论文标题
使用EDX对原子分辨的HAADF-stumigages进行实验定量
Experimental quantification of atomically-resolved HAADF-STEMimages using EDX
论文作者
论文摘要
通过量化HAADF-STEM中的对比度，可以获得INGAN/GAN多量子井结构中依赖剂组成的原子分辨映射。此处介绍的量化程序不依赖于计算密集型模拟，而是使用EDXMESERUTYS来校准HAADF-STEM对比度。从映射中吸引的im依的直方图为Ingan的生长提供了独特的见解：从Gan到Ingan的过渡，反之亦然，以谨慎的组成增量出现；每个增量都对应于界面的一个单层，这表明成核所需的时间比阶梯的thelentral生长更长。还通过应用峰值对分析来进行应变状态分析，原子柱的位置确定了对比度的定量。应变型估计与从量化的HAADF-STEM获得的估计值非常吻合，尽管精度较低。讨论了可能改进以增加应变映射的精确量，开辟了在原子尺度上定量量子季素合金定量的潜在途径。
Atomically-resolved mappings of the indium composition in InGaN/GaN multi-quantum wellstructures have been obtained by quantifying the contrast in HAADF-STEM. The quantificationprocedure presented here does not rely on computation-intensive simulations, but rather uses EDXmeasurements to calibrate the HAADF-STEM contrast. The histogram of indium compositionsobtained from the mapping provides unique insights into the growth of InGaN: the transitionfrom GaN to InGaN and vice versa occurs in discreet increments of composition; each incrementcorresponds to one monolayer of the interface, indicating that nucleation takes longer than thelateral growth of the step. Strain-state analysis is also performed by applying Peak-Pair Analysisto the positions of the atomic columns identified the quantification of the contrast. The strainmappings yield an estimate of the composition in good agreement with the one obtained fromquantified HAADF-STEM, albeit with a lower precision. Possible improvements to increase theprecision of the strain mappings are discussed, opening potential pathways for the quantification ofarbitrary quaternary alloys at atomic scales.
