Fabrication of solar cells using the epilift technique

The Epilift technique allows the growth and detachment of good quality, single crystal silicon films on silicon substrates. Since the substrates only act as a growth template, they can be re-used, offering the potential for substantial cost reductions. However, the processing of solar cells on Epilift layers introduces significant challenges as a result of the fact that the layers are thin and perforated. We have obtained good results by performing most of the processing prior to detachment of the layer from the substrate. An interdigitated rear contact design created by laser patterning allows the specific features of epilift layers to be optimally exploited. Individual 1cm² cells with a SiO₂ antireflection coating have displayed efficiencies in excess of 13%, while a 50cm² mini-module has displayed an efficiency of 10.9%.