Unique dewetting growth of Si on Ag(111)

Naoya Kawakami^1*, Ryuichi Arafune², Emi Minamitani³, Noriaki Takagi⁴, Chun-Liang Lin¹

¹Electrophysics, National Yang Ming Chiao Tung university, Hsinchu, Taiwan
²National Institute for Materials Science, Tsukuba, Japan
³Institute for Molecular Science, Okazaki, Japan
⁴Kyoto university, Kyoto, Japan

* Presenter:Naoya Kawakami, email:kawakami@nctu.edu.tw

A honeycomb sheet of Si, namely silicene, has attracted much attention as a candidate material for electronic and spintronic devices. After the successful synthesis of silicene on Ag(111) [1], various characteristics of silicene have been clarified. However, there remain several questions still to be revealed. The growth behavior of silicene is one of the open questions. Although monolayer silicene wholly covers the substrate surface, further deposition of Si induces dewetting of silicene, even though the temperature is kept constant during the growth [2]. This growth mode is an exceptional case of epitaxial growth. We investigated the mechanism of the unique dewetting growth by combining experiments with scanning tunneling microscopy/spectroscopy (STM/S) and a simulation by kinetic Monte Carlo (KMC) method.
By considering the difference of the diffusion rate on each layer, the dewetting growth was well reproduced by the KMC simulation. It indicates that the variation in the diffusion condition strongly affects the growth of the crystal, sometimes resulting in unconventional growth behavior.

[1] B. Lalmi et al., Appl. Phys. Lett. 97, 223109 (2010).
[2] P. Moras et al., J. Phys.: Condens. Matter 26, 085001 (2014).

Keywords: STM, kinetic Monte Carlo, silicene