Wide-Angle Antireflection Effect of Subwavelength Structures for Solar Cells

The angle-dependent reflectivity of several surface structures was analyzed and evaluated with the viewpoint of solar cell applications. Numerical analysis showed that a Si subwavelength structure (SWS) maintains a lower reflectivity at large incident angles than conventional light-trapping techniques such as a random pyramid texture, and that it can contribute to increasing the output power of solar cells under oblique irradiation. This wide-angle antireflection effect was demonstrated by fabricating test crystalline Si cells with several surface structures including a SWS and measuring their angle-dependent short-circuit current densities.