Band bending due to charged dangling bonds in amorphous silicon p-i-n solar cells

Poisson´s equation is solved for the band bending, electric field, and position dependence of the dangling-bond density in the i layer of hydrogenated amorphous silicon p-i-n solar cells using the Fermi energy dependence of charged dangling-bond density predicted by thermodynamic theory. Within about 100 Å of the n-i interface, where the Fermi energy approaches the conduction band edge, more than 10¹⁸ cm ^-3 negatively charged dangling bonds can be formed. This space charge increases the electric field near the n-i interface, thereby improving cell performance. Hole trapping and stabilization in these dangling bonds may account for the reduction in cell efficiency after light soaking