Surface nanostructure optimization for solar energy harvesting in Si thin film based solar cells

The solar energy harvesting of Si thin films with Si nanocone or nanopillar array decorated surfaces is systematically studied by simulation for the first time. It is found that the high and broad-width light absorption around 2.5 eV is the key to achieve high efficiencies for both structures. Nanostructure dimensions are optimized based on the enhanced light scattering, and thus the prolongated optical path around this energy. This work provides a practical guideline to design and fabricate Si thin film solar cells with high efficiency matching the bulk Si record.