化学溶液沉积法在LaAlO_3基底上制备La_(0.5)Sr_(0.5)TiO_3外延薄膜

Preparation of Epitaxial La_(0.5)Sr_(0.5)TiO_3 Thin Films on LaAlO_3 Substrates by Chemical Solution Deposition

在常压下采用经济、适合规模化生产的化学溶液沉积法生长外延的La1-xSrxTiO3薄膜,为YBa2Cu3O7-σ（YBCO）涂层导体提供导电缓冲层。前驱溶液经旋转涂覆在单晶LaAlO3（001）基底上,在纯氩气氛下分别于840,890,940和990℃恒温60 min制备薄膜。X射线衍射（XRD）分析,在890-990℃的热处理条件下,均得到纯净的具有良好外延性的La1-xSrxTiO3薄膜。通过扫描电子显微镜（SEM）和扫描隧道显微镜（STM）观察,样品表面光滑致密,膜厚约为180 nm。通过半定量能谱（EDS）分析,确定薄膜成分为La0.4Sr0.6TiO3,表明热处理过程中元素La部分挥发。在890℃热处理温度下制得薄膜的电阻率约为1×10^-2Ω.cm。

Epitaxial La1-xSrxTiO3 films were prepared by chemical solution deposition under one atmosphere, which was economical and suitable for large-scale production. The films could be used for preparation of buffer layers for YBCO coated conductor. They were prepared on the substrates of single crystal LaAlO3 （100） by means of spin coating, meanwhile they heated at the rate of 15℃.min^-1 to 840, 890, 940 and 990 ℃ respectively and held for 60 min in pure argon of one atmosphere. XRD analysis showed that they were pure La1-xSrxTiO3 epitaxial thin films when heated at 890 ℃ to 990 ℃. The smooth and dense surface of the film was observed by SEM and STM. The thickness of the film was about 180 nm. By EDS analysis, it was confirmed that the films were La0.4 Sr0.6TiO3, and the partial La would volatilize under the heat treatment. The resistivity of the film annealed at 890 ℃ was about 1-10^-2 Ω.cm.