Plan-view SEM images. (a) Faceted Si nanostructures. (b) AFM topographic image where inset shows the 2D FFT. (c, d) After growing AZO films on nanofaceted Si having thicknesses of 30 and 75 nm, respectively. The black arrows indicate the direction of ionbeam bombardment, whereas the yellow arrows represent the direction of AZO flux during sputter deposition.