Light trapping in thin crystalline silicon solar cells

Optimally designed thin crystalline silicon solar cells (<50-μm thick) have performance and cost advantages over conventional thick devices. The modeling and fabrication of light-trapping devices are described. Thin (30-μm-thick) Si-film layers are formed on textured silicon substrates. The back surface of the thin Si film layers are passivated with SiO₂ coatings. Long-wavelength light is confined through total internal reflections. The analysis of fabricated devices reveals the presence of the enhanced absorption predicted by the light-trapping model. Efficiencies for these structures reach 9.4%, among the highest reported for crystalline silicon devices of this thickness