Synthesis of Large-Area MoS2 Sword-Like Flakes by Chemical Vapor Deposition

Recently, the emerging field of two-dimensional materials is known to be promising due to their unique structure, special optical and electrical properties, and their applications in optoelectronic devices. In this paper, for the first time, we are reporting on new MoS
₂
samples with slightly different structures to that of the conventional ones. This is achieved using chemical vapor deposition (CVD) method and further changing of argon flux, furnace temperature, and precursors' distance to the location of substrates. This structure is sword-like, and it should be noted that length of some of these sword-like specimens is measured to be ≅700 micrometres. The broad dimensions of these samples may simplify the manufacturing process of the electronic components. The CVD reaction used here is carried out inside a furnace with one thermal zone and using sulfur and MoO3 as precursors. By changing the three effective growth parameters: argon flux, scraping the substrate surface (silicon oxide), and synthesis time, an optimum condition for the growth of the sword specimens is obtained. It is found that increasing argon flux up to a specific limit (200 SCCM), increases the length of the sword specimens, however, passing this limit, the length of the sword samples will stop increasing. Scratching the substrate's surface causes the sword-like specimens to accumulate in the scratched region. Furthermore, increasing the synthesis time results in the growth of more samples on the substrate's surface and creates a change in the samples crystalline form and transforms them into the fractal-like structure.