过渡金属二硫属化物光子学的试验平台：Mb 2 O3与二聚体纳米尺度光子学中光发射增强的功效
Testbeds for Transition Metal Dichalcogenide Photonics: Efficacy of Light Emission Enhancement in Monomer vs. Dimer Nanoscale Antennae
摘要：
单层过渡金属二硫属化物是非常适合用于光子学的材料，因为它们结合了良好定义的可调谐直接带隙和没有悬挂键的自钝化表面。然而，这些2D材料的原子厚度导致低的光吸收，限制了可实现的光致发光强度。原则上，这种发射可以通过纳米级天线增强，从而导致：增大的吸收截面，增强泵效率，b.主要通过将天线光模体积减小到衍射极限之外，经由Purcell因子加速内部发射速率，以及c.发射极偶极子与自由空间波长的改进的阻抗匹配。等离子体二聚体天线显示数量级的热点领域的增强时，发射器正好位于midgap。然而，2D材料不能生长或容易地转移以驻留在金属二聚体腔的中间间隙中。此外，需要在腔和发射材料之间的间隔层以避免非辐射复合通道。使用计算和实验方法，在这项工作中，我们表明，从一个2D发射器-单体天线腔系统的发射增强的竞争对手，在大大减少光刻工作的二聚体。我们合理化这一发现表明，在二聚体天线的发射增强并不具体源于二聚体腔的间隙，但平均效果源于有效的腔截面下，每个光学腔的发射2D膜位于。特别是，我们测试了不同的二聚体和单体天线的几何形状的阵列，并观察到一个代表性的3倍更高的发射单体和二聚体空腔相比，化学气相沉积合成的WS 2薄片的固有发射。
英文摘要：
Monolayer transition metal dichalcogenides are uniquely-qualified materials for photonics because they combine well defined tunable direct band gaps and selfpassivated surfaces without dangling bonds. However, the atomic thickness of these 2D materials results in low photo absorption limiting the achievable photo luminescence intensity. Such emission can, in principle, be enhanced via nanoscale antennae resulting in; a. an increased absorption cross-section enhancing pump efficiency, b. an acceleration of the internal emission rate via the Purcell factor mainly by reducing the antennas optical mode volume beyond the diffraction limit, and c. improved impedance matching of the emitter dipole to the freespace wavelength. Plasmonic dimer antennae show orders of magnitude hot-spot field enhancements when an emitter is positioned exactly at the midgap. However, a 2D material cannot be grown, or easily transferred, to reside in mid-gap of the metallic dimer cavity. In addition, a spacer layer between the cavity and the emissive material is required to avoid non-radiative recombination channels. Using both computational and experimental methods, in this work we show that the emission enhancement from a 2D emitter- monomer antenna cavity system rivals that of dimers at much reduced lithographic effort. We rationalize this finding by showing that the emission enhancement in dimer antennae does not specifically originate from the gap of the dimer cavity, but is an average effect originating from the effective cavity crosssection taken below each optical cavity where the emitting 2D film is located. In particular, we test an array of different dimer and monomer antenna geometries and observe a representative 3x higher emission for both monomer and dimer cavities as compared to intrinsic emission of Chemical Vapor Deposition synthesized WS2 flakes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
