Periodic upright nanopyramid fabricated by ultraviolet curable nanoimprint lithography for thin film solar cells

Abstract

In this work, a periodic upright nanopyramid structure was developed for light harvesting applications suitable for thin film solar cells. The periodic inverted nanopyramid structure was fabricated on Si substrate by laser interference lithography (LIL) and subsequent pattern transfer by combined reactive ion etching and KOH wet etching. The silicon substrate was used as a master mould in the replication process utilising ultraviolet curable nanoimprint lithography (UV-NIL) process. The inverted nanopyramid patterns were transferred onto OrmoStamp resist layer to form upright pyramids on glass substrates by UV-NIL. The replicated periodic upright nanopyramid structures can be used as light trapping structures in thin film solar cells and as soft mould in the 3D imprint process.