COARSE-GRAINED SI FILMS FOR CRYSTALLINE SI THIN-FILM SOLAR CELLS PREPARED BY ZONE-MELTING RECRYSTALLIZATION

摘要

Zone-melting recrystallization (ZMR) is a technique which can dramatically improve the quality of Si films deposited on foreign substrates. Therefore this process also plays a key role for the fabrication of crystalline Si thin-film solar cells following the "high temperature route". The influence of substrate parameters on crystal quality is studied by ZMR experiments on different kind of Si wafers and on low cost Si ribbon material produced by the SSP (Silicon Sheets from Powder) process. The defect structure of recrystallized and epitaxially thickened Si films is correlated with crystal growth morphology observed in-situ during ZMR. Thin-film solar cells prepared from Si films on multicrystalline Si and SSP substrates are characterized. Efficiencies reach up to 12.3% on mc-Si and 11.3% on SSP substrates. The improvement of solar cell parameters by an emitter passivation is quantified.