Light Trapping Potential of Hexagonal Array Silicon Nanohole Structure for Solar Cell Application

Abstract

The reflectance of the hexagonal array silicon nanohole structure was systematically studied using various measurements and through simulations. It was found that the hexagonal array silicon nanohole can reduce the reflectance along the entire spectrum range by approximately 6%. It is suggested that the enhancement of the electric field intensity at short wavelength is mainly due to the large surface area provided by the nanohole structure, while multiple reflections occurring in the nanohole contribute to electric field enhancement in the long wavelength range. In addition, the simulation of a hexagonal array silicon nanohole coated with a thin layer of indium tin oxide (ITO) was carried out. The results show that reflectance is greatly decreased along nearly the entire spectrum range, except from 400 nm to 440 nm, and almost zero reflectance is achieved at wavelengths from 650 nm to 750 nm. The results provide a practical guideline to the design and fabrication of a low-reflectance, and as a consequence, a high-efficiency hexagonal array silicon nanohole solar cell.