Liquid-Assisted Vapor-Solid-Solid Silicon Nanowire Growth Mechanism Revealed by In Situ TEM When Using Cu-Sn Bimetallic Catalysts

We report on a silicon nanowire growth method that is based on the use of a dual-phase catalyst made of liquid Sn and solid Cu3Si, which results in a liquid-assisted VSS (LA-VSS) mechanism. The silicon atoms are brought by atomic hydrogen-assisted dissociation of silane molecules. We observe the growth in situ, in the transmission electron microscope, at atomic resolution. We show that the dual-phase catalyst favors the < 111 > crystallographic orientation. Each new Si(111) plane nucleates at the interface between the liquid and solid parts of the catalyst before propagating rapidly along the interface of Si top facet with the liquid part and slowly along the interface with the solid part. Moreover, we show that the structural properties of the Si nanowires, such as the growth direction and the twin density, can be controlled by adjusting the Sn/Cu ratio.

Automated summary

This study introduces a silicon nanowire growth method using a dual-phase catalyst of liquid Sn and solid Cu3Si, resulting in a liquid-assisted VSS mechanism. The growth process is observed in situ at atomic resolution. The structural properties of the Si nanowires, such as growth direction and twin density, can be controlled by adjusting the Sn/Cu ratio.