| Abstract Scope |
Nucleation and growth of crystals involves a complex interplay of material thermodynamics and kinetics of bulk and surface mass transport and possibly chemical reactions. Thin crystalline solids (thin films, two-dimensional layered materials, nanowires, etc.) are commonly grown from vapor phase on solid substrates. Rheotaxy is a phenomenon where the growth of crystals occurs on liquid surfaces. The use of molten surfaces can, in principle, reduce interactions between the depositing species and the supporting substrate and hence can promote high-quality crystal growth.
Here, we compare and contrast rheotaxy with vapor-liquid-solid (VLS) process of the growth of crystalline solids under molten metal or metallic alloys. We present in situ scanning electron microscopy (SEM) studies of graphene growth from vapor phase using ethylene on molten gold. All of our experiments are carried out using a specially designed µReactor [1] in a SEM fitted with gas dosing capabilities. From real-time observations of the graphene growth as a function of ethylene flux, temperature, and time, we identify the factors underlying the nucleation and growth of graphene on molten gold surfaces. |