Mapping the Origins of Luminescence in ZnO Nanowires by STEM-CL
Mapping the Origins of Luminescence in ZnO Nanowires by STEM-CL
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DOI：
10.1021/acs.jpclett.8b03286
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发表时间：
2019-02-07
影响因子：
5.7
通讯作者：
Shaffer, Milo S. P.
中科院分区：
文献类型：
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作者：
Kennedy, Oscar W.;White, Edward R.;Shaffer, Milo S. P.
在半导体纳米线中，理解发光的来源（激子复合、缺陷等）并且发光中心的分布（它们均匀分布，或集中在结构缺陷处或表面处）对于合成和应用是重要的。我们开发的扫描透射电子显微镜阴极发光（STEM-CL）测量，使单个ZnO纳米线的结构和阴极发光（CL），以高分辨率映射。使用CL像素分辨率为10 nm，CL光谱在这样的纳米线在垂直于纳米线生长轴的方向上的变化被确定为第一次。通过比较局部CL光谱与体光致发光谱，CL光谱特征被分配到内部和表面缺陷结构。高光谱CL地图去卷积，使特征光谱特征与单纳米线内的结构特征在空间上相关。我们已经使用这些地图显示，这些缺陷的空间分布相关的区域，显示出增加的非辐射跃迁率。
In semiconductor nanowires, understanding both the sources of luminescence (excitonic recombination, defects, etc.) and the distribution of luminescent centers (be they uniformly distributed, or concentrated at structural defects or at the surface) is important for synthesis and applications. We develop scanning transmission electron microscopy cathodoluminescence (STEM-CL) measurements, allowing the structure and cathodoluminescence (CL) of single ZnO nanowires to be mapped at high resolution. Using a CL pixel resolution of 10 nm, variations of the CL spectra within such nanowires in the direction perpendicular to the nanowire growth axis are identified for the first time. By comparing the local CL spectra with the bulk photoluminescence spectra, the CL spectral features are assigned to internal and surface defect structures. Hyperspectral CL maps are deconvolved to enable characteristic spectral features to be spatially correlated with structural features within single nanowires. We have used these maps to show that the spatial distribution of these defects correlates well with regions that show an increased rate of nonradiative transitions.