Perspectives and limitations of symmetric X-ray Bragg reflections for inspecting polytypism in nanowires.
Perspectives and limitations of symmetric X-ray Bragg reflections for inspecting polytypism in nanowires.
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用于检查纳米线多型性的对称 X 射线布拉格反射的视角和局限性。
DOI：
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发表时间：
2016
影响因子：
2.5
通讯作者：
T. Baumbach
中科院分区：
文献类型：
--
作者：
M. Köhl;P. Schroth;T. Baumbach
X射线衍射，可能在生长或退火过程中的时间分辨，是一种重要的技术，在独立的纳米线的多型性的调查。X射线衍射方法的一个主要优点是，与透射电子显微镜相比，它具有很高的统计意义。在这份手稿中，这样的X射线强度分布的解释进行了讨论，并被证明是非平凡的和非唯一的给定测量的[111]c或[333]c反射的多型纳米线生长在（111）c方向。特别地，模拟和比较了纳米线内部多型体的几种统计分布的衍射强度分布。作为一个例子，采用了多型GaAs纳米线，其生长在Si-（111）衬底上，在纤锌矿排列中Ga（或As）平面的面间间距沿（111）c方向比在锌纤锌矿排列中沿着c方向大0.7%。最重要的是，在纳米线中的无缺陷多型体段的长度强烈波动的情况下，高实验相关性的模糊性被证明。作为这些模糊性的结果，从广泛使用的马尔可夫模型的纳米线的堆叠序列的一个大的集合的偏差不能在X射线衍射数据中检测到。因此，这里的结果对于正确解释这些数据具有高度相关性。
X-ray diffraction, possibly time-resolved during growth or annealing, is an important technique for the investigation of polytypism in free-standing nanowires. A major advantage of the X-ray diffraction approach for adequately chosen beam conditions is its high statistical significance in comparison with transmission electron microscopy. In this manuscript the interpretation of such X-ray intensity distribution is discussed, and is shown to be non-trivial and non-unique given measurements of the [111]c or [333]c reflection of polytypic nanowires grown in the (111)c direction. In particular, the diffracted intensity distributions for several statistical distributions of the polytypes inside the nanowires are simulated and compared. As an example, polytypic GaAs nanowires are employed, grown on a Si-(111) substrate with an interplanar spacing of the Ga (or As) planes in the wurtzite arrangement that is 0.7% larger than in the zinc blende arrangement along the (111)c direction. Most importantly, ambiguities of high experimental relevance in the case of strongly fluctuating length of the defect-free polytype segments in the nanowires are demonstrated. As a consequence of these ambiguities, a large set of deviations from the widely used Markov model for the stacking sequences of the nanowires cannot be detected in the X-ray diffraction data. Thus, the results here are of high relevance for the proper interpretation of such data.
影响因子：
6.1
作者：
Rodriguez, Jose A.;Xu, Rui;Miao, Jianwei
通讯作者：
Miao, Jianwei