Exploring the Dynamics of Sn Droplets on Hydrogenated Amorphous Si and Ge Layers for Nanocrystal Design

Studying the interaction between metal droplets and amorphous layers can unlock the potential to nanocrystal design, enhance material properties, and provide fundamental knowledge. With the help of plasma-enhanced chemical vapor deposition (PECVD), this work explores the interplay between Sn metal droplets and amorphous layers (Si and Ge) by investigating two growth modes: standard mode (amorphous layer on metal droplets) and inverted mode (metal droplets on an amorphous layer). Based on these modes, in-plane NWs fabricated from a variety of amorphous layer stacks including single layers, bilayers, and up to 10 layers are compared and discussed. We found that nanostructures are obtained only when Sn droplets can interact directly with an amorphous Ge layer in the inverted mode. A wide variety of nanocrystals including NWs, nanobelts, and nanopillars are obtained when using an amorphous multilayer stack. The results are discussed based on surface tension and interfacial diffusion phenomena.