新型微纳结构硅宽谱高效吸收效率的量化分析

Quantitative analysis for micro/nano-structure silicon with wide spectrum and high absorption efficiency

飞秒激光制备的微纳结构硅材料由于其在可见光和近红外波段都有很高的吸收而在硅基光电、光电探测器以及超疏水设备等方面都具有重要应用。然而,其高宽谱高效吸收特性的机理从没有被准确量化,这在很大程度上限制了这类材料的进一步发展与应用。通过实验,量化了飞秒激光制备的微纳结构硅的不同吸收影响因素,包括硅衬底的掺杂以及在激光制备过程中使用掺杂剂在材料中引入的杂质,激光制备过程中形成的增强光吸收的无序的表面微纳结构等因素。通过这些分析,确定了硅衬底的掺杂比激光制备过程中引入的硫杂质的掺杂对于红外波段的吸收有更大的贡献,此外,该种以硅衬底的掺杂为主要红外吸收介质的材料具有耐退火性。这些结果对设计和制造高效率的光电器件有着重要影响。

Due to the high absorption efficiency in both visible and infrared wave bands,micro/nano-structure silicon prepared by femtosecond laser has many important applications in the silicon-based optoelectronics, photoelectric detectors and super hydrophobic devices.However,the mechanism of the absorption characteristics with wide spectrum and high efficiency has never been quantified accurately, which limits further development and application of this kind of material.Therefore,we experimentally quantified the differentabsorption factors of the micro/nano-structure silicon prepared by femtosecond laser,including the dopant impurities in the silicon substrate,doping impurities induced during the laser fabrication process,absorption enhancement from the surface amorphous light-trapping structure.By these analyses,we determine that as compared to the doping sulfur impurities induced during the fabrication process,dopant impurities in the silicon substrate can contribute much more to the infrared absorption.Furthermore,the material is annealing-insensitive.These results have important influence on the design and manufacture of high efficiency optoelectronic devices.