Strain-Correlated Localized Exciton Energy in Atomically Thin Semiconductors
Strain-Correlated Localized Exciton Energy in Atomically Thin Semiconductors
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DOI：
10.1021/acsphotonics.0c00626
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发表时间：
2020-05-20
期刊：
影响因子：
7
通讯作者：
Englund, Dirk
中科院分区：
文献类型：
--
作者：
Moon, Hyowon;Bersin, Eric;Englund, Dirk
单光子发射器代表了从量子通信到计算的许多量子技术的关键组件。原子级薄的二维材料是量子发射器的有前途的宿主，这要归功于组装适合芯片集成的原子级精确异质结构的巨大自由度。最近的工作表明，稳定的量子发射器可以通过将2D材料放置在衬底中的突起上来确定性地定位。然而，这些发射体的来源及其广泛的光谱分布仍然不清楚。已经提出，由于局部带隙调制和带重新排列，突起附近的微观应变调制起作用，但是局部应变与量子发射体的跃迁能量之间的精确关系仍然难以捉摸。为了解决这个问题，我们研究自由和本地化激子在单层的WSe 2转移到微结构。这些测量结果表明，局域发射能量和应变调制的自由激子能量之间的正相关。此外，它们的能量分离大于42 meV，与最近的理论相一致，该理论表明量子发射体起源于局部应变介导的暗激子态和高度局部化的原子缺陷态的混合。我们的研究结果打开了确定性的定位和光谱控制的量子发射器在二维材料异质结构的潜力。
Single-photon emitters represent a key component for many quantum technologies, from quantum communication to computation. Atomically thin two-dimensional materials are promising hosts of quantum emitters, thanks to great freedom in assembling atomically precise heterostructures that are suitable for chip integration. Recent work showed that stable quantum emitters can be positioned deterministically by placing a 2D material over protrusions in a substrate. However, the origins of these emitters and their broad spectral distribution remain unclear. It has been suggested that the microscopic strain modulation near the protrusions plays a role because of local band gap modulation and band realignment, but the precise relationship between local strain and the transition energy of the quantum emitter remains elusive. To tackle this problem, we study free and localized excitons in a monolayer of WSe2 transferred onto microstructures. These measurements show positive correlation between the localized emission energies and the strain-modulated free-exciton energies. Moreover, their energy separation is larger than 42 meV, in agreement with recent theory suggesting that the quantum emitters originate from local strain-mediated mixing of dark exciton states and highly localized atomic defect states. Our results open the potential for deterministic positioning and spectral control of quantum emitters in 2D material heterostructures.