Understanding of a-Si:H(p)/c-Si(n) heterojunction solar cell through analysis of cells with point-contacted p/n junction

Abstract

We fabricated point-contacted a-Si:H(p)/c-Si(n) heterojunction solar cells using patterned SiO2 and investigated their electrical properties using the light current-voltage (I-V) curve and Suns-V,, measurements. The light I-V curves showed bias-dependent changes according to the applied voltage in the point-contacted cells, especially in the samples with a long distance between the point-contacted junctions. The Suns-V,, measurements showed that the bias-dependence of the light I-V curves did not originate from the recombination in the SiO2/Si or a-Si:H(p)/c-Si(n) interface, but from the series resistances. It is possible to explain the bias-dependent light I-V curve in terms of the conductivity of a-Si:H(p) and difference in the electrical contact properties between a-Si:H(p), ZnO and c-Si(n). These results mean that the electrical properties of the a-Si:H(p) layer and the contact properties with this layer are also critical to obtain a high J(sc) and fill factor in n-type based Si heterojunction solar cells. (C) 2009 Elsevier B.V. All rights reserved.