Retrieval of material’s 3D structure using new phase-contrast STEM methods

使用新的相衬 STEM 方法检索材料的 3D 结构

• 批准号: 456681676
• 负责人: Professorin Dr. Ute Kaiser
• 金额: --
• 依托单位: Zentrale Einrichtung Elektronenmikroskopie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2021
• 资助国家: 德国
• 起止时间: 2020-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/456681676?language=en
• 关键词: Retrieval; material; 3D; structure; using

Phase-contrast imaging techniques applied for scanning transmission electron microscope (STEM) not only improve the efficiency of electron dose compared with conventional imaging modes, but also provide more possibilities to investigate nanomaterials. The techniques for phase-contrast imaging were proposed in the 1970s and have been developed in recent years. These phase-contrast imaging techniques are mainly classified in three categories: (a) differential phase contrast (DPC) preferred for investigating dislocations, the magnetic structure, or the electronic structure; (b) differentiated DPC (DDPC) preferred for measuring charge density distribution; (c) integrated DPC (IDPC) method for generating the potential map of the scanned sample surface. Most DPC-based methods cannot produce an isotropic contrast transfer function and are usually applied for investigating thin samples. We find the IDPC method promising and would like to improve the current IDPC mode for thickness-dependent study in this project. Furthermore, based on theoretical studies we plan to retrieve the inner structure of a thick sample from a minimum number of exposures by applying a pixelated detector in STEM. Combining the theoretical work with our dose-dependent study on (S)TEM imaging, we would like to develop an IDPC-based method to acquire the three-dimensional structure of a sample with the minimal input of electron dose and realize it experimentally.

相衬成像技术应用于扫描透射电子显微镜（STEM），与传统成像方式相比，不仅提高了电子剂量效率，而且为研究纳米材料提供了更多可能性。相衬成像技术于20世纪70年代提出，近年来得到了发展。这些相衬成像技术主要分为三类：（a）微分相衬（DPC），优选用于研究位错、磁结构或电子结构;（B）微分DPC（DDPC），优选用于测量电荷密度分布;（c）积分DPC（IDPC）方法，用于生成扫描样品表面的电势图。大多数基于DPC的方法不能产生各向同性的对比度传递函数，并且通常被应用于研究薄样品。我们发现IDPC方法很有前途，并希望在本项目中改进目前的IDPC模式，用于厚度依赖性研究。此外，基于理论研究，我们计划通过在STEM中应用像素化检测器，从最少的曝光次数中检索厚样品的内部结构。结合理论工作和我们对（S）TEM成像的剂量依赖性研究，我们希望开发一种基于IDPC的方法，以最小的电子剂量输入获得样品的三维结构，并在实验上实现它。