Design of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials by genetic algorithm

Abstract

Designs of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials are optimized using a genetic algorithm. Co-sputtered and low-refractive-index materials allow the fine-tuning of refractive index, which is required to achieve optimum anti-reflection characteristics. The algorithm minimizes reflection over a wide range of wavelengths and incident angles, and includes material dispersion. Designs of antireflection coatings for silicon-based image sensors and solar cells, as well as triple-junction GaInP/GaAs/Ge solar cells are presented, and are shown to have significant performance advantages over conventional coatings. Nano-porous low-refractive-index layers are found to comprise generally half of the layers in an optimized antireflection coating, which underscores the importance of nano-porous layers for high-performance broadband and omnidirectional antireflection coatings.

Realization of an extremely low reflectance surface based on InP porous nanostructures for application to photoelectrochemical solar cells

“…Photosensitive devices such as photodetectors in long-wavelength optical fiber communication systems [1,2] and high-efficiency solar cells with multi-junction structures [3] are excellent examples of technologies that utilize the superb optical properties of InP-based systems. With the aforementioned devices, however, surface reflection is a serious problem that degrades the device performance because is reduces the efficiency of photon energy conversion [4]. Surface texturing of V-grooves [5][6][7], formation of insulator films [8], wide bandgap semiconductor films [9], and transparent conducting oxide films [10] have been investigated as anti-reflective layers on top of InP.…”

Rear Side Diffractive Gratings for Silicon Wafer Solar Cells

“…Since in this sub-wavelength domain the light is not able to resolve the spatial features, an exact periodicity is not required. Therefore, also randomly arranged nanorods [25][26][27] or nanosponges [28] are perfectly suited for the purpose of reducing Fresnel reflection losses and have been considered in the past for integration into solar cells. If the effective refractive index profile is discontinuous, as in the case of binary gratings, the reduction of reflection losses will not cover an as broad spectral range but still a good performance can be achieved for the relevant spectral range [5].…”

Design and mechanism of cost-effective and highly efficient ultrathin (< 0.5 μm) GaAs solar cells employing nano/micro-hemisphere surface texturing

“…9 On the other hand, strong light reflection (> 30%) originating from the large refractive index difference between GaAs and the circumstance, e.g., air or vacuum for spacecraft applications demands the development of advanced antireflection coatings (ARCs) not only suppressing light reflection in a wide energy range but also with high stability and/or long-term endurance. [10][11][12] It will further increase the cost and complicate the manufacturing procedure of the related solar cells. 10,12 Aiming at lowering material consumption and quality requirement, and also at efficient and stable antireflection design, we propose a nano/micro-hemisphere array textured ultrathin filmbased GaAs solar cell configuration.…”