Nanometric Resolved Luminescence in h-BN Flakes: Excitons and Stacking Order
Nanometric Resolved Luminescence in h-BN Flakes: Excitons and Stacking Order
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DOI：
10.1021/ph500141j
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发表时间：
2014-09-01
期刊：
影响因子：
7
通讯作者：
Zobelli, Alberto
中科院分区：
文献类型：
--
作者：
Bourrellier, Romain;Amato, Michele;Zobelli, Alberto
六方氮化硼 (h-BN) 的强激子发射使得该材料成为远紫外 (UV) 发光器件最有前途的候选材料之一。然而，单激子仅出现在极难合成的完美单晶中，而常规 h-BN 样品则呈现出复杂的发射光谱，并带有几个额外的峰。这些额外排放的微观根源尚不清楚。在这项工作中，我们使用实验和理论方法解决了这个问题，该方法结合了纳米分辨阴极发光、高分辨率透射电子显微镜和最先进的理论光谱方法。我们证明发射光谱在单个几层薄片内是非常不均匀的，并且在结构变形（例如多面平面折叠）时会出现额外的激子，这会导致 h-BN 层堆叠顺序的局部变化。
The strong excitonic emission of hexagonal boron nitride (h-BN) makes this material one of the most promising candidate for light emitting devices in the far ultraviolet (UV). However, single excitons occur only in perfect monocrystals that are extremely hard to synthesize, while regular h-BN samples present a complex emission spectrum with several additional peaks. The microscopic origin of these additional emissions has not yet been understood. In this work we address this problem using an experimental and theoretical approach that combines nanometric resolved cathodoluminescence, high resolution transmission electron microscopy and state of the art theoretical spectroscopy methods. We demonstrate that emission spectra are strongly inhomogeneus within individual few layer flakes and that additional excitons occur at structural deformations, such as faceted plane folds, that lead to local changes of the h-BN layers stacking order.