Mellor Null, Alexander Virgil and Hauser, Hubert and Wellens, Christine and Benick, Jan and Eisenlohr, Johannes and Peters, Marius and Guttowski, Aron and Tobías Galicia, Ignacio and Martí Vega, Antonio and Luque López, Antonio and Bläsi, Benedikt
Nanoimprinted diffraction gratings for crystalline silicon solar cells: implementation, characterization and simulation.
"Optics Express", v. 21
Light trapping is becoming of increasing importance in crystalline silicon solar cells as thinner wafers are used to reduce costs. In this work, we report on light trapping by rear-side diffraction gratings produced by nano-imprint lithography using interference lithography as the mastering technology. Gratings fabricated on crystalline silicon wafers are shown to provide significant absorption enhancements. Through a combination of optical measurement and simulation, it is shown that the crossed grating provides better absorption enhancement than the linear grating, and that the parasitic reflector absorption is reduced by planarizing the rear reflector, leading to an increase in the useful absorption in the silicon. Finally, electro-optical simulations are performed of solar cells employing the fabricated grating structures to estimate efficiency enhancement potential.