论文标题
2D半导体中尖端引起的纳米工程菌株,带隙和激子动力学
Tip-induced nano-engineering of strain, bandgap, and exciton dynamics in 2D semiconductors
论文作者
论文摘要
带隙,吸收和发射能的可调性,光致发光(PL)量子产率,激子传输和过渡金属二甲硅烷基(TMD)单层中的能量转移为广泛的超薄光子设备提供了新的功能。最近的应变工程方法使我们能够调整其中的某些特性,但具有实时和空间特征的纳米级动态控制仍然是一个挑战。在这里,我们在WSE2单层中展示了自然形成的皱纹的动态纳米机械应变工程,并使用高光谱适应性尖端增强PL(A-TEPL)光谱对纳米光谱性质进行了实时研究。 First, we characterize nanoscale wrinkles through hyperspectral a-TEPL nano-imaging with <15 nm spatial resolution which reveals the modified nano-excitonic properties by the induced tensile strain at the wrinkle apex, e.g., an increase in the quantum yield due to the exciton funneling, decrease in PL energy up to ~10 meV, and a symmetry change in the TEPL spectra caused by the重新配置的电子带结构。然后,我们通过按原子力尖端控制按下和释放皱纹顶点来动态设计局部应变。这种纳米机械应变工程使我们能够以可逆的方式调整纳米级的激子动力学和发射特性。此外,我们展示了皱纹发射的系统切换和调制平台,该平台为原子较薄的半导体中的稳健,可调和超型纳米光源提供了一种新的策略。
The tunability of the bandgap, absorption and emission energies, photoluminescence (PL) quantum yield, exciton transport, and energy transfer in transition metal dichalcogenide (TMD) monolayers provides a new class of functions for a wide range of ultrathin photonic devices. Recent strain-engineering approaches have enabled us to tune some of these properties, yet dynamic control at the nanoscale with real-time and -space characterizations remains a challenge. Here, we demonstrate a dynamic nano-mechanical strain-engineering of naturally-formed wrinkles in a WSe2 monolayer, with real-time investigation of nano-spectroscopic properties using hyperspectral adaptive tip-enhanced PL (a-TEPL) spectroscopy. First, we characterize nanoscale wrinkles through hyperspectral a-TEPL nano-imaging with <15 nm spatial resolution which reveals the modified nano-excitonic properties by the induced tensile strain at the wrinkle apex, e.g., an increase in the quantum yield due to the exciton funneling, decrease in PL energy up to ~10 meV, and a symmetry change in the TEPL spectra caused by the reconfigured electronic bandstructure. We then dynamically engineer the local strain by pressing and releasing the wrinkle apex through an atomic force tip control. This nano-mechanical strain-engineering allows us to tune the exciton dynamics and emission properties at the nanoscale in a reversible fashion. In addition, we demonstrate a systematic switching and modulation platform of the wrinkle emission, which provides a new strategy for robust, tunable, and ultracompact nano-optical sources in atomically thin semiconductors.