Isik, Muhammet AyhanCelik, KardelenCaglar, Mehtap AygunTurgut, Guven2026-03-262026-03-2620252452-262710.1016/j.flatc.2024.1007962-s2.0-85211707143https://doi.org/10.1016/j.flatc.2024.100796https://hdl.handle.net/20.500.14901/2499Aygün Çağlar, Mehtap/0000-0003-2860-0908Two-dimensional (2D) monolayer tungsten diselenide (WSe2) is of great interest in optoelectronic and photo (electro)catalytic applications due to its direct optical band gap characteristic which is highly dependent on the number of layers. Achieving uniform, high-purity, large-area monolayer WSe2 with the traditional salt-assisted chemical vapor deposition method (CVD) remains challenging due to the issues controlling the growth mechanisms and number of layers. Recent studies have demonstrated that metal vapor-assisted CVD can achieve uniform development of large-scale WSe2 monolayers. It is critical to comprehensively examine the influence of metal vapor-assisted CVD parameters on lateral WSe2 growth relative to salt-assisted CVD and to analyze the underlying mechanisms. Here, we carried out a systematic and comparable study assessing the effect of several CVD parameters on lateral WSe2 monolayer growth in the presence of a NaCl and an Au vapor catalyst, respectively. Detailed characterization of the grown WSe2 materials confirmed that using only a gold vapor catalyst in a confined micro-reactor space of sapphires allows for the ultrafast growth of highly crystalline, uniform, and sub-centimeter-sized monolayer WSe2 films without any residual ions, which can be scalable for reliable high-performance device fabrication and photocatalytic applications. Moreover, we observed that in-situ etching could occur on the film by the increased reaction time. Overall, this study paves the way for future research on fabricating large-area monolayer transition metal dichalcogenides and reaction mechanisms using gold or other metal vapor-assisted CVD in a confined reaction environment.eninfo:eu-repo/semantics/closedAccessTwo-Dimensional MaterialsTungsten Diselenide (WSe2)Micro-Reactor SpaceLateral GrowthArticle