Optical simulation of periodic surface texturing on ultrathin amorphous silicon solar cells

In this paper, we study the effect of sinusoidal textures on light absorption properties in an ultrathin amorphous silicon (a-Si) solar cell with conductive transparent layer composed of dielectric/metal/dielectric layers by using 2-D optical simulation. We found that the absorption at visible region can be enhanced at an optimized period (P) and height (H) combination, despite the weakening of a cavity resonance at the a-Si layer. The short-circuit current density for the structure with P = 300 nm and H = 180 nm showed a 52% higher value than that of the reference. A random texture was also simulated, and the absorption spectrum of the a-Si layer was reproduced by superposition of those with sinusoidal textures weighted by power spectrum density of the random texture, which implies the superiority of sinusoidal texture over random texture.