基于透明导电氧化物的近红外表面等离子体材料及相关器件的研究

Conventional noble metals such as gold and silver have been shown to be excellent plasmonic materials in visible range. However, in near infrared wave-range, due to the shortcomings such as higher losses, smaller resonant wavelength tunable range and incompatible with silicon CMOS technology, the metals are found to encounter bottleneck for further applications, particularly in the vicinity of the optical communication wavelength. In this project, based on combination of the advantages of ultra-low optical loss of transparent conductive oxides (TCO) such as ITO, AZO in NIR and high density of free electrons of gold, silver, and TiN, we propose a route to design and fabricate the hybrid plasmonic materials which are composed of TCO, metals, or TiN. The hybrid films will either have the TCO/metal/TCO sandwich structure, or own the configuration of TCO/TiN co-sputtering. The research will focus on make clear how the components, interfacial properties, as well as crystallinity of each layer affect the overall electrical and optical properties of the hybrid films. The novel localized surface plasmon resonance enhanced 1.55μm light source can be obtained by placing germanium quantum dots in Purcell cavity which is made of the above mentioned hybrid materials. This project will provide theoretical basis and experimental data for the further applications of hybrid SP materials in resonance enhanced optoelectronic devices, novel photovoltaic devices, and metamaterials.

传统的贵金属材料如Au，Ag已经被证明了在可见光波长范围内具有非常优良的表面等离子体特性。然而，在近红外区域，金属材料由于损耗较高、共振波长可调谐范围小以及与硅CMOS工艺不兼容等缺点阻碍了其在该波长范围，尤其是在光通讯波长附近的光电应用。本项目分别利用透明导电氧化物（TCO，如ITO，AZO）的近红外区超低损耗和Au, Ag, TiN的高密度自由电子优势，提出一种基于TCO并结合了Au，Ag或TiN的复合型薄膜结构的设计与制备方法，如TCO/metal/TCO的三明治结构，TCO/TiN的共溅射薄膜体系。重点研究各层薄膜的组分、界面性能、结晶特性等因素对整体复合薄膜电学性能和光学性能的影响。将该复合SP材料与硅基锗量子点相结合，通过理论建模、软件仿真与器件制作，获得一种基于局域表面等离子体共振增强效应的Purcell腔结构，以达到高效近红外硅基光源的要求。

透明导电氧化物（TCO）由于在可见光波段同时表现出很高的电导率和透过率而在光电子领域得到广泛的应用，本项目针对透明导电氧化物在近红外波段所具有的优良表面等离子特性以及参数可调谐性，对TCO，TCO/金属/TCO，TCO/TiN/TCO等多种成分与结构的新型近红外表面等离激元材料进行了深入的研究，并设计和制备了基于局域表面等离子体共振效应的近红外光致发光增强器件和大光学非线性折射率材料。同时，我们将研究对象扩展到了柔性透明导电材料PEDOT：PSS和中红外表面等离激元材料n型锗。本项目研究内容包括多种薄膜材料制备、介电常数色散曲线获取、表面极化等离激元激发、局域表面等离子体共振器件的制备和器件性能表征等多方面。我们的研究发现，透明导电氧化物及其复合材料是近红外区域性能优越的表面等离子体材料，在等离子体频率可调谐、与CMOS工艺兼容以及光学损耗等方面都优于贵金属材料。TCO能够有效增强近红外光源，尤其是光通信波段的发光效率，有机材料在近红外也能够有效激发表面等离激元，是潜在的柔性表面等离子体材料。n型锗是中红外优秀的表面等离子体材料，所构成的微纳结构能够激发局域表面等离子体共振共振，有效提升探测与传感信号，对于分子探测、生物医学、环境监测等领域的应用有重要的意义。