Nanoimprinted Tio₂ sol–gel passivating diffraction gratings for solar cell applications

We report the fabrication and characterization of TiO 2 sol–gel diffraction gratings on silicon substrates by using nanoimprint lithography. The gratings are homogeneous and free of defects and cover an area of 25 cm 2 . Minority carrier lifetimes of up to 900 µs for imprinted samples under illumination are reported, which Kelvin probe measurements indicate is due to light‐generated negative charge in the films. The structures reported here are very promising as light‐trapping, passivating coatings for solar cells.