Giant ambipolar diffusion constant of n-i-p-i doping superlattices

The analytical expression for the ambipolar in-plane diffusion constant of excess carriers in n-i-p-i doping superlattices is derived. Shockley-Haynes--type experiments quantitatively confirm the predicted huge enhancement of the diffusion constant (in the tested case by factors of about 300) and the long diffusion lengths.