【作者】 权茂华；

【导师】 赵九蓬；

【作者基本信息】 哈尔滨工业大学 ， 无机化学， 2006， 硕士

【摘要】 采用聚合物前驱体法在Pt/Ti/SiO₂/Si基片上制备了钽酸锂（LiTaO₃）铁电薄膜。以Ta-柠檬酸为原料,替代溶胶-凝胶（Sol-Gel）工艺中金属醇盐,并在水溶液中制备前驱体溶胶,解决了金属醇盐易水解和价格昂贵等问题。以Ta₂O₅为初始原料,以羟基羧酸（柠檬酸）为配位剂与金属离子配位,形成金属-羟基羧酸配合物溶液（Ta-柠檬酸配合物溶液）。以Ta-柠檬酸配合物溶液为原料,乙二醇为酯化剂,采用聚合物前驱体法制备稳定的Li-Ta前驱体溶胶。研究了影响溶胶稳定性的各种因素,通过差热-热重（TG-DTA）测试手段对Li-Ta前驱体溶胶的热分解历程进行了分析。确定了制备稳定Li-Ta前驱体溶胶的最佳工艺,即在pH=7,柠檬酸与乙二醇物质的量比为1∶2,金属离子与柠檬酸物质的量比为1∶8时,可以获得稳定的Li-Ta前驱体溶胶。通过傅立叶红外光谱（FTIR）、Raman光谱和¹³C核磁共振谱（NMR）等测试方法研究了前驱体溶胶形成过程中金属离子的配位情况。提出了一种可能的金属离子与柠檬酸配位的结构式。将稳定的Li-Ta前驱体溶胶旋转镀膜(转速4500r·min^-1,甩胶时间为20s,溶胶粘度13MPa·s),所得湿膜在200℃下干燥,400℃预烧30min,而后经600℃下退火3h。通过扫描电子显微镜（SEM）、原子力显微镜（AFM）、X射线衍射（XRD）研究所得薄膜的表面形貌和相组成。结果表明,热处理过程中未见有其它中间相形成,说明前驱体溶胶各组分混合的均匀性。600℃退火3h所得薄膜为单一晶相的钽酸锂薄膜,薄膜表面均匀、平整、无裂纹。更多还原

【Abstract】 Lithium tantalate （LiTaO₃） ferroelectric thin films were prepared on the Pt/Ti/SiO₂/Si substrates by the polymeric precursor method. Ta-citric acid complex was used as a raw material instead of metal alkoxide in the Sol-Gel method. Precursor sol can be prepared in an aqueous solution, and the problem of using the metal alkoxide such as hydrolyzation, unstable and high price can be solved by using this method.The metal-carboxylate acid complexes were prepared using Ta₂O₅ as raw materials, hydroxyl carboxylic acid such as citric acid as chelating agents. The Li-Ta polymeric gels were prepared using Ta-citric acid complex in an aqueous solution with citric acid （CA） as chelating agent and ethylene glycol （EG） as esterification agent by polymeric precursor method. The research of stability of the precursor sol with different ingredient we have studied. The thermal decomposition of the Li-Ta precursor gels was studied by TG-DTA.Homogeneous Li-Ta precursor solution and gel with no precipitate can be achieved at pH=7 with the molar ratio of metal cations∶CA = 8∶1 and CA∶EG = 1∶2.The chelation between the carboxylic acid and the metal cations was characterized by Fourier transform infrared （FTIR）, Raman spectroscopy and carbon nuclear magnetic resonance spectroscopy (¹³C NMR). A possible molecular structure of the metal cations and citric acid complex was proposed. During the process of preparing the films, the viscosity of the precursor sol was fixed at 13MPa·s, the rotating speed of the spin coating was 4500 r·min-1and the rotating time was 20s. The wet films were dried at 200℃, then were calcined at 400℃for 30min and finally were annealed at 600℃for 3h. The morphology and phase composition of the thin films annealed at different temperatures were characterized by scanning electronic microscope （SEM）、atomic force microscope （AFM） and XRD. The resalts revealed that there was no intermediate phase formed during the heat-treatment process, which indicated that the composition of the precursor sol was homogeneous. By using this method, a更多还原