Dynamic growth/etching model for the synthesis of two-dimensional transition metal dichalcogenides via chemical vapour deposition

The preparation of two-dimensional transition metal dichalcogenides on an industrially relevant scale will rely heavily bottom-up methods such as chemical vapour deposition. In order to obtain sufficiently large quantities high-quality material, a knowledge-based optimization strategy for the synthesis process must be developed. A major problem that has not yet been considered is degradation materials by etching during due high growth temperatures. To address this problem, we introduce mathematical model accounts both and, first time, describe dichalcogenides. We consider several experimental observations lead differential equation based terms corresponding different supply mechanisms, describing time-dependent change in flake size. By solving and fitting two independently obtained data sets, find area leading term our model. show can solved analytically when only considered, solution provides general description complex shrinkage phenomena. Physically, dominance suggests material via itself contributes most its net growth. This finding also implies predominant interplay between insertion release atoms their motion form highly dynamic within flake. contrast previous assumptions, edges do play important role actual size dichalcogenide flakes