AFM topography of Ag samples of various thicknesses. The very thin layers show the formation of discrete nanoparticles on the substrate. As the layer thickness increases, the nanoparticles coalesce into a uniform film, forming grains of increasingly larger sizes. Nominal layer thickness: (a) 1.1 nm, (b) 3.4 nm, (c) 5.7 nm, (d) 7 nm, (e) 11 nm, (f) 14.1 nm, (g) 21 nm, (h) 30 nm and (i) 50 nm.