Measuring the absolute position of EELS ionisation edges in a TEM
Measuring the absolute position of EELS ionisation edges in a TEM
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DOI：
10.1016/s0304-3991(03)00185-2
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发表时间：
2004-02-01
期刊：
影响因子：
2.2
通讯作者：
Schryvers, D
中科院分区：
文献类型：
--
作者：
Potapov, PL;Schryvers, D
透射电子显微镜（TEM）中电子能量损失谱（EELS）芯损边绝对位置的测量受到入射电子初始能量不稳定性引起的明显误差的阻碍。这些不稳定性源于连续漂移和随机涟漪的高张力，是不可避免的，在目前这一代的TEM和扫描TEM显微镜。然而，需要更精确的测量，例如，研究不同化合价或化学环境的原子之间的边缘起始的偏移，即所谓的化学位移。这个问题的解决方案是通过收集一系列短期低损失收购紧随其后的核心损失。为了确保在核心损失和低损失收购之间的最小时间间隔，所有操作都必须由计算机控制。积累了一些收购和他们的总和校正的能量漂移允许取消能量不稳定性和相关的核心损失EELS光谱的绝对能量尺度。一个实用的算法，以及必要的校准这样一个过程。此外，使用这一原则收集的光谱和由此产生的测量化学位移在几种金属氧化物的例子。(C)2003 Elsevier B.V.保留所有权利。
Measurements of absolute positions of electron energy loss spectroscopy (EELS) core-loss edges in a transmission electron microscopy (TEM) are hampered by noticeable errors caused by instabilities of the primary energy of the incident electrons. These instabilities originate from a continuous drift and random ripple of the high tension and are unavoidable in the present generation of TEM and scanning TEM microscopes. However, more precise measurements are desired, for instance, to study the shift of the edge onset between atoms of different valency or chemical environment, the so-called chemical shift. A solution to this problem is presented by collecting a series of short low-loss acquisitions immediately followed by core-loss ones. To ensure a minimal time lapse between core-loss and low-loss acquisitions, all operations must be computer controlled. Accumulation of a number of acquisitions and their summation corrected for energy drift allows to cancel the energy instabilities and to relate the core-loss EELS spectra to the absolute energy scale. A practical algorithm is presented as well as the necessary calibrations for such a procedure. Also, examples of spectra collected using this principle and the resulting measured chemical shifts in several metal-oxides are presented. (C) 2003 Elsevier B.V. All rights reserved.