Structural and Optical Properties of Tungsten Disulfide Nanoscale Films Grown by Sulfurization from W and WO3

Abstract

Tungsten disulfide (WS2) was prepared from W metal and WO3 by ion beam sputtering and sulfurization in a different number of layers, including monolayer, bilayer, six-layer, and nine-layer. To obtain better crystallinity, the nine-layer of WS2 was also prepared from W metal and sulfurized in a furnace at different temperatures (800, 850, 900, and 950 °C). X-ray diffraction revealed that WS2 has a 2-H crystal structure and the crystallinity improved with increasing sulfurization temperature, while the crystallinity of WS2 sulfurized from WO3 (WS2-WO3) is better than that sulfurized from W-metal (WS2-W). Raman spectra show that the full-width at half maximum (FWHM) of WS2-WO3 is narrower than that of WS2-W. We demonstrate that high-quality monocrystalline WS2 thin films can be prepared at wafer scale by sulfurization of WO3. The photoluminescence of the WS2 monolayer is strongly enhanced and centered at 1.98 eV. The transmittance of the WS2 monolayer exceeds 80%, and the measured band gap is 1.9 eV, as shown by ultraviolet-visible-infrared spectroscopy.

Epitaxial Growth and Characterization of Nanoscale Magnetic Topological Insulators: Cr-Doped (Bi0.4Sb0.6)2Te3

“…The cell temperature was precisely adjusted prior to growth to achieve the desired flux, which was calibrated with a beam flux monitor (BFM). The substrate underwent the same cleaning process as described in our prior publication [ 27 , 28 , 29 ]. After cleaning, the sapphire substrate was inserted into the MBE chamber and then preheated at 1010 °C under 10 −9 Torr for 70 min.…”

Enhanced Photoelectrochemical Activity Realized from WS2 Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

“…The WS 2 can also be prepared by sulfurization of tungsten or tungsten oxide film. [38] However, controlling the sulfur content in this method is little tedious problematic. The preparation of WS 2 is also reported by the electrodeposition process, [39] but their tendency towards non-conformal growth on non-planar surfaces creates a disadvantage.…”

Efficient van der Waals layered gallium telluride-based passive photodetectors for low-power-density sensing of visible light

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