Discerning passivation mechanisms at a-Si:H/c-Si interfaces by means of photoconductance measurements

The photoconductance decay (PCD) measurement is a fast and simple method to characterize amorphous/crystalline (a-Si: H/c-Si) silicon interfaces for high-efficiency solar cells. However, PCD only yields information concerning the overall recombination rate in the structure. To overcome this limitation, we have developed and validated a computer-aided PCD (CA-PCD) analysis method to determine the defect density of recombination-active dangling bonds at the interface and the potential drop in the crystalline absorber adjacent to the interface. As a practical example, we investigate a-Si: H (p)/a-Si: H(i)/c-Si(n) layer stacks and show that the CA-PCD method is capable of discerning the influence of field-effect and defect passivation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3590254]