The modification of optical and electronic properties of transition metal dichalcogenides via mechanical deformation has been widely studied. Their ability to withstand large deformations before rupture has enabled large tunability of the bandgap, and further, the spatially varying strain has been shown to control the spatial distribution of the bandgap and lead to effects such as carrier funneling. Monolayer transition metal dichalcogenides exhibit a significant piezoelectric effect that could couple to a spatially inhomogeneous strain distribution to influence electronic and optical behavior. We investigate both experimentally and theoretically an example case of photoluminescence in structures with a strain distribution similar to that employed in single-photon emitters but generated here via nanoindentation. Using a mechanical model for strain induced by nanoindentation, we show that piezoelectricity can result in charge densities reaching 1012 e/cm2 and can generate electrostatic potential variations on the order of ±0.1 V across the suspended monolayer. We analyze the implications of these results for luminescence and exciton transport in monolayer transition metal dichalcogenides with spatially varying strain.

中文翻译：

---

单层过渡金属二硫属化物中应变相关的发光和压电性

通过机械变形对过渡金属二硫属化物的光学和电子性质进行了广泛研究。它们在破裂前承受大变形的能力使带隙具有较大的可调性，此外，空间变化的应变已被证明可以控制带隙的空间分布并导致载流子漏斗等效应。单层过渡金属二硫属化物表现出显着的压电效应，可以耦合到空间不均匀的应变分布，从而影响电子和光学行为。我们在实验和理论上研究了结构中光致发光的示例，其应变分布类似于单光子发射器中采用的应变分布，但通过纳米压痕在此处生成。使用由纳米压痕引起的应变的机械模型，我们表明压电可以导致电荷密度达到 1012 e/cm2，并且可以在悬浮的单层上产生 ±0.1 V 量级的静电电势变化。我们分析了这些结果对具有空间变化应变的单层过渡金属二硫属化物中的发光和激子传输的影响。