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.

与常规成像模式相比，用于扫描透射电子显微镜（STEM）的相对比对象成像技术不仅提高了电子剂量的效率，而且还提供了更多研究纳米材料的可能性。相比成像的技术是在1970年代提出的，近年来已开发。这些相位对比度成像技术主要分为三类：（a）用于研究位错，磁性结构或电子结构的差分相比（DPC）； （b）优选的分化DPC（DDPC）用于测量电荷密度分布； （c）集成的DPC（IDPC）方法，用于生成扫描样品表面的潜在图。大多数基于DPC的方法无法产生各向同性对比转移函数，通常用于研究薄样品。我们发现IDPC方法有希望，并希望改善当前的IDPC模式，以依赖于该项目的厚度依赖性研究。此外，根据理论研究，我们计划通过在茎中应用像素化检测器来从最少的暴露中检索厚样品的内部结构。将理论工作与我们的剂量依赖性研究相结合，我们想开发一种基于IDPC的方法，以获取样品的三维结构，并以电子剂量的最少输入来获取样品的三维结构，并通过实验意识到它。