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Semiconducting transition metal dichalcogenides (TMDs) are a specific class of two-dimensional (2D) materials with the chemical structure MX2. A transition metal, represented by “M”, is positioned between two chalcogen layers, represented by “X2”. The specific system of interest in this research is tungsten disulfide, WS2, which has applications in optoelectronics. This work focuses on synthesis of WS2 via chemical vapor deposition (CVD) using a liquid precursor. In this process, argon gas carries gas phase sulfur through a quartz tube. The Si substrate that has been plasma cleaned and spin coated with the liquid precursor is placed in the center of the tube furnace, downstream from the sulfur. The sulfur is usually heated to about 250 °C, while the furnace is heating to around 800 °C. The influence of growth parameters (such as growth time, gas flow rate, and temperature) on the crystallinity of these atomically thin layers is also studied. Raman spectroscopy and photoluminescence (PL) are non-invasive techniques that are commonly used to analyze TMDs. The epitaxial relation between both crystals will be studied along with variation in number of layers and optical fingerprint of the WS2. The choice of substrate is expected to change the properties of the sample. Thus, future work will investigate the growth of WS2 and Fe-WS2 on highly ordered pyrolytic graphite (HOPG).



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Optimization of Growth Parameters of WS2 Synthesis: Effects on Crystallinity and Optical Properties