摘 要:
最近,由于BaTiO3/SrTiO3的特殊的物理性质出现了很多关于薄膜的研究。相比较单相的BaTiO3或SrTiO3薄膜而言,BaTiO3/SrTiO3 的超晶格数[1]体现了它们不同的介电性能。特别是,BaTiO3/SrTiO3的超晶格数显示出了一个相当大的介电常数和非光学性质也可以加以阐释薄膜铁电特性的来源。众所周知,这些超晶格的性质和每层薄膜的厚度以及界面的微观结构相关。
但是直到现在为止,除了BaTiO3/SrTiO3的超晶格结构引起了大家的广泛关注外,还应研究薄膜的表面粗糙度、薄膜厚度与薄膜浓度之间的关系。我们用溶胶凝胶法分别在玻璃和Si/SiO2/Ti/Pt衬底上制备了不同浓度的BaTiO3/SrTiO3薄膜,退火温度为750℃。其物理性质通过XRD、AFM、SEM 和反射率测试得到。这些测试结果显示薄膜的峰高、表面粗糙度、薄膜的厚度以及薄膜最小反射率对应的波长都随着BaTiO3/SrTiO3薄膜浓度的升高而上升。
关键词:BaTiO3/SrTiO3薄膜,浓度,峰高,表面粗糙度,厚度,反射率。
Abstract:Recently, a number of studies have been focused on BaTiO3/SrTiO3 thin films because of their remarkable physical properties. BaTiO3/SrTiO3 superlattices show quite different dielectrics properties compared to single-phase films of BaTiO3 or SrTiO3. Particularly, BaTiO3/SrTiO3 superlattices show a dramatically large dielectric constant and large optical nonlinearity which clarify the origin of the remarkable ferroelectricity. It is well known that the properties of these superlattices are very sensitive to the thickness of each layer and the interface microstructures.
Though, up to now, except that BaTiO3/SrTiO3 superlattice structures have been attracted much attention, there are also a few studies reported on the film roughness and thickness which relate to their density. We have prepared different density of BaTiO3/SrTiO3 thin films with multilayered structures deposited on glass and Si/SiO2/Ti/Pt substrates by a sol–gel deposition and heating at 750℃. The physical properties were obtained by XRD, SEM, AFM and reflectivity tests. The results show that the peak height, film roughness, thickness and the wavelength corresponding to the minimum reflectivity are increasing with the rising of the density of BaTiO3/SrTiO3 thin films.
Keywords: BaTiO3/SrTiO3 thin films, density, peak height, roughness, thickness, reflectivity.