论文标题
单层WSE $ _2 $在粗糙金属基板上选择性增强尖锐缺陷排放线的起源
Origin of selective enhancement of sharp defect emission lines in monolayer WSe$_2$ on rough metal substrate
论文作者
论文摘要
过渡金属二核苷的原子薄层中的缺陷状态是单个光子发射的有希望的候选者。但是，这种量子发射的亮度通常很弱，并且伴随着不良影响，例如光谱扩散和强烈的背景发射。通过将单层WSE $ _2 $直接放在粗糙的金底物上，我们在这里显示出急剧下缺陷的激子峰的选择性增强，并与抑制的光谱扩散和强烈的背景发光的强烈淬火相结合。通过将实验数据与详细的电磁模拟相结合，我们揭示了这种选择性发光增强功能源于purcell效应的组合和激发电场的波长依赖性依赖于高的粗糙特征的尖端，并与局部菌株诱导的激元诱导的激子漏斗效应耦合。值得注意的是，插入WSE $ _2 $和AU膜之间的薄六角硼（HBN）三明治层会导致背景发光的强大增强，从而掩盖了尖锐的缺陷峰。研究结果表明，使用薄金属膜支撑的单层WSE $ _2 $的简单策略，该薄膜提供了具有高纯度，高亮度和抑制光谱扩散的量子光源的可能性。
The defect states in atomically thin layers of transition metal dichalcogenides are promising candidates for single photon emission. However, the brightness of such quantum emission is often weak, and is accompanied with undesirable effects like spectral diffusion and strong background emission. By placing a monolayer WSe$_2$ directly on a rough gold substrate, here we show a selective enhancement of sharp defect-bound exciton peaks, coupled with a suppressed spectral diffusion and strong quenching of background luminescence. By combining the experimental data with detailed electromagnetic simulations, we reveal that such selective luminescence enhancement originates from a combination of the Purcell effect and a wavelength dependent increment of the excitation electric field at the tips of tall rough features, coupled with a localized strain induced exciton funneling effect. Notably, insertion of a thin hexagonal Boron Nitride (hBN) sandwich layer between WSe$_2$ and the Au film results in a strong enhancement of the background luminescence, obscuring the sharp defect peaks. The findings demonstrate a simple strategy of using monolayer WSe$_2$ supported by thin metal film that offers a possibility of achieving quantum light sources with high purity, high brightness, and suppressed spectral diffusion.
