Ambardar Sharad, Kamh Rana, Withers Zachary H, Sahoo Prasana K, Voronine Dmitri V
Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA.
Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA.
Nanoscale. 2022 Jun 9;14(22):8050-8059. doi: 10.1039/d2nr00512c.
Two-dimensional transition metal dichalcogenides provide flexible platforms for nanophotonic engineering due to their exceptional mechanical and optoelectronic properties. For example, continuous band gap tunability has been achieved in 2D TMDs by elastic strain engineering. Localized elastic deformations in nanobubbles behave as "artificial atoms" with a spatially varying band gap resulting in funnelling of excitons and photocarriers. Here we present a new method of nanobubble fabrication in monolayer 2D lateral heterostructures using high temperature superacid treatment. We fabricated MoS and WS nanobubbles and performed near-field imaging with nanoscale resolution using tip-enhanced photoluminescence (TEPL) spectroscopy. TEPL nanoimaging revealed the coupling between MoS and WS nanobubbles with a large synergistic PL enhancement due to the plasmonic tip, hot electrons, and exciton funnelling. We investigated the contributions of different enhancement mechanisms, and developed a quantum plasmonic model, in good agreement with the experiments. Our work opens new avenues in exploration of novel nanophotonic coupling schemes.
二维过渡金属二硫属化物因其卓越的机械和光电特性，为纳米光子工程提供了灵活的平台。例如，通过弹性应变工程已在二维过渡金属二硫属化物中实现了连续的带隙可调性。纳米气泡中的局部弹性变形表现为具有空间变化带隙的“人工原子”，导致激子和光载流子的漏斗效应。在此，我们展示了一种使用高温超强酸处理在单层二维横向异质结构中制造纳米气泡的新方法。我们制造了二硫化钼和二硫化钨纳米气泡，并使用尖端增强光致发光（TEPL）光谱进行了具有纳米级分辨率的近场成像。TEPL纳米成像揭示了二硫化钼和二硫化钨纳米气泡之间的耦合，由于等离子体尖端、热电子和激子漏斗效应，产生了大幅协同的光致发光增强。我们研究了不同增强机制的贡献，并开发了一个与实验结果高度吻合的量子等离子体模型。我们的工作为探索新型纳米光子耦合方案开辟了新途径。
