Manipulating the growth kinetics of vapor-liquid-solid propagated Ge nanowires

Abstract

This article describes an innovative approach in which bimetallic alloy seeds of AuxAg1–x are used to enhance the growth kinetics of Ge nanowires, via a vapor–liquid–solid (VLS) growth technique. The decreased equilibrium concentration and increased supersaturation of Ge in the liquid alloy seeds, compared to pure Au seeds, results in favorable growth kinetics and the realization of high-aspect ratio millimeter-long Ge nanowires. Also detailed is the manifestation of the Gibbs-Thompson effect resulting in diameter-dependent nanowire growth rates as a function of the Au–Ag–Ge eutectic composition. Significantly, AuxAg1–x alloy seeds lower the critical diameter of the Ge nanowires in this liquid-seeded growth approach. In situ TEM heating experiments established the correlation between the growth kinetics and equilibrium eutectic compositions in the ternary growth systems. The fundamental insights of nanowire growth demonstrated with the ternary eutectic alloys opens up opportunities to engineer the aspect ratio and morphology of a range of semiconductor nanowires.