Fig. 4From: Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical EtchingSEM images of GaAs nanopillar arrays fabricated by Au-assisted chemical etching in solutions containing 0.01 mol dm−3 KMnO4 and 5, 10, or 20 mol dm−3 HF for 5 s at a 20 and b 45 °CBack to article page