等离激元增强金属-硅组合微结构近红外吸收  

Plasmonic Enhanced Near-Infrared Absorption of Metal-Silicon Composite Microstructure

作　　者：杨柳 蒋世磊[1] 孙国斌[1] 杨鹏飞 季雪淞 张锦[1] Liu Yang;Shilei Jiang;Guobin Sun;Pengfei Yang;Xuesong Ji;Jin Zhang(School of Optoelectronic Engineering,Xi'an Technological University,Xi'an,Shaanxi 710021,China)

机构地区：[1]西安工业大学光电工程学院,陕西西安710021

出　　处：《光学学报》2020年第21期156-162,共7页Acta Optica Sinica

基　　金：陕西省教育厅重点实验室科研计划(18JS053);陕西省科技厅重点实验室项目(2013SZS14-P01);西安工业大学基金(XAGDXJJ15001);西安工业大学光电学院基金(15GDYJY03)。

摘　　要：亚波长光栅结构的光学表面具有减反特性,这种特性在光电转换效率的应用方面具有重要意义。为了提高硅基光栅结构在近红外波段(0.78~2.50μm)的吸收率,采用在硅表面光栅空隙处加入金属Ag纳米颗粒和Al2O3介质层的方法,利用FDTD软件仿真研究不同的组合结构及颗粒的直径对光吸收率的影响,分析不同的工作波长下组合结构中特征截面的光强分布。实验结果表明,当光栅线/间比为1∶1、周期为1μm、周期凹槽内放置两层直径为0.25μm的金属Ag颗粒、且凹槽内金属颗粒上方填充覆盖Al2O3介质层时,该组合微结构在近红外波段范围内的平均吸收率理论上可达到0.463,实现吸收增强的效果。在光电转换器件的应用方面,金属颗粒-硅光栅-介质层组合微结构可以增强光吸收,进而提高光电转换效率。The optical surface of sub-wavelength grating structures has anti-reflection characteristics, which are of great significance for the application of photoelectric conversion efficiency. In order to improve the absorptivity of silicon-based grating structures in the near-infrared band (0.78-2.50 μm), we add Ag nanoparticles and an Al2O3 dielectric layer to the gap of the silicon surface grating. Furthermore, the FDTD software is employed to investigate the influence of different composite structures and particle diameters on the light absorptivity and analyze the light intensity distribution of the characteristic section in the composite structure at different working wavelengths. The experimental results show that in the context of a line/space ratio of 1∶1 and a period of 1 μm for the grating, as well as two-layer Ag particles (diameter of 0.25 μm) cover with an Al2O3 dielectric layer in the periodic groove, the average absorptivity of the composite microstructure in the near-infrared band can theoretically reach 0.463, achieving absorption enhancement. It follows that the metal-silicon gratingdielectric layer composite structure can enhance light absorption, in the application of photoelectric conversion devices, thereby improving photoelectric conversion efficiency.

关 键 词：表面光学 光吸收增强 近红外吸收 金属-硅栅-匹配介质层组合结构 表面等离激元 

分 类 号：O436[机械工程—光学工程]