FEI Company, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands.
Micron. 2012 Nov;43(11):1156-68. doi: 10.1016/j.micron.2012.01.006. Epub 2012 Jan 30.
An environmental transmission electron microscope provides unique means for the atomic-scale exploration of nanomaterials during the exposure to a reactive gas environment. Here we examine conditions to obtain such in situ observations in the high-resolution transmission electron microscopy (HRTEM) mode with an image resolution of 0.10nm. This HRTEM image resolution threshold is mapped out under different gas conditions, including gas types and pressures, and under different electron optical settings, including electron beam energies, doses and dose-rates. The 0.10nm resolution is retainable for H(2) at 1-10mbar. Even for N(2), the 0.10nm resolution threshold is reached up to at least 10mbar. The optimal imaging conditions are determined by the electron beam energy and the dose-rate as well as an image signal-to-noise (S/N) ratio that is consistent with Rose's criterion of S/N≥5. A discussion on the electron-gas interactions responsible for gas-induced resolution deterioration is given based on interplay with complementary electron diffraction (ED), scanning transmission electron microscopy (STEM) as well as electron energy loss spectroscopy (EELS) data.
环境透射电子显微镜为在反应性气体环境下暴露时对纳米材料进行原子尺度的探索提供了独特的手段。在这里，我们研究了在高分辨率透射电子显微镜（HRTEM）模式下获得这种原位观察的条件，其图像分辨率为 0.10nm。该 HRTEM 图像分辨率阈值在不同的气体条件下进行了映射，包括气体类型和压力，以及不同的电子光学设置，包括电子束能量、剂量和剂量率。在 1-10mbar 的 H(2)下可以保持 0.10nm 的分辨率。即使对于 N(2)，也可以达到至少 10mbar 的 0.10nm 分辨率阈值。最佳成像条件由电子束能量和剂量率以及图像信噪比（S/N）决定，S/N 与 Rose 的 S/N≥5 标准一致。根据与互补电子衍射（ED）、扫描透射电子显微镜（STEM）以及电子能量损失光谱（EELS）数据的相互作用，讨论了导致气体诱导分辨率下降的电子-气体相互作用。
