# 液相前驱体制备单层MoS2薄膜Preparation of Monolayer MoS2 Film from Liquid Precursor

Abstract: MoS2 film growth is mainly prepared by chemical vapor deposition (CVD). In this paper, liquid metal precursors are used to replace traditional powder materials, which effectively control the nucleation density on the growth substrate surface and improve the uniformity of the substrate surface sample. And the substrate pretreatment process, reaction temperature and time, air pressure, precursor volume and substrate stack structure in the growth process were systematically studied. By optimizing the preparation process, the controllable preparation of mono-layer, single-crystal MoS2 films was realized, and the single-crystal domain size reached 30 μm.

1. 引言

2. 实验

3. 结果与分析

Figure 1. Optical microscope images of ammonium molybdate aqueous solutions of different concentrations after the reaction. (A)~(H) The concentration of ammonium molybdate aqueous solution is 10, 2, 1, 0.8, 0.6, 0.4, 0.2, 0.02 mg/mL, respectively. (I) Statistical histograms of domain size in Figures (A)~(H). The scale in the figure is: 20 μm

Figure 2. Optical microscope images of the homogenizer after the reaction at different speeds. (A)~(D) Set the low speed of the homogenizer to 500 r/min, 10 s; set the high-speed gradient to 1000, 3000, 5000, 7000 r/min, 60 s. I) Statistical histograms of domain size in Figures (A)~(D) The scale in the figure is: 20 μm

Figure 3. (A) Schematic diagram of the relative positions of the spin-coated ammonium molybdate liquid precursor and the blank substrate. (B) An optical microscope picture of a sample on the surface of the substrate without a spatially confined structure. (C) An optical microscope picture of a sample on the surface of the substrate when the two substrates are 1 mm apart. The scale in the figure is: 20 μm

Figure 4. (A) Raman spectrum of MoS2 film. (B) TEM high-resolution image of MoS2 film, select the center area and enlarge it further, as shown by the black arrow. (C) Selected TEM electron diffraction pattern of MoS2 film

Figure 5. Electrical test curve of a mono-layer MoS2 transistor. (A) Output curve. (B) Transfer curve

4. 结论

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