General Solution Behavior

Figure 29.15 shows the influence of this increased surface recombination the right electrode (at d1).

The hole density is increased in the bulk; the minimum is shifted further into the bulk and is not as deep compared to Fig. 29.15. This can be understood by the increased diffusion current toward the right surface, which brings p(d1) closer to p10. The electron density distribution, however, is essentially unchanged since n > p. The quasi-Fermi levels collapse now at x = 0 and at x = d1.

Close to the neutral contact, EFn remains constant (as n does) while EFp(x) decreases in reverse bias until it joins EFn at x = d1.

In summary, strong surface recombination influences minority carriers through­out the thin device: p(x), EFp(x), and therefore also jp(x) are substantially changed. The majority carrier properties, however, are essentially unchanged, ex­cept for a comparatively small reduction of the DRO-range width when the minority carrier density exceeds the majority dopant density. This causes a slight steepening of the characteristics before attaining saturation.

Updated: August 18, 2015 — 10:34 am