【作者】 张伟；

【导师】 李相银；

【作者基本信息】 南京理工大学 ， 光学工程， 2017， 博士

【摘要】 过去十年里,微纳光学和光子学得到了迅猛发展。以亚波长光栅、光子晶体、超材料为代表的周期性微纳光子功能器件在光通信、显示照明、信息存储、生命科学、能源技术等领域得到了广泛的关注和研究。本文主要研究了周期性微纳光子功能结构在薄膜太阳能电池、生物传感器及量子点发光器件中的应用,具体研究内容与结果归纳如下:(1)基于一维及二维复合光栅设计了多种薄膜太阳能电池陷光结构模型,并采用严格耦合波分析法及时域有限差分法进行计算和模拟。研究结果表明,纳米减反结构及表面等离子体激元效应可以有效提高光在薄膜太阳能电池中的吸收效率。入射窗口层采用一维光栅结构可以有效提高TM偏振光的吸收,但对TE光作用不大,而采用在x和y方向上周期相同的二维对称结构则可以消除光偏振态对陷光效果的影响。在背反射极上引入二维金属纳米结构可激发局域表面等离子体激元效应,在薄膜太阳能电池结构周期为220nm,上表面减介质柱直径为154nm,背反射极为金属-电介质-金属纳米结构,且内金属柱半径为16.5nm,内环半径为60.5nm,外环半径为88nm时,理想短路电流高达39.1mA/cm2,接近于晶硅太阳能电池短路电流极限值42.2mA/cm2。(2)研究了二维环形光子晶体在生物传感器中的应用。我们采用平面波展开法系统研究了二维环形光子晶体的带隙结构及其随环形折射率变化时的变化特征。结果表明,环形空气孔单元的引入能有效压低二维光子晶体的带隙上带边工作频率,从而获得比普通空气孔型二维光子晶体更高的传感灵敏度。通过对环形空气单元结构优化设计,得到的二维环形光子晶体折射率探测灵敏度高达738nm/RIU,超越了目前空气孔型二维光子晶体的探测灵敏度极限值500nm/RIU。同时,我们提出了一种交叉偏振式方法来定义二维光子晶体传感器的工作方式,这种方法需要光子晶体同时稳定地支持TE和TM两种偏振方式,得到的灵敏度是两种偏振灵敏度之和,因而特别适合二维环形光子晶体工作。仿真结果表明,最优的二维环形光子晶体结构可将折射率灵敏度提高到1190nm/RIU,有效促进了二维光子晶体生物传感器的发展和应用。(3)研究了二维环形光子晶体在量子点发光器件中的应用。我们将二维环形光子晶体微腔应用于InAs量子点发光器件模型中,通过对微腔结构的设计与参数优化,实现了在TE和TM两种偏振态下,光子晶体平面内在1.3μm附近均有一个非常尖的传输峰,且平面内Q值达到了 105～106量级。二维环形光子晶体微腔可有效提高量子点发光器件的发光效率,这得益于其对两种偏振态的良好支持。同时,我们采用FIB对二维环形光子晶体微腔进行制备,结果表明,在对刻蚀深度没有严格要求的前提下,FIB通过优化刻蚀参数能够满足空气环的刻蚀精度和高重复性要求。通过光致发光谱测试,验证了二维光子晶体量子点发光器件的性能,达到了预期设计效果。更多还原

【Abstract】 In the past ten years,micro-nano optics and photonics are rapidly developed.Periodical micro-nano photonic functional devices such as sub-wavelength gratings,photonic crystals and metamaterials have been widely researched in many fields,for example,optical communication,display illumination,information storage,life sciences,energy technologies,and so on.This paper mainly studied the design,manufacture and application of periodical micro-nano photonic structures in thin film solar cells,biological sensors and quantum dot light emitting devices.The specific research contents and results are summarized as follows:(1)We have designed a variety of light trapping structures in thin film solar cells based on 1-D and 2-D composite gratings,and we used rigorous coupled wave analysis(RCWA)and finite difference time domain(FDTD)method for calculation and simulation.The results show that the nano antireflection structure and surface plasmon polaritons could improve the light absorption efficiency vastly in thin-film solar cells.1-D grating window enhances the TM polarized light absorption effectively,but it is not sensitive to TE light.However,the 2-D symmetrical structure in x-y plane could eliminate the effect of light polarization.On the back reflection electrode,localized surface plasmon resonance effect could be induced by 2-D nano metallic structures.When the period is 220 nm,the diameter of surface dielectric cylinder is 154 nm,the reflector is metal-dielectric-metal structure and the radius of metal cylinder is 16.5nm,the inner and outer radius of the metal ring is 60.5nm and 88nm,the photocurrent reaches up to 39.1mA/cm2,close to the limit value of photocurrent which is 42.2mA/cm2.(2)We studied 2-D annular photonic crystals in the application of biosensors.We systematically calculated the band gap of 2-D annular photonic crystal and its variation characteristics when the annular refractive index changes.The results show that the annular hole unit could effectively depress the working frequency of upper band gap in 2-D photonic crystals,accordingly gaining greater sensitivity than ordinary air holes.The refractive index detection sensitivity of biosensor based on 2-D annular photonic crystal could be as high as 738 nm/RIU,beyond the limit of 2-D air hole photonic crystal biosensor as 500 nm/RIU.Meanwhile,we firstly put forward the cross polarization approach to define the working styles of 2-D photonic crystal biosensor.This method needs the support of TE and TM polarization working mode at the same time,and the sensitivity is the sum of two polarizations,therefore,it is especially suitable for 2-D annular photonic crystals.The simulation results show that the optimal structure increases the refractive index sensitivity to 1190nm/RIU,and it will effectively promote the development and application of 2-D photonic crystal biosensors.(3)We studied 2-D annular photonic crystals in the application of quantum dot light emitting devices.The 2-D annular photonic crystal microcavity is applied in InAs quantum dot light emitting device model,and we achieved a very sharp transmission peak near 1.3μm in the photonic crystal plane both at the TE and TM polarization thanks to the good support of both two polarizations in 2-D annular photonic crystal.The Q value in the plane reached 105～106 orders of magnitude,which can effectively improve the InAs quantum dot light emitting efficiency in this band.At the same time,we adopted FIB for the preparation of 2-D annular photonic crystal microcavity.The results show that FIB could satisfy the requirement of etching precision and high repeatability of the air ring after optimizing etching parameters.In addition,we experimentally verified the performance of 2-D photonic crystal quantum dot light emitting device with the photoluminescence test and the results are in conformity with the simulation.更多还原