Fig. 4From: Controllable Fabrication of Non-Close-Packed Colloidal Nanoparticle Arrays by Ion Beam EtchingSEM images of PS nanoparticles etched for 5 min with the ion voltage of 1 kV and the beam current of 5 (a), 7 (b), 9 (c), and 10 mA (d), respectivelyBack to article page