Figure 4From: NH4 + directed assembly of zinc oxide micro-tubes from nanoflakes FESEM images of ZnO nanostructures. Obtained from the precipitation reaction between ZnSO4ยท7H2O and (NH4)2CO3 with the ratio at (A) 2.4:1.0, (B) 2.0:1.0, (C) 1.6:1.0, and (D) 1.0:1.0.Back to article page