Development of anti-reflecting surfaces based on Si micropyramids and wet-chemically etched Si nanowire arrays

Abstract

In this paper experimental results on study of optical properties of Si wafers with surface textures in form of Si random pyramids, Si nanowire arrays, and pyramidal Si combined with Si nanowire arrays are presented. It is shown that the use of the metal-assisted chemical etching method allows to fabricate an array of Si nanowires, and a complex structure composed of Si pyramids with nanotextured side faces which possess a high degree of anti-reflecting ability. Experimental results of the absorbance and reflectance spectra measuring demonstrated that in comparison with other textures, the structures with nanotextured pyramids' side faces exhibit the highest absorption (~ 98 %) and lowest reflection values (~ 1 %) in all range of wavelength (300-1100 nm). The concept of a complex structure combining the advantages of pyramids and Si nanowires to achieve the omnidirectional light absorption and overcome the directional dependence of photovoltaic performance is discussed.