Growth Dynamics of Gallium Nanodroplets Driven by Thermally Activated Surface Diffusion

Zhaslan Baraissov; Federico Panciera; Laurent Travers; Jean-Christophe Harmand; Utkur Mirsaidov

doi:10.1021/acs.jpclett.9b01563

Growth Dynamics of Gallium Nanodroplets Driven by Thermally Activated Surface Diffusion

J Phys Chem Lett. 2019 Sep 5;10(17):5082-5089. doi: 10.1021/acs.jpclett.9b01563. Epub 2019 Aug 21.

Authors

Zhaslan Baraissov^{1

2}, Federico Panciera^{1

2

3}, Laurent Travers³, Jean-Christophe Harmand³, Utkur Mirsaidov^{1

2

4

5}

Affiliations

¹ Department of Physics, National University of Singapore, Singapore 117551, Singapore.
² Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore 117557, Singapore.
³ Centre for Nanoscience and Nanotechnology, CNRS, Université Paris-Sud, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France.
⁴ Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore.
⁵ Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.

PMID: 31403800
DOI: 10.1021/acs.jpclett.9b01563

Abstract

The growth of catalytic liquid-metal nanodroplets on flat substrates is essential for many technological applications. However, the detailed nucleation and growth dynamics of these nanodroplets remain unclear. Here, using in situ transmission electron microscopy (TEM) imaging, we track in real time the growth of individual Ga nanodroplets from a beam of Ga vapor. We show that the nucleation and growth are driven by thermally activated surface diffusion of Ga adatoms, with the diffusion activation energy of E_D = 95 ± 10 meV on a SiN_x surface. More importantly, our analysis shows that Ga dimers serve as the critical nucleation clusters and that the nanodroplet growth follows a power-law of the form R(t) ∝ e^-E_D/k_BT(t - t₀)^1/2. These insights into the growth dynamics of metallic nanodroplets are essential for tailoring their size and density for their application in self-catalyzed growth of nanomaterials.