Comprehensive design analysis of ZnO anti-reflection nanostructures for Si solar cells

Abstract

Six different shapes of zinc oxide (ZnO) nanostructured antireflective coatings on Si substrate, namely hemispheres, pyramids, motheye-like, cubes, rods and hexagonal prisms, were modeled numerically using finite element simulation, by solving Maxwell wave equation for periodic nanostructure arrays. COMSOL Multiphysics commercial package was used to perform the simulation by adopting the wave optics module. Geometrical parameters including structure size and period were studied in order to obtain better insight on how light and matter interaction is affected by structure geometry. However, among the studied structure geometries, hemispherical ones have the worst optical performance with a maximum reflectance of 45% for a 20 nm hemisphere radius. Pyramidal, motheye and cubic shapes yielded an intermediate optical performance while rod and hexagonal shapes revealed a minimum reflectance (less than 5%) values over a wide range of wavelengths and also showing interesting interference patterns.