Results
and discussion Figure 1 shows the typical SEM images of Ag nanosheets that were electrodeposited in an ultra-dilute electrolyte in the potentiodynamic mode (V R = 15 V, V O = 0.2 V, 100 Hz, and 3%) for 120 min. Ag nanosheets had a width up to approximately 10 μm and a thickness of approximately 30 nm and were grown on the selleck inhibitor facetted Ag nanowires. In comparison, when the AgNO3 concentration was 0.2 mM, the facetted granular Ag islands grew with the size of 0.2 to 2 μm, as shown in Figure 2a. With the further increase of AgNO3 Tipifarnib ic50 concentration up to 2 mM, the granular islands were densely generated and formed a granular (columnar) layer, as shown in Figure 2b. This indicates that the growth of facetted nanowires and nanosheets shown in Figure 1 was closely related to the dilute concentration. Figure 1 Typical SEM images
of Ag nanosheets. (a) Typical 13°-tilted SEM images of Ag nanosheets grown on a substrate and (b) a higher magnified SEM image of a Ag nanosheet. (The inset indicates a higher magnified top-view SEM image.). Figure 2 Typical SEM images of Ag deposits with AgNO 3 concentration. Cross-sectional SEM images of Ag deposits deposited in the electrolytes of (a) 0.2 and (b) 2 mM AgNO3 for 120 min (V R = 15 V, V O = 0.2 V, 100 Hz, and 3%). (The insets denote the top-view SEM images.). The time-dependent growth of the Ag nanosheets was examined by varying the deposition learn more time as 20, 40, 70, and 120 min, respectively, as shown in Figure 3a,b,c,d. The growth
occurred in three stages. Phosphoprotein phosphatase First, the nucleation of polygonal islands on a substrate occurred, as shown in Figure 3a. The polygonal nuclei were randomly generated on the whole surface of substrate. Second, one-dimensional growth was driven in a specific direction by strong interface anisotropy between the polygonal islands and the electrolyte, which resulted in the facetted Ag nanowires shown in Figure 3b. In the previous work, it was shown that the interface anisotropy becomes stronger due to the field enhancement at the top of the hemispherical islands in an ultra-dilute electrolyte of low electrical conductivity [20]. Third, planar growth on one of the facet planes was initiated and planar nanostructure grew further, forming a facetted nanosheet (Figure 3c). The nanosheets, which were attached to the facetted nanowires, grew wider (up to approximately 10 μm) with increasing deposition time, as shown in Figure 3d. Figure 3e shows the enlarged top-view SEM image of the nanosheet on the specimen shown in Figure 3c. The growth of hexagonal nanosheet can be described, as shown in Figure 3f. After the planar growth (i) on one facet plane of the facetted nanowire, another planar growth occurs on the other facet plane (ii), as shown in Figure 3e. The nanosheet grows further with deposition time and finally forms a hexagonal nanostructure (iv).