Numerical solar cell simulation including multiple diffused reflection at the rear surface

Photocarrier generation rate and cell reflectance models including multiple diffused reflection at the rear surface of solar cells for numerical simulation have been described. Multiple diffused reflection has been formulated using a two-directional angle distribution of light intensity. Every time the light is reflected at the rear surface, the same distribution on independent two angles is added, so that the light diffusion expands more. The conversion efficiency of sample silicon solar cells has been computed, using the two-dimensional device simulator with these models. The cell thickness dependence of conversion efficiency for the rear surface with various roughnesses has been investigated and compared with that for the planer surface.