ZONE-MELTING RECRYSTALLIZATION OF SILICON THIN-FILMS FOR SOLAR-CELL APPLICATION

Zone-melting recrystallization (ZMR) has been applied successfully to fabricate a thin-film silicon solar cell with high conversion efficien cy that also has the potential to lower the material cost. It is found that seeding front an Si substrate during ZMR is nor necessary for hi gh-quality thin-film Si with a low defect density and the dominant (10 0) crystallographic orientation. This feature is very important becaus e one can separate the thin-film Si from the substrate in order to obt ain a flexible solar cell and the substrate can be recycled. Lowering the scanning speed of the upper movable carbon strip heater has proved to be most effective for high-quality crystal. In order to realize th in-film Si solar cells, a 60-mu m thick Si active layer is deposited b y chemical vapour deposition on recrystallized Si film. Pyramidal shap e formation at the surface for light confinement by using (100) orient ation and low-energy H+ ion irradiation for the passivation of crystal defects has Been applied to the fabrication of thin-film Si solar cel ls and we achieved high conversion efficiencies of more than 14% for a 10 x 10 cm(2) cell and 16% for a 2 x 2 cm(2) cell.