Single quantum emitters in monolayer semiconductors
Single quantum emitters in monolayer semiconductors
复制标题
单层半导体中的单量子发射器
DOI：
10.1038/nnano.2015.75
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发表时间：
2015-06-01
影响因子：
38.3
通讯作者：
Pan, Jian-Wei
中科院分区：
文献类型：
--
作者：
He, Yu-Ming;Clark, Genevieve;Pan, Jian-Wei
单量子发射器（SQE）是量子光学（1）和光子量子信息技术（2）的核心。迄今为止，所有已证实的固态单光子源都局限于一维（1D;参考文献3）或3D材料（4-7）。在这里，我们报告了一类新的SQE的基础上的激子，在空间上本地化的二维钨二硒化物（WSe 2）单层的缺陷。这些SQE的光发射显示出类似于130 μ eV的窄线宽，比离域谷激子的线宽小大约两个数量级（8）。二阶相关测量揭示了强光子反聚束，这明确地建立了发射的单光子性质（9）。SQE发射显示两个非简并跃迁，它们是交叉线性偏振的。我们将这种精细结构分配给两个激子本征模，其简并度被提升了很大，类似于0.71 meV耦合，可能是因为在各向异性存在下的电子-空穴交换相互作用（10）。磁光测量还揭示了类似于8.7的激子因子，比离域谷激子的激子因子大几倍（11-14）。除了它们的基本重要性之外，在2D量子材料中建立新的SQE可以在量子信息处理中产生实际优势，例如有效的光子提取以及高度的可集成性和可扩展性。
Single quantum emitters (SQEs) are at the heart of quantum optics(1) and photonic quantum-information technologies(2). To date, all the demonstrated solid-state single-photon sources are confined to one-dimensional (1D; ref. 3) or 3D materials(4-7). Here, we report a new class of SQEs based on excitons that are spatially localized by defects in 2D tungsten-diselenide (WSe2) monolayers. The optical emission from these SQEs shows narrow linewidths of similar to 130 mu eV, about two orders of magnitude smaller than those of delocalized valley excitons(8). Second-order correlation measurements revealed a strong photon antibunching, which unambiguously established the single-photon nature of the emission(9). The SQE emission shows two non-degenerate transitions, which are cross-linearly polarized. We assign this fine structure to two excitonic eigen-modes whose degeneracy is lifted by a large similar to 0.71 meV coupling, probably because of the electron-hole exchange interaction in the presence of anisotropy(10). Magneto-optical measurements also reveal an exciton g factor of similar to 8.7, several times larger than those of delocalized valley excitons(11-14). In addition to their fundamental importance, establishing new SQEs in 2D quantum materials could give rise to practical advantages in quantum-information processing, such as an efficient photon extraction and a high integratability and scalability.