Fig. 6.

Depiction of band diagrams versus position away from the surface z, at a position x > x₀ (upper row) where the bulk is p-type, and at a position x < x₀ (lower row) where the bulk is n-type. The surface may be n-type, intrinsic, or p-type. Depending on the combination of surface and bulk properties, recombination is enhanced or suppressed at the surface, as shown in the various cases. Electrons (holes) are represented with red (blue) dots, and arrows indicate the drift direction of each carrier type due to the surface electric field.