Theoretical investigation of nano-muffin and inverted nano-pyramid surface textures for energy harvesting in very thin c-Si solar cells

Abstract

Nano-scale surface textures have been developed as photon management schemes for crystalline silicon (c-Si) solar cells with very thin absorber layers to compensate for light absorption losses. This paper investigates the optical properties of periodic nano-muffin and inverted nano-pyramid surface textures, simulated using the Rigorous Coupled Wave Analysis (RCWA) method. Obtained results are compared against those of a planar silicon film with equal thickness. The simulation results demonstrate that nano-muffin and inverted nano-pyramid surface textures with a small aspect ratio are able to achieve substantial absorption enhancement over a broadband wavelength range. Further investigation indicates that nano-muffin surface textures could trap light by concentrating light within a volume close to the texture (micro-lensing effect). With such nano-scale textures, light trapping similar to that of much larger scale textures can be achieved. Copyright © 2014 Materials Research Society.