Mesoscopic electric field predictions and specimen shape measurements to improve reconstruction in atom probe tomography

原子探针层析成像是一种显微镜和微量分析技术，可以以接近原子的精度绘制小体积材料中每种元素的分布。伦敦帝国理工学院（Imperial College London）正在建立一个新的设备，以便在可控的气氛下，将原子探针上的标本轻松转移到透射电子显微镜上，从而对直径小于100纳米的原子探针标本进行精确成像。在复杂器件的分析中，通常是多层堆叠，样品会形成复杂的形状，影响数据重建的空间精度。该项目将建立在与牛津大学合作的基础上，进行中断原子探针实验，通过电子显微镜获得样品形状，并将其输入介观模型，以改进重建方案，并将材料的结构组成和活性与能源应用相关联。我们将这些模型与用于能源应用的材料薄膜上的样品形状的实验测量相结合，在分析的不同阶段通过透射电子显微镜成像。开发的模型没有与CAMECA提供的仪器相连接或嵌入，因此它不会提供CAMECA的竞争优势，因为这主要用于学术用途。

Atom probe tomography is a microscopy and microanalysis technique that can map the distribution of each element in small volume of a material with near-atomic precision. A new facility at Imperial College London is being set up to allow for facile transfer, under controlled atmosphere, of specimens from the atom probe into a transmission electron microscope, allowing for precise imaging of atom probe specimens, which sharp needles below 100 nanometres across. In the analysis of complex devices, typically multilayer stacks, the specimen can develop complex shapes that affect the spatial precision of the data reconstruction. This project will build on a collaboration with the University of Oxford to perform both interrupted atom probe experiments to acquire specimen shapes by electron microscopy and feed these into a mesoscopic model to improve reconstruction protocols, and correlate structure-composition and activity on materials for energy application. We will combine these models with experimental measurements of specimen shape on thin films of materials for energy applications, imaged by transmission-electron microscopy at different stages of the analysis. The developed model is not linked or embedded with the instrument provided by CAMECA, so it will not provide a competitive advance to CAMECA as this is mostly for academic use.