Electron beams can acquire designed phase modulations by passing through nanostructured material phase plates. These phase modulations enable electron wavefront shaping and benefit electron microscopy, spectroscopy, lithography, and interferometry. However, in the fabrication of electron phase plates, the typically used focused-ion-beam-milling method limits the fabrication throughput and hence the active area of the phase plates. Here, we fabricated large-area electron phase plates with electron-beam lithography and reactive-ion-etching. The phase plates are characterized by electron diffraction in transmission electron microscopes with various electron energies, as well as diffractive imaging in a scanning electron microscope. We found the phase plates could produce a null in the center of the bright-field based on coherent interference of diffractive beams. Our work adds capabilities to the fabrication of electron phase plates. The nullification of the direct beam and the tunable diffraction efficiency demonstrated here also paves the way towards novel dark-field electron-microscopy techniques.

中文翻译：

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纳米结构膜电子相位板

电子束可以通过穿过纳米结构材料相位板来获得设计的相位调制。这些相位调制使电子波前成形并有益于电子显微镜、光谱学、光刻和干涉测量。然而，在电子相位板的制造中，通常使用的聚焦离子束铣削方法限制了制造产量，从而限制了相位板的有效面积。在这里，我们用电子束光刻和反应离子蚀刻制造了大面积电子相位板。相位板的特征在于具有各种电子能量的透射电子显微镜中的电子衍射，以及扫描电子显微镜中的衍射成像。我们发现相位板可以基于衍射光束的相干干涉在明场中心产生零点。我们的工作增加了制造电子相位板的能力。这里展示的直接光束的无效化和可调衍射效率也为新型暗场电子显微镜技术铺平了道路。