• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议> >NANOSCALE STRUCTURE/PROPERTY CORRELATION THROUGH ABERRATION-CORRECTED STEM AND THEORY
【24h】

NANOSCALE STRUCTURE/PROPERTY CORRELATION THROUGH ABERRATION-CORRECTED STEM AND THEORY

机译：通过像差校正的词干与理论的纳米尺度结构/属性相关性

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Aberration correction is enabling smaller, brighter probes to be realized with enormous improvements not only in resolution but also in image contrast and signal to noise ratio. Microscopy will no longer be limited by the instrument but by the sample. In a zone axis crystal, the image resolution will be limited by dynamical diffraction. The fundamental quantum mechanical limit to resolution is set by the 1 s Bloch states, which are typically ～ 0.5 A in width. The Z-contrast image will be a direct image of the 1s Bloch states. Spectacular improvement will also be seen for EELS. Increasing the current down one selected column, and simultaneously decreasing the current illuminating surrounding columns, will improve the analytical sensitivity dramatically. Single impurity atom detection should be possible in specific columns at a grain boundary or dislocation core, and at specific sites on a crystal surface. Figure 12 compares an image of a Pt trimer on a γ-alumina surface obtained with the uncorrected 300 kV STEM to a simulated image for a 0.5 A probe, in which the Pt sites can be seen directly with respect to the different sites in the alumina support. The experimental images of La shown above are beginning to reveal such a level of insight. Spectroscopy at the same spatial resolution will make possible determination of the electronic structure at individual sites surrounding such clusters, individual facets on a catalyst nanocrystal, even around single impurity or dopant atoms. In combination with theory, functionality could be understood at a fundamental level, luminescence efficiency of semiconductor nanocrystals, or how promoter atoms or poisons affect catalytic activity.
机译：像差校正可实现更小，更亮的探头，不仅在分辨率方面，而且在图像对比度和信噪比方面都有巨大的改进。显微镜将不再受仪器的限制，而是受样品的限制。在区域轴晶体中，图像分辨率将受到动态衍射的限制。分辨率的基本量子力学极限是由1 s Bloch状态确定的，该状态的宽度通常约为0.5A。 Z对比图像将是1s Bloch状态的直接图像。 EELS也将获得惊人的改善。在选定的某一列上增加电流，同时在周围的列上照亮的电流将大大提高分析灵敏度。在晶界或位错核的特定列以及晶体表面上的特定位置，应该可以进行单个杂质原子检测。图12将未经校正的300 kV STEM获得的γ-氧化铝表面上的Pt三聚体图像与0.5 A探针的模拟图像进行了比较，其中可以相对于氧化铝中的不同位置直接看到Pt位置支持。上面显示的La的实验图像开始显示出如此高的洞察力。在相同的空间分辨率下进行光谱分析将可能确定围绕此类簇的各个位置，催化剂纳米晶体上的各个小面，甚至单个杂质或掺杂原子周围的电子结构。结合理论，可以从根本上理解功能，半导体纳米晶体的发光效率或促进剂原子或毒物如何影响催化活性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号