A model to predict image formation in the three-dimensional field ion microscope
A model to predict image formation in the three-dimensional field ion microscope
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DOI：
10.1016/j.cpc.2020.107317
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
B. Klaes;R. Lardé;F. Delaroche;S. Parviainen;N. Rolland;Shyam Katnagallu;B. Gault;F. Vurpillot
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文献类型：
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作者：
B. Klaes;R. Lardé;F. Delaroche;S. Parviainen;N. Rolland;Shyam Katnagallu;B. Gault;F. Vurpillot
场离子显微镜（Field Ion Microscopy，缩写为AFM）是第一种对材料表面的单个原子进行成像的技术。通过仔细控制表面原子的场蒸发，材料的大部分被暴露，并且通过对一系列显微照片的数字处理，可以实现原子分辨率的三维重建。3D扫描仪特别适合于直接观察构成材料物理特性基础的晶体缺陷：空位和空位簇、位错、位错或晶界。然而，3D打印的进一步发展是必要的，把它变成一个例程技术。在这里，我们首先介绍了一个协议，用于3D图像处理和随后的断层重建。其次，我们提出了一个数值模型，使模拟的成像过程中的电子束。该模型结合了Rolland等人提出的场蒸发的无网格算法（Robin-Rolland模型，或RRM）与场蒸发中涉及的气体图像的场电离过程的基本方面。所提出的模型能够模拟由非规则场蒸发和原子缺陷附近的扰动电场分布引起的成像伪影。我们的模型能够更精确地解释结构缺陷的三维表征。
Field ion microscopy (FIM) was the first technique to image individual atoms on the surface of a material. By a careful control of the field evaporation of surface atoms, the bulk of the material is exposed, and, through digital processing of a sequence of micrographs, an atomically-resolved three-dimensional reconstruction can be achieved. 3DFIM is particularly suited to the direct observation of crystalline defects that underpin the physical properties of materials: vacancies and vacancy clusters, interstitials, dislocations, or grain boundaries. Yet, further developments of 3DFIM are necessary to turn it into a routines technique. Here, we introduce first a protocol for 3DFIM image processing and subsequent tomographic reconstruction. Second, we propose a numerical model enabling simulation of the FIM imaging process. The model combines the meshless algorithm for field evaporation proposed by Rolland et al. (Robin–Rolland Model, or RRM) with fundamental aspects of the field ionization process of the gas image involved in FIM. The proposed model enables the simulation of imaging artefacts that are induced by non-regular field evaporation and by the disturbed electric field distribution near atomic defects. Our model enables more precise interpretation of 3DFIM characterization of structural defects.