Integration of a 2D Periodic Nanopattern Into Thin Film Polycrystalline Silicon Solar Cells by Nanoimprint Lithography

摘要

The integration of two-dimensional (2D) periodic nanopattern defined bynanoimprint lithography and dry etching into aluminum induced crystallization(AIC) based polycrystalline silicon (Poly-Si) thin film solar cells isinvestigated experimentally. Compared to the unpatterned cell an increase of 6%in the light absorption has been achieved thanks to the nanopattern which, inturn, increased the short circuit current from 20.6 mA/cm2 to 23.8 mA/cm2. Theefficiency, on the other hand, has limitedly increased from 6.4% to 6.7%. Weshow using the transfer length method (TLM) that the surface topographymodification caused by the nanopattern has increased the sheet resistance ofthe antireflection coating (ARC) layer as well as the contact resistancebetween the ARC layer and the emitter front contacts. This, in turn, resultedin increased series resistance of the nanopatterned cell which has translatedinto a decreased fill factor, explaining the limited increase in efficiency.