fig8

Figure 8. SEM images of a zinc oxide nanotube-nanowire mixed structure fabricated in an aqueous electrolyte containing (A) only NaHCO₃, in which < 5% of the substrate area was covered with nanotubes, and (B and C) both Na₂CO₃ and NaHCO₃. (D) TEM image showing a nanotube and a nanowire^[166]. Reproduced from Ref.^[166] with permission from the American Chemical Society.