Leendertz, C.; Mingirulli, N.; Schulze, T.F.; Kleider, J.P.; Rech, B.; Korte, L.: Physical Insight into Interface Passivation of a-Si:H/c-Si Heterostructures by Analysis of Injection-dependent Lifetime and Band Bending. In: De Santi, G.F. [u.a.] [Eds.] : 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain. EU PVSECMunich: WIP, 2010. - ISBN 3-936338-26-4, p. 1377-1381
Abstract:
To reveal the interface passivation mechanisms at amorphous/crystalline silicon interfaces, we employan advanced simulation model to analyze injection-dependent effective carrier lifetime obtained by photoconductance measurements. We show that it is possible to distinguish between passivation by field effect and bysaturation of recombination-active defects using this analysis method. The separation of these effects requires asound model for the injection-dependent band bending in the structure that governs the field effect passivation andthus has a strong influence on the effective lifetime in the low-injection region. Applying the model to experimentaldata, we gain insight into the physics that governs the interface recombination in an a-Si:H(p)/a-Si:H(i)/c-Si(n) layerstack. We show that it is possible to extract the potential drop in the crystalline Si absorber and the increase ininterface defect density with increasing emitter doping, as well as its decrease with a-Si:H(i) layer thickness. Inconclusion, this data analysis, based on a modeling approach, reveals additional information on the nature ofinterface passivation, as compared to analyzing lifetime data only.