Fig. 6. SEM images and corresponding EDS elemental distributing map of sphere-shaped Au–Ag NPs arrays with periodic length of 500 nm on quartz sheet with varying Ag content by controlling deposition time of Ag film using periodic Au spherical NPs arrays as the second deposition template; in images marked (a–d), the deposing time of Ag film is 20, 30, 60 and 120 s, respectively.
