Atomic-scale imaging of nanoengineered oxygen vacancy profiles in SrTiO3
Atomic-scale imaging of nanoengineered oxygen vacancy profiles in SrTiO3
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DOI：
10.1038/nature02756
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发表时间：
2004-08-05
期刊：
影响因子：
64.8
通讯作者：
Hwang, HY
中科院分区：
文献类型：
--
作者：
Muller, DA;Nakagawa, N;Hwang, HY
现代氧化物化学的核心是认识到，通过故意偏离理想的化学计量比，可以获得有益的（以及有害的）材料特性（1，2）。相反，控制和限制氧空位的能力对于实现钙钛矿铁电材料、变阻器和场效应器件的全部潜力将是重要的（3，4）。在过渡金属氧化物中，氧空位通常是电子供体，并且在钛酸锶（SrTiO 3）薄膜中，氧空位（与杂质掺杂剂不同）特别重要，因为它们倾向于保持高载流子迁移率，即使在高载流子密度下（5）。在这里，我们报告的成功制造，使用脉冲激光沉积技术，SrTiO 3超晶格薄膜与氧掺杂的档案，表现出亚纳米结晶。我们配置文件的空位浓度在原子尺度上使用环形暗场电子显微镜和核心水平的光谱，并展示绝对检测灵敏度的一至四个氧空位。我们的发现开辟了一条途径，不仅在氧化物中，而且在晶体材料中更普遍地对单个空位及其聚类进行微观研究。
At the heart of modern oxide chemistry lies the recognition that beneficial ( as well as deleterious) materials properties can be obtained by deliberate deviations of oxygen atom occupancy from the ideal stoichiometry(1,2). Conversely, the capability to control and confine oxygen vacancies will be important to realize the full potential of perovskite ferroelectric materials, varistors and field-effect devices(3,4). In transition metal oxides, oxygen vacancies are generally electron donors, and in strontium titanate (SrTiO3) thin films, oxygen vacancies ( unlike impurity dopants) are particularly important because they tend to retain high carrier mobilities, even at high carrier densities(5). Here we report the successful fabrication, using a pulsed laser deposition technique, of SrTiO3 superlattice films with oxygen doping profiles that exhibit subnanometre abruptness. We profile the vacancy concentrations on an atomic scale using annular-dark-field electron microscopy and core-level spectroscopy, and demonstrate absolute detection sensitivities of one to four oxygen vacancies. Our findings open a pathway to the microscopic study of individual vacancies and their clustering, not only in oxides, but in crystalline materials more generally.