Oxide mediated liquid–solid growth of high aspect ratio aligned gold silicide nanowires onSi(110) substrates

Abstract

Silicon nanowires grown using the vapor–liquid–solid method are promising candidates fornanoelectronics applications. The nanowires grow from an Au–Si catalyst during siliconchemical vapor deposition. In this paper, the effect of temperature, oxide at the interfaceand substrate orientation on the nucleation and growth kinetics during formation ofnanogold silicide structures is explained using an oxide mediated liquid–solidgrowth mechanism. Using real time in situ high temperature transmission electronmicroscopy (with 40 ms time resolution), we show the formation of high aspect ratio (≈15.0) aligned gold silicide nanorods in the presence of native oxide at the interface during in situannealing of gold thin films on Si(110) substrates. Steps observed in the growth rate andreal time electron diffraction show the existence of liquid Au–Si nano-alloy structures onthe surface besides the un-reacted gold nanostructures. These results might enable us toengineer the growth of nanowires and similar structures with an Au–Si alloy as a catalyst.