Facile and Controllable Synthesis of Large-Area Monolayer WS2 Flakes Based on WO3 Precursor Drop-Casted Substrates by Chemical Vapor Deposition

摘要: Monolayer WS2 (Tungsten Disulfide) with a direct-energy gap and excellent photoluminescence quantum yield at room temperature shows potential applications in optoelectronics. However, controllable synthesis of large-area monolayer is still challenging because the difficulty controlling interrelated growth parameters. Herein, we report facile method for flakes by direct sulfurization powdered WO3 Trioxide) drop-casted on SiO2/Si substrates one-end sealed quartz tube. The samples were thoroughly characterized an optical microscope, atomic force transmission electron fluorescence spectrometer, Raman spectrometer. obtained results indicate that large triangular edge length up to 250 370 μm homogeneous crystallinity readily synthesized within 5 min growth. We demonstrate as-grown show distinctly size-dependent emission, which mainly attributed heterogeneous release intrinsic tensile strain after