Coarse-grained crystalline silicon thin film solar cells on laser perforated SiO2 barrier layers

Coarse-grained silicon layers for crystalline silicon thin film (CSiTF) solar cells have been obtained by recrystallization of a thin silicon CVD layer on different silicon substrates via seeding holes in a SiO₂ barrier layer. In the past, the perforation of the barrier layer was done by photolithography and wet chemical etching. Now these steps are being substituted by laser ablation. Patterns with different distances between the seeding holes have been tested. The depth of laser damage has been evaluated. After recrystallization and epitaxial thickening, frontside and backside contacted CSiTF solar cells have been manufactured. Conversion efficiencies up to 9.9% are only slightly below those on photolithographically perforated barrier layers