Combined Electrostatic-Covalent Building of Au NPs Multilayers and Their Size-Enhanced Cohesive and SERS Properties
Figure 7
AFM pictures in tapping mode of the last NPs layer at the different (successive) steps of the formation of the complete multilayer structure on the substrate. From (a) to (c), the images correspond to the 15 nm-sized NPs, and from (d) to (f), to the 5 nm NPs. 15 nm NPs: (a) first layer, zoom in: nm² AFM phase contrast image of a zoom in of the 2D-assembly of the NPs, (b) second layer, (c) fourth layer; the scale is ( μm); 5 nm NPs: (d) first layer, zoom in: nm² AFM phase contrast image of a zoom in of the 2D-assembly of the NPs. (e) Second layer, (f) fourth layer; the scale is ( μm).
