Formation and morphological evolution of self-similar 3D nanostructures on weakly interacting substrates

作     者：B. Lü G. A. Almyras V. Gervilla J. E. Greene K. Sarakinos 

作者机构：Nanoscale Engineering Division Department of Physics Chemistry and Biology Linköping University SE 581 83 Linköping Sweden Thin Film Physics Division Department of Physics Chemistry and Biology Linköping University SE-581 83 Linköping Sweden Materials Science and Physics Departments University of Illinois Urbana Illinois 61801 USA 

出 版 物：《Physical Review Materials》 (Physic. Rev. Mat.)

年 卷 期：2018年第2卷第6期

页      面：063401-063401页

核心收录：

基　　金：Linköpings Universitet, LiU, (Dnr-LiU-2015-01510) Linköpings Universitet, LiU Knut och Alice Wallenbergs Stiftelse, (KAW 2011-0094) Knut och Alice Wallenbergs Stiftelse Vetenskapsrådet, VR, (VR-2011-5312, VR-2015-04630, VR2014-5790) Vetenskapsrådet, VR 

主　　题：Growth Island Nucleation on surfaces Surface diffusion Nanoparticles Thin films Metropolis algorithm Molecular dynamics 

摘      要：Vapor condensation on weakly interacting substrates leads to the formation of three-dimensional (3D) nanoscale islands (i.e., nanostructures). While it is widely accepted that this process is driven by minimization of the total film/substrate surface and interface energy, current film-growth theory cannot fully explain the atomic-scale mechanisms and pathways by which 3D island formation and morphological evolution occurs. Here, we use kinetic Monte Carlo simulations to describe the dynamic evolution of single-island shapes during deposition of Ag on weakly interacting substrates. The results show that 3D island shapes evolve in a self-similar manner, exhibiting a constant height-to-radius aspect ratio, which is a function of the growth temperature. Furthermore, our results reveal the following chain of atomic-scale events that lead to compact 3D island shapes: 3D nuclei are first formed due to facile adatom ascent at single-layer island steps, followed by the development of sidewall facets bounding the islands, which in turn facilitates upward diffusion from the base to the top of the islands. The limiting atomic process which determines the island height, for a given number of deposited atoms, is the temperature-dependent rate at which adatoms cross from sidewall facets to the island top. The overall findings of this study provide insights into the directed growth of metal nanostructures with controlled shapes on weakly interacting substrates, including two-dimensional crystals, for use in catalytic and nanoelectronic applications.