational audienceliste mot clef
TiO2 anatase films obtained by direct liquid injection atomic layer deposition at low temperature
No full textInternational audienceTiO2 thin films were grown by direct liquid injection atomic layer deposition (DLI-ALD) with infrared rapid thermal heating using titanium tetraisopropoxide and water as precursors. This titanium tetraisopropoxide/water process exhibited a growth rate of 0.018 nm/cycle in a self-limited ALD growth mode at 280 degrees C. Scanning electron microscopy and atomic force microscopy analyses have shown a smooth surface with a low roughness. XPS results demonstrated that the films were pure and close to the TiO2 stoichiometric composition in depth. Raman spectroscopy revealed that the films were crystallized to the anatase structure in the as-deposited state at low temperature without necessity of high temperature annealing. Results obtained demonstrate that the liquid injection ALD is an efficient method of elaborating titanium oxide films using titanium tetraisopropoxide as precursor
Putting Group 13 Elements onto Perylenes: Highly Fluorescent N−B−N- and N−Al−N-substituted Polycyclic Aromatics
No full textSynthesis and Structural Investigation of Tungsten Imido Amidinate and Guanidinate Complexes
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