Fig. 3
From: Surface diffusion-limited lifetime of silver and copper nanofilaments in resistive switching devices
Morphological changes induced by surface diffusion. a Simulation results of the surface diffusion equations, indicating the rearrangement of a Ag CF with initial diameter d0 = 2 nm at increasing times, namely t = 0, 24 ms, 30 ms, and 60 ms. b Same as a, but for a CF with an initial diameter d0 = 0.4 nm at times t = 0, 40 μs, 0.13 ms, 0.4 ms, 0.6 ms, and 1 ms. For both cases, the CF length is 10 nm, equivalent to the thickness of the insulating layer between two planar electrodes. The color in the figures indicates the surface curvature, where surface points with higher curvature are more likely to induce surface diffusion, thus providing a suitable spot for CF rupture. The CF lifetime decreases from around 20 ms (a) to about 0.13 ms (b) as d0 is reduced from 2 nm to 0.4 nm. The ovulation effect in b, where nano-clusters result from the disconnection of a thin CF, is consistent with in situ TEM observations of Ag nano-clusters evolving from Ag nanoscale CFs17,26,34
