球形硅基光学微腔中光电转换效应的研究

Spherical silicon micro- and nano optical cavity is a new kind of silicon based photonic material. Due to the high refractive index of silicon, it is able to strongly trap light in 3D, and thus is expected to be an optical resonance cavity with high performance. Further considering the intrinsic semiconductor properties of silicon and the design of the surface heterogeneous structure, this project will study both experimentally and theoretically the photo-electric conversion effects of the spherical silicon micro- and nano- photonic cavity based materials. It is expected that the key factors and the mechanism of the enhancements of the photo-electric conversion based on 3D silicon photonic resonators can be revealed, and related potential applications in new generation micro- and nano- opto-electric functional materials and devices can be discussed. Specifically speaking, based on our previous works, we will optimize the fabrication method, and design a new 2D or 3D spherical silicon micro- and nano- optical cavity based photonic materials which have high absorption efficiency in visible and near-infrared region according to the real silicon optical parameters. We will also analysis the solar energy absorption and conversion efficiency of our designed silicon photonic materials by using the detailed balance thermodynamic theory. Last but not the least, with the design of surface heterogeneous structure, we will fabricate the materials and measure the photo-electric conversion properties. This project could consequently provide theoretical as well as experimental results for the development of the related research directions.

球形硅基光学微腔是一种新型的硅基微纳光子学材料。由于硅的高折射率性质，球形硅基光学微腔可以在三维强局域光场，具有优异的光学共振腔等光物理特性。结合材料本征的半导体性质以及表面异质结构设计，本项目拟同时在实验和理论上研究球形硅基光学微腔中的光电转换效应，揭示具有三维光学共振特性的硅基光子材料对硅光电转换效应的关键影响因素和增强机理，并分析其在新型微纳光电功能材料和器件等方面的应用前景。具体来说，在前期工作的基础上，我们将优化材料的制备工艺，结合实际的硅材料光学参数设计对可见和近红外光具有强吸收能力的基于球形硅基光学微腔的复杂二维和三维光学结构。同时，我们将利用热力学精细平衡理论，分析所设计的复杂光学结构对太阳能吸收和光电转换效率的影响。最后，我们将引入表面异质结构，测试所制备材料的光电转换性能。本项目所研究的新型光学硅基材料中的光电转换效应将为相关方向的发展提供一定的理论和实验依据。

微纳尺寸光学微腔是新型光子材料最基本的组成单元。由于其可以在纳米尺度三维局域光场，一直是在微尺度操控光的有利工具。同时结合材料本征的特性，例如半导体的吸收特性，可以作为高效的光能转化材料。本项目在实施过程中，主要研究了：第一从材料上开发了新型硅基球形颗粒光学微腔的制备技术；第二从理论上分析了在纳米尺度极限的光能吸收效率并研究了具体的增强吸收方案；第三从应用上展现了微纳尺寸光学微腔在光热、光化学、生物传感和结构色等领域的巨大潜力，开发了相关光纳米探针技术。具体的成果有开发了两套制备硅基光学微腔的生产工艺，包括生产多分散尺寸硅颗粒的化学气相沉积技术和生产单分散硅颗粒的高压液相成核技术；拓展耦合模理论得到了亚波长材料的极限吸收截面并研究了增益材料和近零折射率材料对吸收截面的增强效应；获得了可在生物体系内应用的纳米化学传感器探针。发表相关包括Advanced Materials，Optics Express，Physical Review B，Analytical Chemistry等SCI论文9篇。