Ultra-thin broadband solar absorber based on stadium-shaped silicon nanowire arrays

Abstract

This paper investigates how the dimensions and arrangements of stadium silicon nanowires (NWs) affect their absorption properties. Compared to other NWs, the structure proposed here has a simple geometry, while its absorption rate is comparable to that of very complex structures. It is shown that changing the cross-section of NW from circular (or rectangular) to a stadium shape leads to change in the position and the number of absorption modes of the NW. In a special case, these modes result in the maximum absorption inside NWs. Another method used in this paper to attain broadband absorption is utilization of multiple NWs which have different geometries. However, the maximum enhancement is achieved using non-close packed NW. These structures can support more cavity modes, while NW scattering leads to broadening of the absorption spectra. All the structures are optimized using particle swarm optimizations. Using these optimized structures, it is viable to enhance the absorption by solar cells without introducing more absorbent materials. Graphical Abstract

Light absorption enhancement of silicon solar cell based on horizontal nanowire arrays

“…In these studies, the geometrical design of NWs has been modified to increase absorption in SCs 48 – 53 …”

“…In these studies, the geometrical design of NWs has been modified to increase absorption in SCs. [48][49][50][51][52][53] Absorption in an array of NWs can be quite different from in single NWs due to the interconnection between the NWs. Optical antenna effects are also influenced in NW arrays.…”