【作者】 张进兵；

【导师】 张志勇；

【作者基本信息】 西北大学 ， 物理电子学， 2011， 硕士

【摘要】 Sr2TiO4是一种二维层状钙钛矿型宽禁带氧化物,因其优异的光电特性将成为可替代二元氧化物薄膜的三元化合物材料。原材料廉价且地球储量丰富,室温下禁带宽度约为3.8eV,在可见光波段透明。本征Sr2TiO4为绝缘体,适当掺杂之后,可变为良好的半导体和导体,可用于宽禁带透明半导体和透明导电领域,如电致发光器件、太阳能电池、电阻开关存储器等。特别是利用Sr2TiO4作为薄膜晶体管的半导体层,由于其兼具可控电传导与可见光波段透明,这在很大程度上拓宽了透明薄膜晶体管的应用领域,因此,能够得到优质的透明导电薄膜是实现其不寻常特性的关键。采用溶胶凝胶工艺制备一系列Sr2TiO4粉体和透明导电薄膜,用X射线衍射、扫描电子显微镜、原子力显微镜对材料的物相和表面形貌进行了观察和分析。用薄膜光学测试仪NKD-8000、四探针测试仪对薄膜进行了光、电性能测试,讨论了PVP的添加量及施主掺杂浓度对薄膜光电特性的影响。使用正交设计方法优化出制备粉体材料的工艺参数,分析了水量、酸量、热处理温度对材料形成的影响,发现在水锶比为38：1,水酸比为1.5：1,退火温度为850℃情况下所得到的材料结构较好。溶胶-凝胶旋涂法制备的Sr2TiO4薄膜表面形貌、光学性能的研究表明,添加摩尔比0.4%的PVP能显著改善薄膜的表面形貌及光特性。La元素的掺入能改善薄膜的形貌及光电特性。更多还原

【Abstract】 Sr2TiO4material is a kind of two-dimensional layered perovskite oxide with large energy gap, it will be an alternative of the dualistic oxide materials as a ternary compound materials for its excellent photoelectric characteristics, It can be prepared from raw materials which are cheap and abundant on the earth, its energy gap is about 3.8 eV at room temperature, it is transparent to the visible light band. Intrinsic Sr2TiO4 material is insulated, it turns into semiconductor or conductor with appropriate doping. Thus, it can be used in the field of transparent and conductive semiconductor with large energy gap, such as the electroluminescent devices and solar cells, resistance switch memories etc. Especially, Sr2TiO4 material can be used as semiconductive layer of thin film transistor for its controllable electric conduction and visible light transparency; all of these widen the application fields of transparent thin-film transistors largely. Therefore, how to get high quality transparent conductive film is the key to realize its unusual features.This paper uses the sol-gel method to prepare kinds of Sr2TiO4 powders and transparent conductive thin films. Used X-ray diffraction, scanning electron microscope, atomic force microscope to observe and analyze the surface morphology of the material. Chose the film optical tester NKD8000 and the four-point probe tester to test the photoelectric characteristics of the thin films. The influences to photoelectric characteristics of the films after adding PVP and doping the benefactor impurities are also discussed.Tried orthogonal design method to optimize the process parameters of powder materials, analyzed the influences of forming the material by changing the usage amount of water, acid and the heat treatment temperature. It shows the material has better structure in the experiments when the ratio of water to strontium is 1.5:1(mole ratio) and to acid is 38:1 (volume ratio), annealing temperature is at 850℃.After studying the photoelectric characteristics of Sr2TiO4 thin films prepared by using the sol-gel method, the result suggests a significant improvement of surface topography and optical properties when adding PVP at the ratio of 0.4% mole to strontium. The study also shows that the doping of La can improve the surface morphology and photoelectric characteristics of the Sr2TiO4 thin films.更多还原