Deal Andrew, Hooghan Tejpal, Eades Alwyn
GE Global Research, One Research Circle, Niskayuna, NY 12309, USA.
Ultramicroscopy. 2008 Jan;108(2):116-25. doi: 10.1016/j.ultramic.2007.03.010. Epub 2007 Mar 31.
The electron backscatter diffraction (EBSD) analytical technique is invaluable for determining the crystallography of bulk alloys, thin films, and nanoparticles. However, our physical understanding of EBSD pattern generation is incomplete, which hinders our ability to push the limits of EBSD analysis. Here, using an energy filter with better than 10 eV resolution, we experimentally demonstrate the energy dependence of EBSD patterns from elements over a large atomic number range. We verify that low-loss electrons are the major contributors to EBSD patterns, but that there is still a diffraction contribution from electrons with only 80% of the incident beam energy. Additionally, the bands in filtered EBSD patterns have contrast that is more than twice the contrast of their unfiltered counterparts. The band contrast reaches a maximum for a cutoff energy in the filter of about 3% below the energy of the incident beam. Different mechanisms are used to explain the drop in contrast on each side of the maximum. With the cutoff set very close to the energy of the incident beam, the patterns become more blurred. We used a Monte Carlo simulation in the analysis of these experiments.
电子背散射衍射（EBSD）分析技术对于确定块状合金、薄膜和纳米颗粒的晶体学至关重要。然而，我们对EBSD图案生成的物理理解并不完整，这限制了我们拓展EBSD分析极限的能力。在此，我们使用分辨率优于10 eV的能量过滤器，通过实验证明了在较大原子序数范围内元素的EBSD图案的能量依赖性。我们证实低损失电子是EBSD图案的主要贡献者，但能量仅为入射束能量80%的电子仍有衍射贡献。此外，滤波后的EBSD图案中的条带对比度是未滤波对应图案对比度的两倍多。当过滤器中的截止能量比入射束能量低约3%时，条带对比度达到最大值。我们使用不同的机制来解释最大值两侧对比度下降的情况。当截止能量设置得非常接近入射束能量时，图案会变得更加模糊。我们在这些实验的分析中使用了蒙特卡罗模拟。
