The crystalline silicon (c-Si) solar cells with light-trapping structures can enhance light absorption within the semiconductor absorber layer, especially in thin-film crystalline silicon (c-Si) solar cells. Here we demonstrate that a dome surface light-trapping scheme for c-Si thin films, fabricated via laser interference lithography and chemical wet etching process, significantly enhances the light absorption within the c-Si layer. In this paper, we demonstrate its good antireflection ability and light trapping performance. As a result, an overall reflection down to 5.35% in the spectrum range of 400-1000nm wavelength was achieved, which is 7.8% lower than inverted pyramid without additional nitride coatings. To quantitatively evaluate the light trapping performance of the textures, the enhancement factor in the dome case is 45%, while for the pyramid texture the AE factors is only around 39.7%. In addition, the absorbed photocurrent density is 14.38 mA/cm<sup>2</sup> for a 2 μm silicon absorber layer at an incidence angle of 0°, which is 1.32 mA/ cm<sup>2</sup> higher than inverted pyramids. The proposed structure has the potential to play a key role in thin film solar cells.
Enhancing the light absorption in ultrathin-film silicon solar cells is important for improving efficiency and reducing cost. In this paper, we report a highly effecient cosine periodic nanostructure as light trapping texture. The design and fabrication as well as measurement of cosine nanotextures were presented. The optimized structure yields an average reflectance of 7.07% at an equivalent silicon thickness of 10μm, much better than planar and random pyramid structures. The measurements demonstrate that the absorptions in ultrathin film solar cells are very close to the Yablonovitch limit for the entire solar spectrum and insensitive to the angle of the light. This approach is applicable to various thicknesses and promising in future glass-based thin film solar cells.