飞秒激光制备单晶硅表面微结构研究详解.docVIP

摘要 (SEM)和分光光度计分别对结构的形貌特征和光学特性进行了测量。结果表明：采用底角为2o的四棱锥镜相位形成四光束干涉，并通过10×物镜聚焦，在激光功率25 mW，曝光时间30 s时，可以形成间距约为3.3 μm的密排凹坑微结构；所形成的凹坑结构具有良好的减反效果，对1.2 μm-2 μm近红外波段的透过率相对抛光硅平均提高了11.5%。最后对所做工作的详细总结，分析了工作中取得的成绩和需要改进之处，并提出了本课题有待于进一步深入研究的问题。 ABSTRACT The fabrication of surface micro-structure has many interesting applications, such as the changes of the material surface color, hydrophobic properties and surface roughness. The most important applications, for silicon surface micro-structure, are the change of the optical properties. In this paper, we summarize the ways to form surface micro-structure, detailed introduce the formation process and mechanism of the preparation of silicon surface micro-structure by using the ultra-short pulse laser, and the formation process of the femtosecond laser pulse induce silicon surface micro-structure has been further investigated. When the femtosecond laser pulse irradiate at the silicon surface, and its fluence beyond a certain threshold value, the micro-nano scale structure will form spontaneous at the radiation area. The micro-structure, on one hand, broaden the light-absorb area of the silicon surface, on the other hand, leads to the incident light reflect repeatedly between the side walls of the adjacent structures, which form a so-called “light trapping effect” to promote the absorption and transmission of the incident light. In addition, the formation of the micro-structure results in the refraction index mutation of the interface between air and substrate translate into a gradient change, thereby reducing the reflectivity. We detailed investigate the formation process and mechanism of the silicon surface micro-structure irradiated by the ultra-short pulse laser, and we mainly explore how the parameter of the femtosecond laser influence on the silicon surface micro-structure formation, such as pulse number, scan speed and polarization direction. We also research how the variation of the silicon surface micro-structure morphology rel