基于ZnO/金属纳米周期结构的等离激元辅助光发射增强研究

Surface plasmon enhanced light emission using plasmon energy coupling and scattering on the surface of metal nanoparticles has gained increasing interest in the field of luminescent device research. Using this method, the light-emitting efficiency of ZnO can be improved more than 10 times. The microstructure of the metal interface plays a crucial role in light efficiency enhancement. Systematical studies and reports on the influences of metallic periodic nanostructures on ZnO light emission characteristics worldwide are currently insufficient. This project aims to construct a ZnO/metallic periodic nanostructure system. The following procedures were carried out in ascertaining the nature of the metal and dielectric film up to the design and control of metal microstructures: (1) exploring the energy trapping and scattering behavior of surface plasmon in microstructure interface and the physical mechanism of auxiliary light emission enhancement through systematical experiments; (2) optimizing metallic periodic nanostructure and achieving the maximized plasmon enhanced ultraviolet light emission of ZnO; (3) adjusting the resonant frequency of the surface plasmon using the structural parameters of periodic nanostructures and achieving variable wavelength light emission enhancements. On this foundation,we would further try to integrate metallic periodic nanostructure in ZnO-based PN junction to achieve variable wavelength electroluminescent enhancements and to provide theoretical and experimental bases to obtain a high-performance full-color ZnO-based LED.

利用金属纳米颗粒表面等离激元的能量耦合及散射实现发光材料的辅助光发射增强是目前发光器件研究领域的前沿热点，采用该方法可将ZnO材料的光致发光效率提高超过十倍，在此过程中金属界面的微细结构起至关重要的作用。目前国际上尚缺少金属纳米周期结构对ZnO光发射特性影响的系统研究报道。本项目拟构建ZnO/金属纳米周期结构体系，从金属与介质膜的性质、金属微结构的设计和控制方面入手，开展下列研究：（1）通过系统的实验探求表面等离激元在界面微细结构中的共振散射行为及辅助光发射增强的物理机制；（2）优化金属纳米周期结构，实现ZnO等离激元辅助紫外光发射增强的最大化；（3）探索利用纳米周期结构参数调整金属/ZnO界面等离激元的共振频率，力争实现可变波长光发射增强。在此基础上，进一步尝试在ZnO基PN结中集成金属纳米周期结构，实现ZnO的可变波长电致发光增强，为获得ZnO基高性能全彩LED提供理论和实验基础。

宽禁带半导体/金属纳米复合结构的制备及其奇异性能是当今新材料领域的前沿研究课题。本项目紧扣该研究热点，按照项目研究计划开展科研工作，取得了如下研究进展：（1）利用溅射方法获得不同颗粒尺寸的随机岛状Ag纳米颗粒和ZnO薄膜复合结构，实现了对ZnO薄膜近带边光发射的九倍增强，分析得到了Ag纳米颗粒表面局域等离激元辅助ZnO光发射增强的物理机制；（2）利用模板法制备了不同周期尺寸的二维金属纳米周期结构并和ZnO薄膜构成复合结构，观察到异于金属随机纳米颗粒/ZnO薄膜的光发射增强现象，实现了对ZnO薄膜可见光波段的多波长光发射增强，测试分析结果表明金属纳米周期结构对等离激元和光子之间的动量失配补偿起到了关键作用；（3）构建了ZnO/GaN异质结构，利用二维Ag纳米周期结构实现了对ZnO/GaN异质结构电致发光可见光波段的光发射增强，初步明确了金属纳米周期结构对ZnO基LED电致发光的增强作用。（4）利用ZnO半导体纳米棒作为增益介质，构建了能够实现紫外波段表面等离激元传播的波导结构，为后续亚波长尺度下的紫外激光光源研究奠定了基础。