Nonlinear inelastic electron scattering revealed by plasmon-enhanced electron energy-loss spectroscopy
Nonlinear inelastic electron scattering revealed by plasmon-enhanced electron energy-loss spectroscopy
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DOI：
10.1038/nphys3051
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发表时间：
2014-08
期刊：
影响因子：
19.6
通讯作者：
Chunyi Xu;Wen-Jie Liu;Panke Zhang;Meng Li;Hanhong Zhang;Ke Xu;Yi Luo;X. Chen
中科院分区：
文献类型：
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作者：
Chunyi Xu;Wen-Jie Liu;Panke Zhang;Meng Li;Hanhong Zhang;Ke Xu;Yi Luo;X. Chen
电子能量损失谱是鉴定材料、的化学成分的有力工具。它主要依赖于非弹性电子的测量，非弹性电子携带特定的原子或分子信息。然而，非弹性电子散射的强度非常低，通常比弹性散射电子的强度弱几个数量级。在这里，我们观察到银纳米结构的增强非弹性电子散射，其强度可以达到其弹性对应结构的60%。利用自制的扫描探针电子能量损失谱仪产生了高度局域的等离子体激元激发，显著提高了银纳米结构的局域电场强度。非弹性电子散射的强度相对于针尖-样品偏置产生的电场呈非线性增加，这为非线性电子散射过程提供了直接证据。
Electron energy-loss spectroscopy is a powerful tool for identifying the chemical composition of materials,,,,. It relies mostly on the measurement of inelastic electrons, which carry specific atomic or molecular information. Inelastic electron scattering, however, has a very low intensity, often orders of magnitude weaker than that of elastically scattered electrons. Here, we report the observation of enhanced inelastic electron scattering from silver nanostructures, the intensity of which can reach up to 60% of its elastic counterpart. A home-made scanning probe electron energy-loss spectrometer was used to produce highly localized plasmonic excitations, significantly enhancing the strength of the local electric field of silver nanostructures. The intensity of inelastic electron scattering was found to increase nonlinearly with respect to the electric field generated by the tip–sample bias, providing direct evidence of nonlinear electron scattering processes.