高分辨率电子能量损失谱在材料科学中的应用

Application of high-resolution electron energy-loss spectroscopy in materials science

简要介绍了FEI Titan80-300STEM扫描透射电镜中装配的Wien-filter型能量单色器（monochromator）.文章特别指出,装配有能量单色器的FEI Titan80-300STEM扫描透射电镜,可以直接给出高能量分辨率（~0.1eV）的电子能量损失谱.利用高分辨电子能量损失谱,在高能损失区,对于K或L能级自然宽度（natural width of energylevel）小于0.5eV的元素,可以获得更细致的的近限精细结构（energy-loss near-edge structure）,更有利于解析其电子结构;在低能损失区,可以用于精确地确定半导体材料的带隙（bandgap）以及p型掺杂引起的带隙能的变化.

The Wien-filter type monochromator installed in an FEI Titan 80—300 STEM scanning transmission electron microscope is briefly introduced.It is shown that electron energy-loss spectroscopy（EELS）with an energy resolution better than 0.1 eV can be achieved using the monochromated transmission electron microscope.In the core-loss region,for elements with natural widths of the K-and L-shell energy levels smaller than 0.5 eV,finer near-edge structures can be obtained using the monochromator,and it is also helpful for the understanding of electronic structure.In the low-loss region,high-resolution EELS can be used to determine the bandgaps of semiconductors and the energy shift in the bandgap due to p-type doping.