Sinclair Robert, Lee Sang Chul, Shi Yezhou, Chueh William C
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
Ultramicroscopy. 2017 Apr;175:25-35. doi: 10.1016/j.ultramic.2016.12.023. Epub 2017 Jan 6.
We have applied aberration-corrected transmission electron microscopy (TEM) imaging and electron energy loss spectroscopy (EELS) to study the structure and chemistry of epitaxial ceria thin films, grown by pulsed laser deposition onto (001) yttria-stabilized zirconia (YSZ) substrates. There are few observable defects apart from the expected mismatch interfacial dislocations and so the films would be expected to have good potential for applications. Under high electron beam dose rate (above about 6000 e/Ås) domains of an ordered structure appear and these are interpreted as being created by oxygen vacancy ordering. The ordered structure does not appear at lower lose rates (ca. 2600 e/Ås) and can be removed by imaging under 1 mbar oxygen gas in an environmental TEM. EELS confirms that there is both oxygen deficiency and the associated increase in Ce versus Ce cations in the ordered domains. In situ high resolution TEM recordings show the formation of the ordered domains as well as atomic migration along the ceria thin film (001) surface.
我们应用了像差校正透射电子显微镜（TEM）成像和电子能量损失谱（EELS）来研究通过脉冲激光沉积生长在（001）钇稳定氧化锆（YSZ）衬底上的外延二氧化铈薄膜的结构和化学性质。除了预期的失配界面位错外，几乎没有可观察到的缺陷，因此预计这些薄膜具有良好的应用潜力。在高电子束剂量率（约6000 e/Ås以上）下，出现了有序结构的畴，这些畴被解释为由氧空位有序化产生。在较低的剂量率（约2600 e/Ås）下，有序结构不会出现，并且可以通过在环境TEM中1 mbar氧气气氛下成像将其去除。EELS证实，在有序畴中存在氧缺陷以及Ce与Ce阳离子相关的增加。原位高分辨率TEM记录显示了有序畴的形成以及沿二氧化铈薄膜（001）表面的原子迁移。
