Growth of vertically aligned nanowires in metal–oxide nanocomposites: kinetic Monte-Carlo modeling versus experiments

Abstract

We employ kinetic Monte-Carlo simulations to study the growth process of metal-oxide nanocomposites obtained via sequential pulsed laser deposition. Using Ni-SrTiO3 (Ni-STO) as a model system, we reduce the complexity of the computational problem by choosing a coarse-grained approach mapping Sr, Ti and O atoms onto a single effective STO pseudo-atom species. With this ansatz, we scrutinize the kinetics of the sequential synthesis process, governed by alternating deposition and relaxation steps, and analyze the self-organization propensity of Ni atoms into straight vertically aligned nanowires embedded in the surrounding STO matrix. We finally compare the predictions of our binary toy model with experiments and demonstrate that our computational approach captures fundamental aspects of self-assembled nanowire synthesis. Despite its simplicity, our modeling strategy successfully describes the impact of relevant parameters like the concentration or laser frequency on the final nanoarchitecture of metal-oxide thin films grown via pulsed laser deposition.

Phase separation and surface segregation in Co–Au–SrTiO3 thin films: Self-assembly of bilayered epitaxial nanocolumnar composites

“…To identify the key mechanisms governing selforganization in three phase composites, it is helpful to recall earlier theoretical work on self-assembly of nanocolumnar thin films [16,28]. During high temperature sequential PLD growth of metal-oxide composites, metal atoms deposited at the surface diffuse and aggregate into clusters which eventually evolve into thermodynamically stable islands.…”

“…Stacking of islands in consecutive steps gives rise to rods and nanowires, whose diameter and density will depend on the synthesis parameters like temperature, concentration and deposition rate [16]. It is important to stress that, in order to achieve a thorough description of the synthesis process, even in monometallic systems, vertical diffusion steps (in a direction perpendicular to the thin film surface) have to be explicitely taken into account [16]. This vertical mobility is a key ingredient required to understand the synthesis of immiscible multiphase systems.…”

“…In recent years, a novel approach based on nanoscale self-organization of metallic nanostructures embedded in various single-crystal oxide systems has been established, which allows to bridge the gap between epitaxy and shape tuning. Nanocolumnar composites consisting of elemental Fe, Ni, Co, Au, Pt, Ir nanowires epitaxied in different matrices such as SrTiO 3 , BaTiO 3 , BaZrO 3 , or CeO 2 were successfully grown [10][11][12][13][14][15][16]. While the synthesis of nanowires consisting of miscible metals was also demonstrated [17,18], results on systems with formation of more than two phases are scarce.…”

Structural and Magnetic Characteristics of Ferrum Nanotubes Obtained at Different Potentials of Electrodeposition

“…1D metallic nanostructures (NS), such as nanotubes (NTs) and nanowires (NWs), are in great interest in scientific world due to their high potential of application in nanosize devises and sensors . Arrays with equal size and 1D NS shape are in perspective for manufacturing different functional nanodevices on their basis . In practical use, tubural structures can successfully replace not only NWs, but also nanoparticles, in such fields like catalysis, sensory, and bio applications, because of the significant increased surface area …”

“…[1][2][3] Arrays with equal size and 1D NS shape are in perspective for manufacturing different functional nanodevices on their basis. [4][5][6][7] In practical use, tubural structures can successfully replace not only NWs, but also nanoparticles, in such fields like catalysis, sensory, and bio applications, because of the significant increased surface area. [8][9][10][11][12][13] The actively used method for producing metallic NTs is a template synthesis.…”