传输电子显微镜中的质量厚度测量:用于定量EDS分析的单一标准方法
Thomas J Zega1, Jane Y Howe2, Devin L Schrader3
1Lunar and Planetary Laboratory, Materials Science and Engineering, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, USA.
概括
在扫描传输电子显微镜 (STEM) 中优化X射线分析对于材料科学至关重要. 调整样本持有器的方向可以最大限度地减少X射线遮,从而实现定量组合分析的高精度.
科学领域:
- 材料科学 材料科学 材料科学
- 分析化学 分析化学
- 电子显微镜电子显微镜
背景情况:
- 在扫描传输电子显微镜 (STEM) 中使用能量分散式X射线光谱 (EDS) 的定量组成分析对于材料的表征至关重要.
- 聚焦离子束 (FIB) 制备通常用于创建电子透明样本,但可以引入影响分析的工件.
研究的目的:
- 评估FIB准备的SrTiO3,CaTiO3和Fe硫化物样本的定量EDS分析的单一标准方法.
- 调查和减轻X射线影像对定量EDS准确度的影响.
- 优化分析几何学,以提高STEM-EDS的精度和准确性.
主要方法:
- 使用STEM对SrTiO3,CaTiO3和Fe硫化物的FIB段进行了定量EDS分析.
- 绘制和分析了X射线影像效应.
- 传输电子显微镜中的样本持有器方向被调整以优化对EDS探测器的视线.
- 结果与电子微探针的定量波长分散光谱学 (WDS) 进行了比较.
主要成果:
- 证实X射线的遮蔽是影响定量EDS分析的重要因素.
- 在STEM样本持有器中调整FIB半网格的方向有效地减少了X射线遮蔽.
- 当将STEM-EDS数据与电子微探测器WDS进行比较时,获得了2%的精度.
- 通过优化分析几何学,获得了5%内的精度.
结论:
- 优化的分析几何学,特别是样本持有者的方向,对于STEM中精确的定量EDS分析至关重要.
- 单一标准的方法,当与优化的几何学相结合时,为材料科学应用提供可靠的组成数据.
- 这种方法提供了一种途径,可以在FIB准备的样本中实现高精度,准确的元素定量.
相关概念视频
01:07Scanning Electron Microscopy
4.1K
A scanning electron microscope (SEM) is used to study the surface features of a sample by using an electron beam that scans the sample surface in a two-dimensional manner. Typically, areas between ~1 centimeter to 5 micrometers in width can be imaged. SEM can be used to image bacteria, viruses, tissues as well as larger samples like insects. Conventional SEM gives a magnification ranging from 20X to 30,000X and spatial resolution of 50 to 100 nanometers.
Fundamental Principles
Accelerated...
Fundamental Principles
Accelerated...
4.1K
01:15Transmission Electron Microscopy
5.3K
In 1931, physicist Ernst Ruska—building on the idea that magnetic fields can direct an electron beam just as lenses can direct a beam of light in an optical microscope—developed the first prototype of the electron microscope. This development led to the development of the field of electron microscopy. In the transmission electron microscope (TEM), electrons are produced by a hot tungsten element and accelerated by a potential difference in an electron gun, which gives them up to 400...
5.3K
01:25Overview of Electron Microscopy
8.4K
The wavelengths of visible light ultimately limit the maximum theoretical resolution of images created by light microscopes. Most light microscopes can only magnify 1000X, and a few can magnify up to 1500X. Electrons, like electromagnetic radiation, can behave like waves, but with wavelengths of 0.005 nm, they produce significantly greater resolution up to 0.05 nm as compared to 500 nm for visible light. An electron microscope (EM) can create a sharp image that is magnified up to 2,000,000X.
8.4K
01:07Electron Microscope Tomography and Single-particle Reconstruction
2.3K
Transmission electron microscopy (TEM) can be used to determine the 3D structure of biological samples with the help of techniques such as electron microscope tomography and single-particle reconstruction. While single-particle reconstruction can examine macromolecules and macromolecular complexes in vitro conditions only, tomography permits the study of cell components or small cells in vivo.
Electron Tomography
Electron tomography can be performed either in TEM or STEM (scanning transmission...
Electron Tomography
Electron tomography can be performed either in TEM or STEM (scanning transmission...
2.3K
01:20Preparation of Samples for Electron Microscopy
5.3K
To be visualized by an electron microscope, either transmission or scanning, biological samples need to be fixed (stabilized) so the electron beam does not destroy them and dried thoroughly (desiccated/dehydrated) so the vacuum does not affect them. Fixation needs to be done as quickly as possible because the sample properties will start changing as soon as it is removed from its natural environment. For example, in a tissue sample, the oxygen levels begin decreasing, causing an altered...
5.3K