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Manipulating the Dynamics of Self-Propelled Gallium Droplets by Gold Nanoparticles and Nanoscale Surface Morphology

Zakharov, Alexei LU ; Mårsell, Erik LU ; Hilner, Emelie LU ; Timm, Rainer LU ; Andersen, Jesper N.; Lundgren, Edvin LU and Mikkelsen, Anders LU (2015) In ACS Nano 9(5). p.5422-5431
Abstract
Using in situ surface-sensitive electron microscopy performed in real time, we show that the dynamics of micron-sized Ga droplets on Ga P(111) can be manipulated locally using Au nanoparticles. Detailed measurements of structure and dynamics of the surface from microns to atomic scale are done using both surface electron and scanning probe microscopies. Imaging is done simultaneously on areas with and without Au particles and on samples spanning an order of magnitude in particle coverages. Based on this, we establish the equations of motion that can generally describe the Ga droplet dynamics, taking into account three general features: the affinity of Ga droplets to cover steps and rough structures on the surface, the evaporation-driven... (More)
Using in situ surface-sensitive electron microscopy performed in real time, we show that the dynamics of micron-sized Ga droplets on Ga P(111) can be manipulated locally using Au nanoparticles. Detailed measurements of structure and dynamics of the surface from microns to atomic scale are done using both surface electron and scanning probe microscopies. Imaging is done simultaneously on areas with and without Au particles and on samples spanning an order of magnitude in particle coverages. Based on this, we establish the equations of motion that can generally describe the Ga droplet dynamics, taking into account three general features: the affinity of Ga droplets to cover steps and rough structures on the surface, the evaporation-driven transition of the surface nanoscale morphology from rough to flat, and the enhanced evaporation due to Ga droplets and Au nanoparticles. Separately, these features can induce either self-propelled random motion or directional motion, but in combination, the self-propelled motion acts to increase the directional motion even if the directional force is 100 times weaker than the random force. We then find that the Au particles initiate a faster native oxide desorption and speed up the rough to flat surface transition in their vicinity. This changes the balance of forces on the Ga droplets near the Au particles, effectively deflecting the droplets from these areas. The model is experimentally verified for the present materials system, but due to its very general assumptions, it could also be relevant for the many other materials systems that display self-propelled random motion. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
droplets, controlled self-propelled motion, III-V semiconductor, SPELEEM, SPM
in
ACS Nano
volume
9
issue
5
pages
5422 - 5431
publisher
The American Chemical Society
external identifiers
  • wos:000355383000078
  • scopus:84930614494
ISSN
1936-086X
DOI
10.1021/acsnano.5b01228
language
English
LU publication?
yes
id
92f79f5a-ecd1-4c13-a0de-bc6e2f0fdbc8 (old id 7613615)
date added to LUP
2015-07-21 13:43:47
date last changed
2017-05-28 03:17:36
@article{92f79f5a-ecd1-4c13-a0de-bc6e2f0fdbc8,
  abstract     = {Using in situ surface-sensitive electron microscopy performed in real time, we show that the dynamics of micron-sized Ga droplets on Ga P(111) can be manipulated locally using Au nanoparticles. Detailed measurements of structure and dynamics of the surface from microns to atomic scale are done using both surface electron and scanning probe microscopies. Imaging is done simultaneously on areas with and without Au particles and on samples spanning an order of magnitude in particle coverages. Based on this, we establish the equations of motion that can generally describe the Ga droplet dynamics, taking into account three general features: the affinity of Ga droplets to cover steps and rough structures on the surface, the evaporation-driven transition of the surface nanoscale morphology from rough to flat, and the enhanced evaporation due to Ga droplets and Au nanoparticles. Separately, these features can induce either self-propelled random motion or directional motion, but in combination, the self-propelled motion acts to increase the directional motion even if the directional force is 100 times weaker than the random force. We then find that the Au particles initiate a faster native oxide desorption and speed up the rough to flat surface transition in their vicinity. This changes the balance of forces on the Ga droplets near the Au particles, effectively deflecting the droplets from these areas. The model is experimentally verified for the present materials system, but due to its very general assumptions, it could also be relevant for the many other materials systems that display self-propelled random motion.},
  author       = {Zakharov, Alexei and Mårsell, Erik and Hilner, Emelie and Timm, Rainer and Andersen, Jesper N. and Lundgren, Edvin and Mikkelsen, Anders},
  issn         = {1936-086X},
  keyword      = {droplets,controlled self-propelled motion,III-V semiconductor,SPELEEM,SPM},
  language     = {eng},
  number       = {5},
  pages        = {5422--5431},
  publisher    = {The American Chemical Society},
  series       = {ACS Nano},
  title        = {Manipulating the Dynamics of Self-Propelled Gallium Droplets by Gold Nanoparticles and Nanoscale Surface Morphology},
  url          = {http://dx.doi.org/10.1021/acsnano.5b01228},
  volume       = {9},
  year         = {2015},
}