Figure 2From: Efficient piezoelectric ZnO nanogenerators based on Au-coated silica sphere array electrodeFE-SEM and AFM images. (a) FE-SEM images of (i) the deposited silica sphere array on the PET substrate and (ii) the Au-coated silica sphere array on PET. (b) 5 μm × 5 μm scan AFM images and histograms of (i) the Au film on the PET substrate and (ii) the Au-coated silica sphere on the PET substrate.Back to article page