Local temperature measurement in TEM by parallel beam electron diffraction
Local temperature measurement in TEM by parallel beam electron diffraction
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DOI：
10.1016/j.ultramic.2016.11.028
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发表时间：
2017-05-01
期刊：
影响因子：
2.2
通讯作者：
Spiecker, Erdmann
中科院分区：
文献类型：
--
作者：
Niekiel, Florian;Kraschewski, Simon M.;Spiecker, Erdmann
随着仪器的最新进展推动了原位透射电子显微镜的极限，局部样品温度的问题再次成为焦点。在这项工作中，平行束电子衍射的适用性，局部测量和监测样品的温度在TEM进行评估，在原位加热实验中的应用。将Au纳米颗粒施加到样品表面，通过评估热膨胀时散射角的变化来测量RT至890 ℃范围内的温度。在恒温条件下的重复测量表明，该方法的统计精度高达2.8K。证明了局部测量温度的适用性，映射加热芯片上的温度梯度。由于热膨胀对温度变化的瞬时响应，该方法非常适合于监测甚至快速的温度变化，如淬火实验所示。为了能够进行广泛的原位研究，开发了一种能够以高精度处理大型数据集的评估方法。光束的平行性被确定为关键的实验先决条件，并建立了一个例程，优化光束平行性方面的显微镜对准。除了建立一个程序，局部温度测量，目前的工作证明了独特的能力，MEMS为基础的原位加热设备。
With the recent advances in instrumentation pushing the limits of in situ transmission electron microscopy, the question of local sample temperature comes into focus again. In this work the applicability of parallel beam electron diffraction to locally measure and monitor the sample temperature in TEM is assessed, with applications for in situ heating experiments in mind. With Au nanoparticles applied to the sample surface, temperature is measured in the range from RT to 890 degrees C by evaluating the change in scattering angle upon thermal expansion. Repeated measurements at constant temperature reveal a statistical precision of the method as good as 2.8 K. The applicability to locally measure the temperature is demonstrated mapping the temperature gradient across a heating chip. Owing to instantaneous response of thermal expansion to temperature changes, the method is well suited for monitoring even quick temperature changes, as demonstrated by quenching experiments. In order to enable extensive in situ studies, an evaluation method capable of processing large datasets with high precision is developed. Beam parallelity is identified as crucial experimental prerequisite and a routine is established, optimizing the microscope alignment in terms of beam parallelity. Apart from establishing a procedure for local temperature measurement, the present work demonstrates the unique capabilities of MEMS-based in situ heating equipment.