After drying at 60°C for 30 min, Au was coated onto the silica sphere array by e-beam evaporation. In order to ensure adhesion, 20 nm of Cr as an insertion layer was also deposited on the surface of the silica sphere array before

deposition of the Wortmannin Au layer. Figure 1 Schematic diagram for fabrication procedure. Schematic diagram for the fabrication of the Au-coated silica sphere array as a top electrode of ZnO NRA-based NGs: (i) preparation of colloidal solution (i.e., dispersed by silica spheres) on the PET substrate, (ii) rolling and drying the colloidal solution, and (iii) e-beam evaporation of Au onto the silica sphere array. Results and discussion Figure 2a shows the field-emission scanning electron microscope (FE-SEM) images of (i) the deposited silica sphere on the PET substrate and (ii) the Au-coated silica sphere array on the PET substrate by e-beam evaporation with a deposition rate of 5 Å/s for 400 s. As shown in the FE-SEM image of Figure 2a (i), the multilayer of silica spheres of approximately 75- to 100-nm diameters was coated on the PET substrate, which could provide a rough surface of the template for Au coating as a top electrode. When Au was deposited on the silica sphere array in Figure 2a

(ii), it covered well the whole surface of the silica sphere array with a somewhat thick and angulate morphology. For click here comparison of the surface roughness in topography, 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 array on the PET PD-1/PD-L1 Inhibitor 3 substrate are shown in Figure 2b. As can be seen in the AFM topographic images for each sample, it is clearly observed that the Au-coated silica sphere array had such a rough surface as compared to the surface of the Au film on the PET substrate. From the roughness analysis, the root mean square

(RMS) surface roughness of (i) and (ii) were 5.78 and 88.27 nm, respectively. Also, the Au-coated silica sphere array exhibited a high average particle height of 259.6 nm, while the Au film on the PET substrate exhibited a low average Methane monooxygenase particle height of 5.78 nm. This highly rough surface of the Au-coated silica sphere array could lead to a good electrode for efficient bending of ZnO nanorods on NG devices. Figure 2 FE-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. Figure 3 shows (a) the measured I-V curves and (b) simulation results for the strain distributions of (i) the flat Au film on PET and (ii) the Au-coated silica sphere array on PET. To obtain the sheet resistivity (R s), the I-V curves were characterized by a line four-point probe measurement setup with a fixed distance between the probes (1 mm).