Accurate modeling of light trapping in thin film silicon solar cells

An attempt is made to assess the accuracy of the simplifying assumption of total retransmission of light inside the "escape" or "loss" cone which is made in many models of optical confinement in thin-film silicon solar cells. A closed form expression is derived for the absorption enhancement factor as a function of the refractive index in the low-absorption limit for a thin-film cell with a flat front surface and a lambertian back reflector. Numerical calculations are carried out to investigate similar systems with antireflection coatings, and the investigation of cells with a textured front surface is achieved using a modified version of the existing ray-tracing computer simulation program TEXTURE.