CVD growth of molybdenum diselenide surface structures with tailored morphology

Abstract

Controllable atmospheric pressure CVD has been optimized to grow transition metal dichalcogenide MoSe₂ with tunable morphology at 750 °C on a silicon substrate with a native oxide layer of 250 nm. Utilizing tetrapotassium perylene-3,4,9,10-tetracarboxylate (PTAS) as a seed promoter and varying the vertical distance between the substrate and the precursor MoO₃, different morphologies of MoSe₂ were achieved, including 2D triangles, hexagons, 3D pyramids and vertically aligned MoSe₂ sheets. We find that the shape of MoSe₂ is highly dependent upon the distance h between the substrate and the precursor. The change in the morphology is attributed to the confinement of vapor (MoO₃ and Se) precursors and their concentrations due to the change in h. These results are helpful in improving our understanding about the factors which influence the morphology (shape evolution) and also the continuous growth of MoSe₂ films.