Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract We have recently isolated the neo-pentoxide (HOCH2CMe3, ONp) derivatives of Ba, Sr, and Ti as Ba4(ONp)8(HONp)6(py)2, Sr5(O)(ONp)8(Solv)5 (Solv = solvent), and Ti2(ONp)8, respectively. The combination of these precursors were found to be readily soluble in a wide range of solvents and thus were excellent candidates for preparation of barium strontium titanate ((Ba,Sr)TiO3 or BST) thin films using spin-cast deposition techniques. The highest quality BST films for this system were generated from ternary mixtures dissolved in either pyridine or pyridine/toluene. By in situ VT-GIXRD analysis it was determined that the perovskite phase of BST was readily formed at 650°C. The electronic properties of films crystallized at 700°C indicated that the thin films (300 nm) possessed a dielectric constant of 120 (tan δ = 0.03) with a tunability of 29% at ±10 V. 300 nm films (700°C) which had been generated from a standard BST solution modified with a novel tridentate ligand, had a higher dielectric constant of 180 and a tunability of 35% at ±10 V. The collective characteristics of these precursors offer an attractive alternative to the more complex, less stable sol-gel precursors currently in use.
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