Morphological stabilization and KPZ scaling by electrochemically induced co-deposition of nanostructured NiW alloy films

Abstract

We have assessed the stabilizing role that induced co-deposition has in the growth of nanostructured NiW alloy films by electrodeposition on polished steel substrates, under pulsed galvanostatic conditions. We have compared the kinetic roughening properties of NiW films with those of Ni films deposited under the same conditions, as assessed by Atomic Force Microscopy. The surface morphologies of both systems are super-rough at short times, but differ at long times: while a cauliflower-like structure dominates for Ni, the surfaces of NiW films display a nodular morphology consistent with more stable, conformal growth, whose height fluctuations are in the Kardar-Parisi-Zhang universality class of rough two-dimensional interfaces. These differences are explained by the mechanisms controlling surface growth in each case: mass transport through the electrolyte (Ni) and attachment of the incoming species to the growing interface (NiW). Thus, the long-time conformal growth regime is characteristic of electrochemical induced co-deposition under current conditions in which surface kinetics is hindered due to a complex reaction mechanism. These results agree with a theoretical model of surface growth in diffusion-limited systems, in which the key parameter is the relative importance of mass transport with respect to the kinetics of the attachment reaction.

Protein Adsorption at Nanorough Titanium Oxide Surfaces: The Importance of Surface Statistical Parameters beyond Surface Roughness

“…A more detailed description of a given surface thus needs to consider also other, higher-order moments or even the full power spectrum [ 33 ]. Indeed, a few recent studies have shown that the physical behavior of rough surfaces, for instance during thin film deposition, depends non-trivially on higher-order moments of the surface height distribution such as surface skewness ( Ssk ) and kurtosis ( Sku ), which thus need to be carefully characterized in detail [ 34 , 35 , 36 ].…”

Surface super-roughening driven by spatiotemporally correlated noise

“…This leads to the existence of an independent local roughness exponent α loc that characterizes the local interface fluctuations and differs from the global roughness exponent α obtained by, for instance, the global width. This phenomenon is referred to as anomalous roughening and has received much attention in the last few years because its commonness in experiments [9][10][11][12][13][14][15][16][17][18][19][20][21]. Current theoretical knowledge has firmly established [22] that, indeed, the existence of power-law scaling of the correlation functions (i.e., scale invariance) does not determine a unique dynamic scaling form of the correlation functions.…”

The Fractal Geometry of Growth: Fluctuation–Dissipation Theorem and Hidden Symmetry

“…. , we compare this value with experiments in electrochemically induced co-deposition of nanostructured NiW alloy films, z 1.6 (2) [70], dynamics in chemical vapor deposition in silica films, z 1.6 (1) [71], on semiconductor polymer deposition z 1.61 (5) [6], and in excess of mutational jackpot events in expanding populations revealed by spatial Luria-Delbrück experiments, z 1.61 [72]. Thus, we have an agreement with different kinds of recent experiments, and very precise simulations [53], it is unlikely to be just a numerical coincidence.…”