Hashimoto Ayako, Mitsuishi Kazutaka, Shimojo Masayuki, Zhu Yufang, Takeguchi Masaki
Advanced Nano-characterization Center, National Institute for Materials Science, 3-13 Sakura, Tsukuba, Japan.
J Electron Microsc (Tokyo). 2011;60(3):227-34. doi: 10.1093/jmicro/dfr013. Epub 2011 Apr 12.
We experimentally examined the characteristics of bright-field (BF) scanning confocal electron microscopy (SCEM) images by changing the observation conditions and comparing the images with those obtained by BF transmission electron microscopy (TEM) and BF scanning TEM (STEM) modes. The observation of 5-nm-diameter Au nanoparticles demonstrated that BF-SCEM produces object elongation of more than 2000 nm along the optical axis, as do BF-TEM and BF-STEM. We demonstrated the relationship between elongation length and geometric effects such as convergence and collection angles of a probe and the lateral size of an object; the relationship is consistent with previous theoretical prediction. Further, we observed interesting features that are seen only in the BF-SCEM images; the film contrast was strongly enhanced, compared with that of BF-STEM. In addition, a bright contrast appeared around the object position in the elongated images. Using this characteristic, we could determine the object position and structure.
我们通过改变观察条件，并将明场（BF）扫描共聚焦电子显微镜（SCEM）图像与明场透射电子显微镜（TEM）和明场扫描透射电子显微镜（STEM）模式下获得的图像进行比较，对其图像特征进行了实验研究。对直径为5nm的金纳米颗粒的观察表明，与BF-TEM和BF-STEM一样，BF-SCEM会使物体沿光轴伸长超过2000nm。我们证明了伸长长度与诸如探针的会聚角和收集角以及物体横向尺寸等几何效应之间的关系；该关系与先前的理论预测一致。此外，我们观察到了仅在BF-SCEM图像中出现的有趣特征；与BF-STEM相比，薄膜对比度得到了显著增强。此外，在伸长图像中的物体位置周围出现了明亮的对比度。利用这一特性，我们可以确定物体的位置和结构。
