Surface-concentrated light and efficient carrier collection in microhole-patterned Si solar cells

We investigate photovoltaic characteristics of crystalline Si solar cells with microhole-patterned surface. We compare patterned samples with different hole-widths and periods with a planar counterpart. From the finitedifference time-domain simulation, the patterned and planar samples are expected to have similar short circuit current density, Jsc (difference: 1.2%). In contrast, the difference in the measured Jsc is as large as 12.6%. The simulated optical field patterns reveal that the sample with more significantly concentrated light near the surface has higher quantum efficiency due to more efficient carrier collection. We report the highest efficiency of 15.6% among the hole-patterned solar cells.