All Silicon MIR super absorber using fractal metasurfaces

Abstract

Abstract The study of blackbody radiation led to the development of quantum mechanics more than a century ago. A blackbody is an ideal absorber, as it absorbs all the electromagnetic radiation that illuminates it. No radiation is transmitted through it, and none is reflected. Now, "bodies" with high absorption qualities are crucial in numerous scientific and technological fields. Perfect absorbers can be used as photodetectors, thermal images, microbolometers, and thermal photovoltaic solar energy conversion. The spectrum of Mid-infrared (MIR) wavelengths offers numerous advantages for a wide range of applications. Among these applications is chemical and biological detection. In this study, we propose a fractal broadband silicon (Si) absorber. The proposed structure is composed of three layers: metal, dielectric, and metal (MDM), with the metal being n-type D-Si and the dielectric being Silicon Carbide (SiC). The structural composition displays a broad absorption profile across a broad spectrum of infrared wavelengths, ranging from 3 to 9 µm. The architectural design was derived from the Sierpinski carpet fractal, and different building locks were simulated to attain optimal absorption. Silicon that has been doped exhibits superior performance compared to metals in energy harvesting applications that utilize plasmonics at the mid-infrared range. Typically, semiconductors exhibit rough surfaces than noble metals, resulting in lower scattering losses. Moreover, silicon presents various advantages, including compatibility with complementary metal-oxide-semiconductor (CMOS) and simple manufacturing through conventional silicon fabrication methods. In addition, the utilization of doped silicon material in the mid-IR region facilitates the creation of microscale integrated plasmonic devices. This combination enables the production of numerous traditional plasmonic devices. The 2D finite element method (FEM) approach via COMSOL software is used to obtain the numerical results. The suggested fractal absorber exhibits high absorption enhancement in the Mid-IR range.