Systematic study of CVD-growth parameters in NaCl-assisted growth of MoSe2 nanostructures: nanoribbons, dendrites and spirals

Abstract

MoSe₂, a two-dimensional (2D) transition metal dichalcogenide (TMDC), has garnered significant interest in recent years due to its semiconducting properties and tunable band gap with potential applications in optoelectronics, photocatalysis and atomically thin devices. In this study, we report the controlled synthesis of MoSe₂ nanocrystals using a custom 12-zone atmospheric pressure chemical vapour deposition (APCVD) system. NaCl is used as a seed promoter to facilitate the growth of monolayer, bilayer, and multilayer films, often as large as 200 μm. Additionally, the morphological evolution of the MoSe₂ nanostructures is controlled by tuning different growth parameters based on insights, which we discuss in detail. The growth of dominant nanostructures, which include nanoribbons, snowflakes, monolayers and multilayer domains, among others, are discussed. High-resolution optical microscopy, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to image the as-grown crystals. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) are used to verify the quality and elemental composition of our as-grown MoSe₂ crystals. Our findings brighten the prospect of growing novel 1D and 2D TMDC nanostructures with sufficient control to make them suitable for advanced optoelectronic and catalytic devices.