Compensation of the dangling-bond space charge in amorphous p-i-n solar cells, by graded low-level doping in the intrinsic layer, was demonstrated experimentally. Carrier collection in p-i-n cells without doping indicated that the degraded state space charge was largely positive, and that B doping should therefore be beneficial. Solar cells with linearly decreasing B doping profiles were shown to yield homogeneous collection in the intrinsic layer, and a red-light conversion efficiency which was superior to that of undoped cells after light-soaking. The optimum dopant concentration was shown to be a direct measure of the degraded state defect density.

D.Fischer, A.V.Shah: Applied Physics Letters, 1994, 65[8], 986-8