Self-organized quantum dots in marginally twisted MoSe2/WSe2 and MoS2/WS2 bilayers
Self-organized quantum dots in marginally twisted MoSe2/WSe2 and MoS2/WS2 bilayers
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DOI：
10.1038/s41699-022-00346-0
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发表时间：
2022-10-23
影响因子：
9.7
通讯作者：
Fal'ko, Vladimir, I
中科院分区：
文献类型：
--
作者：
Enaldiev, V. V.;Ferreira, F.;Fal'ko, Vladimir, I
双光子异质结中的莫尔超晶格是材料工程的有力工具。在边缘扭曲(小失准角，theta)的近晶格匹配的二维(2D)晶体莫尔图案的双层膜中，具有公度堆积的磁区的形式，由在NoDW节点处具有应变热点的磁区壁网络(NoDW)隔开。在这里，我们证明了对于第二类过渡金属二卤化物双层膜MoX2/WX2(X=S，Se)，这些热点中的流体静力应变分量为电子和空穴创造了量子点。我们研究了这类物体束缚的电子/空穴态，讨论了它们通过层内带内红外跃迁的表现。电子/空穴的限制，这是最强的theta；lt；0.5度，导致他们的复合线红移产生的单光子发射器(SPE)可广泛调谐约1 eV的失调角度。这些自组织的点可以在具有排列和倒置的MoX2和WX2单元的双层中形成，发射不同极化的光子。我们还发现，应变的热点降低了层内MoX2 A激子的能量，使得量子点态的选择性布居成为可能。
Moire superlattices in twistronic heterostructures are a powerful tool for materials engineering. In marginally twisted (small misalignment angle, theta) bilayers of nearly lattice-matched two-dimensional (2D) crystals moire patterns take the form of domains of commensurate stacking, separated by a network of domain walls (NoDW) with strain hot spots at the NoDW nodes. Here, we show that, for type-II transition metal dichalcogenide bilayers MoX2/WX2 (X=S, Se), the hydrostatic strain component in these hot spots creates quantum dots for electrons and holes. We investigate the electron/hole states bound by such objects, discussing their manifestations via the intralayer intraband infrared transitions. The electron/hole confinement, which is strongest for theta < 0.5 degrees, leads to a red-shift of their recombination line producing single-photon emitters (SPE) broadly tuneable around 1 eV by misalignment angle. These self-organized dots can form in bilayers with both aligned and inverted MoX2 and WX2 unit cells, emitting photons with different polarizations. We also find that the hot spots of strain reduce the intralayer MoX2 A-exciton energy, enabling selective population of the quantum dot states.