Transmission Electron Microscopy Analysis Station, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan.
Microscopy (Oxf). 2021 Aug 9;70(4):327-332. doi: 10.1093/jmicro/dfaa076.
Liquid cell transmission electron microscopy (LCTEM) enables imaging of dynamic processes in liquid with high spatial and temporal resolution. The widely used liquid cell (LC) consists of two stacking microchips with a thin wet sample sandwiched between them. The vertically overlapped electron-transparent membrane windows on the microchips provide passage for the electron beam. However, microchips with imprecise dimensions usually cause poor alignment of the windows and difficulty in acquiring high-quality images. In this study, we developed a new and efficient microchip fabrication process for LCTEM with a large viewing area (180 µm × 40 µm) and evaluated the resultant LC. The new positioning reference marks on the surface of the Si wafer dramatically improve the precision of dicing the wafer, making it possible to accurately align the windows on two stacking microchips. The precise alignment led to a liquid thickness of 125.6 nm close to the edge of the viewing area. The performance of our LC was demonstrated by in situ transmission electron microscopy imaging of the dynamic motions of 2-nm Pt particles. This versatile and cost-effective microchip production method can be used to fabricate other types of microchips for in situ electron microscopy.
液相透射电子显微镜（LCTEM）能够以高空间和时间分辨率对液体中的动态过程进行成像。广泛使用的液相细胞（LC）由两个堆叠的微芯片组成，薄的湿样品夹在它们之间。微芯片上垂直重叠的电子透明膜窗为电子束提供了通道。然而，尺寸不精确的微芯片通常会导致窗口对准不良，难以获得高质量的图像。在这项研究中，我们开发了一种用于 LCTEM 的新型高效微芯片制造工艺，具有较大的观察面积（180 µm×40 µm），并对得到的 LC 进行了评估。硅片表面上的新定位参考标记极大地提高了硅片切割的精度，使得可以准确地对准两个堆叠微芯片上的窗口。精确的对准导致液体厚度为 125.6nm，接近观察区域的边缘。通过对 2nmPt 颗粒的动态运动的原位透射电子显微镜成像，证明了我们的 LC 的性能。这种通用且具有成本效益的微芯片制造方法可用于制造其他类型的用于原位电子显微镜的微芯片。
