Low aspect-ratio hemispherical nanopit surface texturing for enhancing light absorption in crystalline Si thin film-based solar cells

In this letter, we report light absorption enhancement in crystalline Si thin film-based solar cells through introducing low aspect-ratio hemispherical nanopit surface textures. Optical characteristics of the system are systematically investigated in terms of the structural parameters including nanopit diameter (D) and array periodicity (P) via simulation. An ultimate efficiency of similar to 35.7% is predicted when both D and P are similar to 700 nm, which is more than double of that (similar to 15.9%) of the flat Si film with the same thickness of 2 mu m. An understanding on the light absorption enhancement is provided based on the optical processes in the subwavelength structures. (C) 2011 American Institute of Physics. [doi:10.1063/1.3537810]