Nematpour Abedin, Grilli Maria Luisa, Lancellotti Laura, Lisi Nicola
Energy Technologies and Renewable Sources Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Casaccia Research Centre, Via Anguillarese 301, 00123 Roma, Italy.
Energy Technologies and Renewable Sources Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Portici Research Centre, P.le E. Fermi 1, 80055 Portici, Italy.
Materials (Basel). 2022 Jan 4;15(1):352. doi: 10.3390/ma15010352.
Graphene is emerging as a promising material for the integration in the most common Si platform, capable to convey some of its unique properties to fabricate novel photonic and optoelectronic devices. For many real functions and devices however, graphene absorption is too low and must be enhanced. Among strategies, the use of an optical resonant cavity was recently proposed, and graphene absorption enhancement was demonstrated, both, by theoretical and experimental studies. This paper summarizes our recent progress in graphene absorption enhancement by means of Si/SiO-based Fabry-Perot filters fabricated by radiofrequency sputtering. Simulations and experimental achievements carried out during more than two years of investigations are reported here, detailing the technical expedients that were necessary to increase the single layer CVD graphene absorption first to 39% and then up to 84%. Graphene absorption increased when an asymmetric Fabry-Perot filter was applied rather than a symmetric one, and a further absorption increase was obtained when graphene was embedded in a reflective rather than a transmissive Fabry-Perot filter. Moreover, the effect of the incident angle of the electromagnetic radiation and of the polarization of the light was investigated in the case of the optimized reflective Fabry-Perot filter. Experimental challenges and precautions to avoid evaporation or sputtering induced damage on the graphene layers are described as well, disclosing some experimental procedures that may help other researchers to embed graphene inside PVD grown materials with minimal alterations.
石墨烯正成为一种很有前景的材料，可集成到最常见的硅平台中，能够将其一些独特特性传递给新型光子和光电器件的制造。然而，对于许多实际功能和器件而言，石墨烯的吸收率过低，必须提高。在各种策略中，最近有人提出使用光学谐振腔，并通过理论和实验研究证明了石墨烯吸收率的提高。本文总结了我们近期通过射频溅射制备的基于硅/二氧化硅的法布里-珀罗滤波器来提高石墨烯吸收率方面取得的进展。这里报告了在两年多的研究过程中进行的模拟和实验成果，详细介绍了将单层化学气相沉积石墨烯的吸收率先提高到39%，然后再提高到84%所需的技术手段。当应用非对称法布里-珀罗滤波器而非对称滤波器时，石墨烯的吸收率会提高；当石墨烯嵌入反射型而非透射型法布里-珀罗滤波器中时，吸收率会进一步提高。此外，在优化的反射型法布里-珀罗滤波器的情况下，研究了电磁辐射的入射角和光的偏振的影响。还描述了避免对石墨烯层造成蒸发或溅射诱导损伤的实验挑战和注意事项，揭示了一些可能有助于其他研究人员以最小改变将石墨烯嵌入物理气相沉积生长材料中的实验程序。
