Solid-state dewetting of magnetic binary alloy thin films and application as nanowire and nanotube growth catalysts.

Abstract

Dewetting is a simple and low-cost method to fabricate nanoparticles. We examined solid-state dewetting behavior of miscible (CoPd) and immiscible (CoAu) magnetic alloy thin films by annealing below their melting temperatures. We found that CoPd and CoAu dewetting stages follow that of elemental materials. We established that CoPd alloy morphology and dewetting rate lie in between its parent materials. Johnson-Mehl-Avrami (JMA) analysis was utilized to extract dewetting activation energy of CoPd alloy. For CoAu alloy, Au-rich particles and Co-rich particles are distinguishable and we are able to predict the interparticle spacings and particle densities for the particles which agree well with the experimental results. We characterized the magnetic properties of CoPd and CoAu nanoparticles and explored the application of CoPd and Pd nanoparticles as catalyst for SiO2 nanowires and nanotubes growth. The nanowires and nanotubes grow via VLS or VSS mechanism without using external Si source.