Karlsruher Institut für Technologie (KIT), Laboratorium für Elektronenmikroskopie (LEM), Engesserstraße 7, D-76131, Karlsruhe, Germany.
Karlsruher Institut für Technologie (KIT), Laboratorium für Elektronenmikroskopie (LEM), Engesserstraße 7, D-76131, Karlsruhe, Germany.
Ultramicroscopy. 2018 Jun;189:39-45. doi: 10.1016/j.ultramic.2018.03.003. Epub 2018 Mar 6.
Thin-film phase plates (PP) have become a valuable tool for the imaging of organic objects in transmission electron microscopy (TEM). The thin film usually consists of amorphous carbon (aC), which undergoes rapid aging under intense illumination with high-energy electrons. The limited lifetime of aC film PPs calls for alternative PP materials with improved material stability. This work presents thin-film PPs fabricated from the metallic glass alloy ZrAlCu (ZAC), which was identified as a promising PP material with beneficial properties, such as a large inelastic mean free path. An adverse effect of the ZAC alloy is the formation of a surface oxide layer in ambient air, which reduces the electrical conductivity and causes electrostatic charging in the electron beam. To avoid surface oxidation, the ZAC alloy is enclosed by thin aC layers. The resulting aC/ZAC/aC layer system is used to fabricate Zernike and Hilbert PPs. Phase-contrast TEM imaging is demonstrated for a sample of carbon nanotubes, which show strong contrast enhancement in PP TEM images.
薄膜位相板（PP）已成为透射电子显微镜（TEM）中有机物体成像的一种有价值的工具。薄膜通常由非晶态碳（aC）组成，在高强度电子束照射下会迅速老化。aC 薄膜 PP 的有限寿命要求使用具有改进的材料稳定性的替代 PP 材料。这项工作展示了由金属玻璃合金 ZrAlCu（ZAC）制成的薄膜 PP，该合金被确定为一种有前途的 PP 材料，具有大的非弹性平均自由程等有益特性。ZAC 合金的一个不利影响是在环境空气中形成表面氧化层，这会降低电导率并在电子束中引起静电充电。为了避免表面氧化，将 ZAC 合金封装在薄的 aC 层中。由此产生的 aC/ZAC/aC 层系统用于制造泽尼克（Zernike）和希尔伯特（Hilbert）位相板。对碳纳米管样品进行了相衬 TEM 成像，结果表明，在 PP TEM 图像中观察到了强烈的对比度增强。
