Inapplicability of diffusion theory with strong recombination

The collection of charge carriers from the preceding layer in semiconductor solar cells with strong recombination is computed on the basis of a 'transit' model and the results are compared with those obtained on the basis of the commonly used diffusion theory. It is shown that even in the case when the free path length for a collision with recombination is 10 times greater than the free path length for an elastic collision, the difference in the collection coefficients computed in the transit and diffusion approximations is about 60%.