title: Gibbs-Thomson Effect in Planar Nanowires: Orientation and Doping Modulated Growth.
abstract: Epitaxy-enabled bottom-up synthesis of self-assembled planar nanowires via the vapor-liquid-solid mechanism is an emerging and promising approach toward large-scale direct integration of nanowire-based devices without postgrowth alignment. Here, by examining large assemblies of indium tin oxide nanowires on yttria-stabilized zirconia substrate, we demonstrate for the first time that the growth dynamics of planar nanowires follows a modified version of the Gibbs-Thomson mechanism, which has been known for the past decades to govern the correlations between thermodynamic supersaturation, growth speed, and nanowire morphology. Furthermore, the substrate orientation strongly influences the growth characteristics of epitaxial planar nanowires as opposed to impact at only the initial nucleation stage in the growth of vertical nanowires. The rich nanowire morphology can be described by a surface-energy-dependent growth model within the Gibbs-Thomson framework, which is further modulated by the tin doping concentration. Our experiments also reveal that the cutoff nanowire diameter depends on the substrate orientation and decreases with increasing tin doping concentration. These results enable a deeper understanding and control over the growth of planar nanowires, and the insights will help advance the fabrication of self-assembled nanowire devices.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore.
authors.forename: Youde
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Electrical and Computer Engineering, University of California San Diego , La Jolla, California 92093, United States.
authors.forename: Renjie
authors.initials: R
authors.lastname: Chen
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798 Singapore.
authors.forename: Xuechao
authors.initials: X
authors.lastname: Yu
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798 Singapore.
authors.forename: Qijie
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Center for Integrated Nanotechnologies, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Jungjohann
authors.affiliation: Department of Electrical and Computer Engineering, University of California San Diego , La Jolla, California 92093, United States.
authors.forename: Shadi A
authors.initials: SA
authors.lastname: Dayeh
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955, Saudi Arabia.
authors.forename: Tom
authors.initials: T
authors.lastname: Wu
keywords: Gibbs−Thomson effect; ITO; In2O3; nanowire; surface energy; vapor−liquid−solid mechanism