Quantification of Sample Thickness and In-Concentration of InGaAs Quantum Wells by Transmission Measurements in a Scanning Electron Microscope
Quantification of Sample Thickness and In-Concentration of InGaAs Quantum Wells by Transmission Measurements in a Scanning Electron Microscope
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通过扫描电子显微镜中的透射测量来量化 InGaAs 量子阱的样品厚度和浓度不均
DOI：
10.1017/s1431927610000292
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发表时间：
2010
影响因子：
2.8
通讯作者：
D. Gerthsen
中科院分区：
文献类型：
--
作者：
T. Volkenandt;E. Müller;D. Hu;D. Schaadt;D. Gerthsen
电子透明样品的高角度环形暗场（HAADF）扫描透射电子显微镜（STEM）图像显示优势原子序数（Z-）对比度，具有高横向分辨率。本文将低电子能<30 keV的HAADF STEM应用于InGaAs量子阱的定量组成分析。为了确定局部成分，将归一化实验图像强度与蒙特卡罗模拟结果进行了比较。为了验证该技术，使用了已知In浓度的InGaAs/GaAs量子阱结构。利用聚焦离子束技术制备了厚度已知的透射电镜样品。该方法可以扩展到其他材料系统，特别有希望分析对撞击损伤敏感的材料。
Abstract High-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images of electron-transparent samples show dominant atomic number (Z-) contrast with a high lateral resolution. HAADF STEM at low electron energies <30 keV is applied in this work for quantitative composition analyses of InGaAs quantum wells. To determine the local composition, normalized experimental image intensities are compared with results of Monte Carlo simulations. For verification of the technique, InGaAs/GaAs quantum-well structures with known In concentration are used. Transmission electron microscopy samples with known thickness are prepared by the focused-ion-beam technique. The method can be extended to other material systems and is particularly promising for the analysis of materials that are sensitive toward knock-on damage.