【作者】 周冰；

【导师】 李东升； 杨德仁；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2010， 硕士

【摘要】 太阳能发电在解决全球能源危机,以及减缓温室效应方面有着巨大的潜在应用。作为半导体和微电子工业中最重要的基础材料,硅以其高储量、较为成熟的工艺、污染小、较高的转换效率、稳定性好等优势成为了太阳能光电池研究开发的重点材料。其中,硅薄膜电池在节约电池成本方面具有巨大的优势,是近年来研究的重点。然而,由于非晶硅的光学禁带宽度在1.7ev左右,对太阳辐射光谱的长波段吸收较弱,使其光电转换效率较低,另外,由于其载流子扩散长度的限制,很难通过进一步降低薄膜厚度来减少成本,这些都严重影响了硅在光伏市场上的推广应用。将金属等离激元共振用于增强太阳能电池的效率,是提高太阳能电池效率的研究热点之一。本文将表面等离激元用于提高非晶硅薄膜吸收,不仅在表面等离激元增强薄膜吸收方面有重要的理论探索意义,而且在太阳能电池领域具有良好的应用前景。此外,本文还将表面等离激元共振用于增强薄膜的发光强度,取得较为不错的增强效果。本文制备了金属银纳米颗粒结构,研究了影响其形貌和表面等离激元共振特性的因素,在此基础上,将金属银颗粒用于增强非晶硅薄膜的吸收及用于增强Y₂O₃;Yb³⁺薄膜的发光强度,并且分别研究了增强吸收和增强发光的机理。主要内容如下:（1）利用电子束蒸发法（EBE）制备了Ag纳米颗粒,研究了衬底温度,热处理温度等对其形貌和表面等离激元特性的影响,利用后续热处理法改变颗粒形貌来调节其表面等离激元共振峰的位置,还研究了通过改变周围介电材料环境来调节银纳米颗粒的表面等离激元共振峰的位置。实验结果表明,通过改变银颗粒的介电环境、生长温度以及热处理温度,可以达到调节银颗粒LSP共振特性的目的。（2）利用银纳米颗粒增强了非晶硅薄膜的吸收,结果表明,在适当尺寸的银纳米颗粒作用下,非晶硅薄膜对长波长光的吸收可以得到有效增强。在银纳米颗粒的作用下,入射光在非晶硅中的光学路径得到了增加,从而增强非晶硅对入射光的吸收。（3）利用Ag纳米颗粒的局域表面等离激元增强了Y₂O₃:Yb³⁺薄膜的发光。结果表明,表面等离激元增强了激发过程,从而增强薄膜荧光发光。更多还原

【Abstract】 There is huge potential for solar energy in solving global energy crisis and slowing down global warming.As the most basic material in semiconductor industries, silicon has many advantages for solar cells such as high reserves,mature technology, high efficiency and stability.Amorphous silicon thin-film solar cells,compared to single crystal and polycrystalline silicon solar cells,enjoy many outstanding advantages,such as lighter weight,larger optical absorption coefficient,better anti-radiation performance,lower cost and so on.However,since the optical band gap of amorphous silicon is approximate 1.7 eV,it results the small optical absorption coefficient at large wavelengths of solar radiation spectrum,as well as low photoelectric conversion efficiency.In addition,it is difficult to reduce the cost by further decreasing film thickness because the carrier diffusion length of amorphous silicon is just about 100 nm,which seriously affects the silicon photovoltaic market in the popularization and application.Then using surface plasmon to enhance the efficiency of amorphous silicon thin-film solar cells has become a hot topic in recent years.Evidentsly,using surface plasmon to enhance light absorption is expected to find wide potential applications in solar cells.In this thesis,metal nanoparticles were produced,and the factors that affect the morphology and suface palsmon resonance properties of metal particles were investigated.Then we used the suface palsmon of Ag nanostructures to increase the optical absorption efficiency of a-Si films.Finally,we used the suface palsmon of Ag nanostructures to increase the light emission of Y₂O₃:Yb³⁺ films.The primary significant results were follows:（1） Ag nanoparticles were prepared by electron beam evaporation.We found the morphology and surface plasmon of Ag nanoparticles dependent on temperature.And Subsequent thermal processing could change the morphology of Ag nanoparticles and tune the surface plasmon resonance wavelength.And with different dielectric materials around the Ag nanoparticles,surface plasmon of Ag nanoparticles could be tunned.（2） By adjusting the size of Ag nanoparticles,the optical absorption of a-Si thin film solar cells can be optimized.The average reflection value of a-Si films for the long wavelength range of optical spectra is reduced by evaporating Ag nanoparticles onto the a-Si films.（3） The photoluminescence of Y₂O₃:Yb³⁺ films was enhanced by coupling with surface plasmon of Ag nanoparticles and the mechanism was investigated.The results show that photoluminescence enhancement resulted from the enhancement of excitation efficiency.And it was found that the photoluminescne enhancement is related to the Ag nanoparticles size.更多还原