Emmrich Daniel, Wolff Annalena, Meyerbröker Nikolaus, Lindner Jörg K N, Beyer André, Gölzhäuser Armin
Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany.
Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane 4000, QLD, Australia.
Beilstein J Nanotechnol. 2021 Feb 26;12:222-231. doi: 10.3762/bjnano.12.18. eCollection 2021.
A dark-field scanning transmission ion microscopy detector was designed for the helium ion microscope. The detection principle is based on a secondary electron conversion holder with an exchangeable aperture strip allowing its acceptance angle to be tuned from 3 to 98 mrad. The contrast mechanism and performance were investigated using freestanding nanometer-thin carbon membranes. The results demonstrate that the detector can be optimized either for most efficient signal collection or for maximum image contrast. The designed setup allows for the imaging of thin low-density materials that otherwise provide little signal or contrast and for a clear end-point detection in the fabrication of nanopores. In addition, the detector is able to determine the thickness of membranes with sub-nanometer precision by quantitatively evaluating the image signal and comparing the results with Monte Carlo simulations. The thickness determined by the dark-field transmission detector is compared to X-ray photoelectron spectroscopy and energy-filtered transmission electron microscopy measurements.
为氦离子显微镜设计了一种暗场扫描透射离子显微镜探测器。其检测原理基于一个带有可更换孔径条的二次电子转换支架，该支架允许其接收角在3至98毫弧度之间调节。使用独立的纳米级薄碳膜研究了其对比度机制和性能。结果表明，该探测器可以针对最有效的信号收集或最大的图像对比度进行优化。所设计的装置能够对薄的低密度材料进行成像，否则这些材料提供的信号或对比度很小，并且能够在纳米孔制造过程中进行清晰的终点检测。此外，该探测器能够通过定量评估图像信号并将结果与蒙特卡罗模拟进行比较，以亚纳米精度确定膜的厚度。将暗场透射探测器确定的厚度与X射线光电子能谱和能量过滤透射电子显微镜测量结果进行了比较。
