Screen-printed epitaxial silicon thin-film solar cells with 13.8% efficiency

Amidst the different silicon thin-film systems, the epitaxial thin-film solar cell represents an approach with interesting potential. Consisting of a thin active c-Si layer grown epitaxially on top of a low-quality c-Si substrate, it can be implemented into solar cell production lines without major changes in the current industrial process sequences. Within this work, 30-m-thick epitaxial layers on non-textured and highly doped monocrystalline Czochralski (Cz) and multicrys talline (mc) Si substrates have been prepared by CVD. Confirmed efficiencies of 138% on Cz and 123% on mc-Si substrates have been achieved by applying an industrial process scheme based on tube and in-line phosphorus diffusion, as well as screen-printed front and back contacts fired through a SiNx anti-reflection coating. An extensive solar cell characterisation, including infrared lock-in therm ography and spectral response measurements is presented.