Crystallography at the nanoscale: planar defects in ZnO nanospikes
Crystallography at the nanoscale: planar defects in ZnO nanospikes
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DOI：
10.1107/s1600576719009415
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发表时间：
2019-10-01
影响因子：
6.1
通讯作者：
Kienle，Lorenz
中科院分区：
文献类型：
--
作者：
Wolff，Niklas;Hrkac，Viktor;Kienle，Lorenz
在透射电子显微镜内检查各向异性纳米结构，例如线、血小板或尖峰，通常仅在平面图中进行。然而，由于几何原因，诸如生长孪晶界面的固有缺陷有时会被直接观察所掩盖，从而导致叠加。本文介绍了阴影聚焦离子束技术，通过一个程序，可以很容易地扩展到其他各向异性结构，制备多个电子束透明的ZnO纳米钉横截面试样。与相同纳米尖峰的平面图数据相比，这里的观察方向允许在没有叠加的情况下检查缺陷。通过这种方法，观察到纤锌矿型结构内两种孪晶组态共存，即[2 {\overline 1} {\overline 1} 0]^{\rm W}/（0 1 {\overline 1} 1）和[2 {\overline 1} {\overline 1} 0]^{\rm W}/（0 1 {\overline 1} 3），由于区域的叠加，在平面观察期间没有识别出。缺陷排列可能是在火焰传输合成过程中在部分熔融的Zn衬底上形成的晶核的聚结孪晶的结果。三维缺陷模型的孪晶界面结构已被推导出来，并与平面图的调查模拟。
The examination of anisotropic nanostructures, such as wires, platelets or spikes, inside a transmission electron microscope is normally performed only in plan view. However, intrinsic defects such as growth twin interfaces could occasionally be concealed from direct observation for geometric reasons, leading to superposition. This article presents the shadow-focused ion-beam technique to prepare multiple electron-beam-transparent cross-section specimens of ZnO nanospikes, via a procedure which could be readily extended to other anisotropic structures. In contrast with plan-view data of the same nanospikes, here the viewing direction allows the examination of defects without superposition. By this method, the coexistence of two twin configurations inside the wurtzite-type structure is observed, namely [2 {\overline 1} {\overline 1} 0]^{\rm W}/(0 1 {\overline 1} 1) and [2 {\overline 1} {\overline 1} 0]^{\rm W}/(0 1 {\overline 1} 3), which were not identified during the plan-view observations owing to superposition of the domains. The defect arrangement could be the result of coalescence twinning of crystalline nuclei formed on the partially molten Zn substrate during the flame-transport synthesis. Three-dimensional defect models of the twin interface structures have been derived and are correlated with the plan-view investigations by simulation.