为了增强量子点的定向发光强度, 提出了一种由硅柱二聚体和二氧化钛圆盘组成的复合纳米天线结构。利用时域有限差分方法系统研究了硅柱二聚体的轴参数、截面类型以及复合纳米天线结构对量子点定向发光增强的影响。结果表明, 对于中心波长为600nm的量子点, 硅柱二聚体的轴参数对量子点的发光影响不大, 椭圆形截面的硅柱二聚体可以实现较大的量子点发光增强。此外, 在复合纳米天线的作用下, 不仅可以获得较大的量子效率增强, 还可以实现量子点高度定向的发射效果, 量子效率增强约6倍, 定向收集效率可以达到50%。

In order to enhance the directional luminescence intensity of quantum dots, a hybrid nano-antenna structure composed of a silicon column dimer and a titania dioxide disk was proposed. The effects of the axis parameters, profile type of silicon column dimer and hybrid nano-antenna structure on the directional emission enhancement of quantum dot were investigated by using the finite difference time domain method. The results show that the silicon column dimer with different axial parameters has little effect on quantum dot emission at the central wavelength of 600nm, and silicon column dimer with elliptical profile can achieve larger quantum dot luminescence enhancement. In addition, under the effect of hybrid nano-antenna, both the quantum efficiency enhancement and the highly-directional emission effect of quantum dot can be achieved, and the former is enhanced by about 6 times and the directional collection efficiency can reach 50%.