Single Material, Near-Infrared Wavelength Selective Absorber Based on Optical Index Tuning with Tamm Plasmons

Abstract

Near-infrared (NIR) wavelength-selective absorbers have attracted attention in many applications, such as photodetectors, photovoltaics, image sensors. Conventionally, artificial nanostructures have been introduced to implement a tunable absorber with a narrow emission peak. However, since these structures should have well-aligned and finely arranged structures, all the above sophisticated structures not only demand time/cost consuming fabrication process but also make a barrier for scalable fabrication. To achieve the convenience of large-area nanofabrication with selective narrow absorption, planar multilayer structures based on surface-state resonances have been introduced which can offer many advantages compared with 2D or 3D nanostructures. Tamm plasmons structures (TPs) have been introduced to design highly selective absorber with overcoming technical issues. The TPs consists of a metallic layer and distributed Bragg reflector (DBR) layers. In this work, we demonstrate the single material TPs by modulating the optical index. Consequently, we optimized TPs with porous a-Ge having a high absorptance at a specific NIR wavelength through RCWA. Furthermore, by the oblique-angle deposition (OAD) process, we fabricated the TPs and measured absorptance for fabricated the TPs.