Lu_2Ti_2O_7薄膜的溶胶凝胶合成及电学特性

Synthesis conditions and electric properties of Lu_2Ti_2O_7 thin films prepared by sol-gel technique

研究了Lu2Ti2O7薄膜的结构、制备和性能.以Si作为基体,采用溶胶凝胶法研究了各种因素：煅烧温度、保温时间、转速和涂层的数量等对薄膜质量包括表面均方根粗糙度等的影响,并在此基础上研究了薄膜的电学性能.研究表明：在650～1 050 ℃能够形成Lu2Ti2O7相,在750 ℃时能够获得Lu2TiO5含量较少的理想薄膜.研究同时表明：温度对表面均方根粗糙度影响相对较大.Lu2Ti2O7薄膜电学性能研究表明：保温时间有利于Lu2Ti2O7的低温相变和Lu2TiO5相的形成,但是对薄膜电学性能的影响相对较小.采用硝酸镥和二氧化钛作为前驱体,通过溶胶凝胶法可以制备致密的Lu2Ti2O7薄膜,该薄膜制备过程中有中间相Lu2 Ti5产生,但该相可通过改变前驱体比例、延长保温时间或者提高煅烧温度来消除.

The structures,fabrication and properties of Lu2Ti2O7 thin films were explored.Depending upon sol-gel fabrication technique,the influence of the spinning parameters,such as annealing temperature,holding time,rotating speed and the number of coating layers on the micro-structure including surface roughness was investigated systematically.Then the electrical properties of the Lu2Ti2O7 films deposited on Si substrates were researched to optimize the parameters for the growth of Lu2Ti2O7 films.The investigation reveals that the annealing temperature no less than 750 ℃ is necessary to obtain an optimal thin film containing less amount of Lu2TiO5,which is formed at temperature arranging from 650 ℃ to 1 050 ℃.Meanwhile,the studies also indicate that the calcination temperature shows a great influence on the surface roughness.Further analysis on electric properties suggests that the holding time is benefit to both the low temperature phase transition of Lu2Ti2O7 and the formation of Lu2TiO5 phase,but it has little effect on the electrical properties of the film.With Lu （NO3）3 and TiO2 as precursors,high densified Lu2Ti2O7 film containing less amounts of Lu2TiO5 phase can be prepared successfully via sol-gel route,and the less amounts of Lu2TiO5 phase can be eliminated by increasing the calcination temperature,prolonging the holding time or adjusting the ratio of Lu（NO3）3 to TiO.