Propagation of Structural Disorder in Epitaxially Connected Quantum Dot Solids from Atomic to Micron Scale
Propagation of Structural Disorder in Epitaxially Connected Quantum Dot Solids from Atomic to Micron Scale
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DOI：
10.1021/acs.nanolett.6b02382
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发表时间：
2016-09-01
期刊：
影响因子：
10.8
通讯作者：
Kourkoutis, Lena F.
中科院分区：
文献类型：
--
作者：
Savitzky, Benjamin H.;Hovden, Robert;Kourkoutis, Lena F.
自组装胶体量子点的外延连接超晶格为通过跨多个长度尺度的精确分层结构来精确控制电子结构提供了一条有前途的途径。在这里，我们发现无序传播是这些系统的一个基本特征，它与原子、超晶格和晶粒尺度的有序性密切相关。因此，要获得理论上预测的奇异电子态和高度可调的微带，需要详细了解局部结构和远程结构之间的微妙相互作用。为此，我们开发了分析方法，根据真实的副晶体模型定量表征传播无序：并直接观察埃级平移无序对数百纳米结构相关性的巨大影响。使用这个框架，我们发现有序度的提高伴随着样品厚度的增加，并确定了小部分缺失外延键对统计无序的实质性影响。这些结果对于实现远程载波离域和真正的微带形成这一难以捉摸的目标具有重要的实验和理论意义。
Epitaxially connected superlattices of self assembled colloidal quantum dots present a promising route toward exquisite control of electronic structure through precise hierarchical structuring across multiple length scales. Here, we uncover propagation of disorder as an essential feature in these systems, which intimately connects order at the atomic, superlattice, and grain scales. Accessing theoretically predicted exotic electronic states and highly tunable minibands will therefore require detailed understanding of the subtle interplay between local and long-range structure. To that end, we developed analytical methods to quantitatively characterize the propagating disorder in terms of a real paracrystal model :and directly observe the dramatic impact of angstrom scale translational disorder on structural correlations at hundreds of nanometers. Using this framework, we discover improved order accompanies increasing sample thickness and identify the substantial effect of small fractions of missing epitaxial bonds on statistical disorder. These results have significant experimental and theoretical implications for the elusive goals of long-range carrier delocalization and true miniband formation.