AI 中文总结
研究纳米压痕WSe₂中应变和撕裂对单光子发射的作用，通过特殊工艺研究其结构，明确应变松弛情况，发现应变增加使发射体空间密度降低，为利用应变设计二维半导体量子光源提供结构-性能关系见解。
AI 中文摘要
二维单层WSe₂中的单光子发射对于按需产生光量子态具有吸引力。负责单光子产生的电子态优先在局部拉伸应变区域形成，实现确定性定位和应变工程。单层WSe₂的纳米压痕产生可控且可重复的变形，以激活单光子发射态所需的局部应变。然而，使用纳米压痕研究结构-性能关系和制造基于WSe₂的量子光源受到关于压痕二维材料的结构完整性、产生的应变以及发射体亚微米位置等关键问题的阻碍。在这项工作中，我们使用一种制造工艺研究压痕单层WSe₂的结构，该工艺将压痕倒置成可通过电子显微镜探测的突出柱体。我们明确识别出由于撕裂导致的压痕单层WSe₂的应变松弛，并确认在这些系统中仍会形成单光子发射态，可能在撕裂的末端。对于确认完整（即未撕裂）的压痕，我们评估应变工程单光子发射体的能力。虽然应变对发射能量或亮度影响不大，但我们发现应变增加会降低发射体的空间密度。这一趋势表明发射体形成需要最佳应变，且发射体优先在压痕周边形成。我们的研究深入了解了利用应变在单层WSe₂和其他二维半导体中设计量子光源时最相关的结构-性能关系。
英文摘要
Single-photon emission in two-dimensional single-layer WSe2 is attractive for the on-demand generation of quantum states of light. The electronic states that are responsible for single-photon generation preferentially form in regions of localized tensile strain, enabling deterministic positioning and strain engineering. Nanoindentation of single-layer WSe2 yields controlled and reproducible deformations that generate the localized strain needed to activate the single-photon-emitting states. However, using nanoindentation both for investigating structure-property relationships and for manufacturing quantum light sources based on WSe2 is hindered by key questions on the structural integrity of the indented 2D material, the resulting strain generated, and the sub-micron location of the emitters. In this work, we study the structure of indented single-layer WSe2 using a fabrication process that inverts the indents into protruding pillars that can be probed using electron microscopy. We explicitly identify strain relaxation of the indented single-layer WSe2 due to tearing and confirm that single-photon-emitting states still form in these systems, likely at the extremities of the tear. For indents that are confirmed to be intact (i.e., not torn), we assess the ability to strain engineer the single-photon emitters. While strain does not strongly affect the emission energy or the brightness, we find that increased strain reduces the spatial density of emitters. This trend indicates that an optimal amount of strain is needed for emitter formation and/or the emitters preferentially form on the periphery of the indent. Our investigation provides insight into the most relevant structure-property relationships for using strain to engineer quantum light sources in single-layer WSe2 and other 2D semiconductors.
