一种增强量子点远场定向发光的金属银纳米屋顶结构

A Novel Silver Nanodome Structure for Enhancing Directional Fluorescence Emission in Far Field

为了提高生物检测的灵敏度,增强量子点的远场定向发光强度显得尤为重要。因此提出一种周期分布在SiO_2隔层及金属银反射板上的金属银纳米屋顶结构,其中每个屋顶结构的半径为162.5nm,且量子点位于中间两个屋顶结构的缝隙内。使用时域有限差分算法,研究了量子点位于不同位置以及不同数量的金属银纳米屋顶结构对量子点远场发光强度的影响。计算表明当有四个纳米屋顶结构,且量子点处于中间两个屋顶结构的缝隙内部时,可以有效地提高量子点的远场发光强度,相较没有屋顶结构时发光强度提高了4倍以上,从而可以提高生物检测的灵敏度。

It is crucial to enhance the far-field directional emission of quantum dots （QDs） in order to improve the sensitivity of bio-deteetion. In this paper, we propose a novel and effective photonic structure composed of periodically distributed silver nanodomes on a SiO2 film and silver back reflectors. The radius of each nanodome structure is 162.5 nm, and the QD is located in the gap between adjacent silver nanodomes. The finite difference time-domain （FDTD） method is used to investigate the effect of different QD positions and different quantities of nanodomes on the emission intensity of QDs. The results show that when there are four nanodomes and the QD is located in the gap between adjacent nanodomes, the emission intensity of QDs in the far field is improved by more than four times compared to that of the nanodome free structure. The proposed structure will improve the sensitivity of biological detection.