Alkoxide Routes to Inorganic Materials

An all alkoxide solution chemistry utilizing metal 2-methoxyethoxide complexes in 2-methoxyethanol was used to deposit thin-films of metal oxides on single-crystal metal oxide substrates and on biaxially textured metal substrates. This same chemistry was used to synthesize complex metal oxide nanoparticles. Nuclear Magnetic Resonance spectroscopy was used to study precursor solutions of the alkaline niobates and tantalates. Film crystallization temperatures were determined from X-ray diffraction patterns of powders derived from the metal oxide precursor solutions. Film structure was determined via X-ray diffraction. Film morphology was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Epitaxial thin-films of strontium bismuth tantalate (SrBi₂Ta₂O₉, SBT) and strontium bismuth niobate (SrBi₂Nb₂O₉, SBN) were deposited on single crystal [1 0 0] magnesium oxide (MgO) buffered with lanthanum manganate (LaMnO₃, LMO). Epitaxial thin films of LMO were deposited on single crystal [100] MgO via Rf-magnetron sputtering and on single crystal [100] lanthanum aluminate (LaAIO₃) via the chemical solution deposition technique.

Epitaxial thin-films of sodium potassium tantalate (Na_0.5K_0.5TaO₃, NKT), sodium potassium niobate (Na_0.5K_0.5NbO₃, NKN) and sodium potassium tantalum niobate (Na_0.5K_0.5Ta_.05Nb_0.5O₃, NKTN) were deposited on single crystal [1 0 0] lanthanum aluminate and [1 0 0] MgO substrates (NKT and NKN) and biaxially textured metal substrates via the chemical solution deposition technique. Epitaxial growth of thin-films of NKT, NKN and NKTN was observed on LAO and Ni-5% W. Epitaxial growth of thin-films of NKN and the growth of c-axis aligned thin-films of NKT was observed on MgO.

Nanoparticles of SBT, SBN, NKT and NKN were synthesized in reverse micelles from alkoxide precursor solutions. X-ray diffraction and transmission electron spectroscopy investigations reveal that amorphous nanoparticles (~5 nm) of SBT and SBN were synthesized. X-ray diffraction investigations reveal that nanoparticles (~3 nm) of NKT and NKN were also synthesized by this method.