Deterministic coupling of site-controlled quantum emitters in monolayer WSe2 to plasmonic nanocavities
Deterministic coupling of site-controlled quantum emitters in monolayer WSe2 to plasmonic nanocavities
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DOI：
10.1038/s41565-018-0275-z
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发表时间：
2018-12-01
影响因子：
38.3
通讯作者：
Strauf, Stefan
中科院分区：
文献类型：
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作者：
Luo, Yue;Shepard, Gabriella D.;Strauf, Stefan
固态单量子发射器是片上光子量子技术的关键资源，需要高效的腔-发射器耦合才能实现超越单节点级别的量子网络(1)（,2）。单层WSe2，一种过渡金属二硫化物半导体，可以容纳随机定位的量子发射体（3-6），而纳米气泡(7)以及与过渡金属二硫化物接触的光刻定义的柱阵列充当空间控制的应力源（8,9）。然后，诱导应变可以在指定位置产生激子。这种在二维材料中任意位置产生零维激子的能力，对于可扩展量子技术的发展是有希望的，但到目前为止还缺乏成熟的腔集成，并且受到发射极量子产量低的影响。在这里，我们展示了一种确定性方法，利用金属纳米立方体的尖角在光刻定义的位置实现珀塞尔增强，以增强电场并使二维材料变形。这个纳米等离子体平台可以研究同一个量子发射器在耦合前后的情况。对于3 × 4的量子发射器阵列，我们显示Purcell因子高达551（平均181），单光子发射率高达42 MHz，激子线宽窄至55 μ eV。此外，使用通量生长的WSe2将0D激子寿命提高到高达14ns，并且腔增强的量子产率从初始值1%提高到高达65%（平均44%）。
Solid-state single-quantum emitters are crucial resources for on-chip photonic quantum technologies and require efficient cavity-emitter coupling to realize quantum networks beyond the single-node leve(1)(,2). Monolayer WSe2, a transition metal dichalcogenide semiconductor, can host randomly located quantum emitters(3-6), while nanobubbles(7) as well as lithographically defined arrays of pillars in contact with the transition metal dichalcogenide act as spatially controlled stressors(8,9). The induced strain can then create excitons at defined locations. This ability to create zero-dimensional (0D) excitons anywhere within a 2D material is promising for the development of scalable quantum technologies, but so far lacks mature cavity integration and suffers from low emitter quantum yields. Here we demonstrate a deterministic approach to achieve Purcell enhancement at lithographically defined locations using the sharp corners of a metal nanocube for both electric field enhancement and to deform a 2D material. This nanoplasmonic platform allows the study of the same quantum emitter before and after coupling. For a 3 x 4 array of quantum emitters we show Purcell factors of up to 551 (average of 181), single-photon emission rates of up to 42 MHz and a narrow exciton linewidth as low as 55 mu eV. Furthermore, the use of flux-grown WSe2 increases the 0D exciton lifetimes to up to 14ns and the cavity-enhanced quantum yields from an initial value of 1% to up to 65% (average 44%).