Ion Dynamics at Interfaces on Nano-structured Ion Conducting Artificial Lattices

高温能量转换系统，如固体氧化物燃料电池（SOFC）等，具有很大的潜力成为高效率的能源系统。然而，在广泛的应用领域中，实际应用还存在一些问题。本研究通过制造人工超晶格结构来控制固态电解质材料的界面特性。此外，还利用开尔文探针力显微镜研究了导电材料陶瓷的界面，以明确晶界性质与电导率之间的关系。得到以下结果：(1)以有序阳极多孔氧化铝膜为光刻掩膜，采用SF_6快速原子束刻蚀法制备了钙钛矿型质子导电纳米薄膜。在MgO（110）衬底上激光烧蚀沉积的SrCeO_3薄膜上绘出了周期为100和500 nm的六边形结构。x射线衍射分析发现，垂直于衬底表面的晶格常数a随着纳米结构周期性的减小而减小。透射光谱和反射光谱显示出表面浮雕光栅结构的典型特征。(2)在不与样品接触的情况下，利用开尔文探针力显微镜对被认为是SOFC阳极材料的nb掺杂SrTiO_3的单个晶界表面电位进行了评价。系统地研究了表面电位与晶界特性的关系，发现随机晶界的表面电位与其他增益边界类型有很大的不同。

High temperature energy conversion systems for example solid oxide fuel cells (SOFC) etc have great potentials for high efficiency energy systems. However, there are several points of problems for practical application in wide application fields. In this study, the interface properties of solid state electrolyte materials is controlled by fabricating the artificial superlattice structures. Furthermore, the interface of ceramics of electrical conducting materials is also investigated by Kelvin probe force microscopy, in order to clear the relationship between the grain boundary natures and electrical conductivity. The following results are obtained;(1) Nano-structured perovskite-type proton conducting thin films have been fabricated by SF_6 fast atom beam etching, with an ordered anodic porous alumina membrane as a lithographic mask. 100 and 500 nm period hexagonal structures are patterned on laser ablation deposited SrCeO_3 film on MgO (110) substrate. It is found from x-ray diffraction analysis that the lattice constant a, which is perpendicular to the substrate surface, decreases with decreasing periodicity of the nano-structure. The optical transmission and reflection spectra show typical features of surface-relief grating structures.(2) Surface potential of individual grain boundaries of Nb-doped SrTiO_3 which has been considered a candidate of anode material of SOFC are evaluated by Kelvin probe force microscopy, without contacting to sample. Systematically investigation of the relationship between surface potential and grain boundary character, it is found that the surface potential at random boundary is quite different from other gain boundary types.