硅纳米结构提高发光器件辐射强度研究

Study on Silicon Nanostructures to Improve Radiation Intensity of Light Emitting Devices

半导体硅纳米粒子具有许多新奇的电磁特性,成为了近年光电子学的研究热点。为了提高量子点(QD)光致发光器件的发光强度,文章提出了一种由两个尺寸不同的硅纳米正方体组成的二聚体结构。通过时域有限差分(FDTD)法,分别从荧光激发率增强和量子产率增强两个方面研究了硅纳米二聚体对QD发光的增强作用。研究结果表明,不同尺寸的硅纳米正方体复合二聚体可以对硒化镉(CdSe)QD的发光产生增强作用;并且当两个硅纳米正方体的边长和间隔逐渐变小时,QD的荧光激发率增强倍数和量子产率提高倍数都呈现出逐渐增大的趋势。特别地,当两个硅纳米正方体的边长都是100 nm、间隔为20 nm时,硅纳米二聚体结构可达最优,且CdSe QD的荧光强度可得到约24倍的增强。

Semiconductor silicon nanoparticles have many novel electromagnetic properties and have became a research hotspot in optoelectronics in recent years.In order to improve the luminescence intensity of Quantum Dot(QD)photoluminescence devices,a dimer composed of two silicon nano-cubes of different sizes is proposed.By the Finite Difference Time Domain(FDTD)method,the luminescence enhancement of QD by silicon nano-dimers is studied in terms of fluorescence excitation rate enhancement and quantum yield enhancement.The results show that the dimer composed of two silicon cubes with different sizes can enhance the luminescence of CdSe QDs.When the side length of the two silicon nano-cubes and the gap between them getting smaller,the fluorescence excitation rate enhancement factor and the quantum yield enhancement factor of the QDs tend to increase gradually.In particular,when the side lengths of two silicon nano-cubes are 100 nm and the gap of the silicon dimer is 20 nm,the structure of silicon nano-dimer is optimal,and the fluorescence intensity of CdSe QDs can be enhanced by about 24 times.