Optical Absorption Enhancement: Optical Absorption Enhancement in Freestanding GaAs Thin Film Nanopyramid Arrays (Adv. Energy Mater. 10/2012)

III–V compound semiconductor multi-junction solar cells are the most efficient of all solar cells. However, in order to reduce high costs, ultra-thin films with advanced light management are desired. On page 1254, James S. Harris, Yi Cui, Dong Liang, and co-workers report that a 160-nm-thick GaAs thin film of nanopyramid arrays on flexible transparent superstrates demonstrates excellent optical absorption properties. Due to significant antireflection and light trapping effects, the double-sided nanostructures enhance the photon absorption in the thin film by over 80% at near normal incidence and over 100% at 40–70° incidence.