Almost zero reflectance of a silicon oxynitride/porous silicon double layer antireflection coating for silicon photovoltaic cells

Reflectance spectrum calculations for a silicon oxynitride (SiO(x)N(y))-porous silicon (PS) double layer antireflection coating is performed using the matrix method. The results are compared with the corresponding spectrum of diamond-like carbon (DLC)/PS and SiO(2)/TiO(2) double layer coatings. A lower reflectance in the visible and infrared regions of the solar spectrum for the SiO(x)N(y)/PS double layer is obtained, especially in the 450-600 nm spectral range (with a flat reflectance response remaining as low as approximate to 0.01%), which corresponds to the maximum intensity of solar irradiation. These findings are of importance in solar cell applications.