Investigation On Synthesis And Electrical Properties Of MoS_2xSe_2?1-x? Nanosheets

With the advent of the physical limit of traditional silicon-based devices,the integrated circuit industry urgently needs to find a new semiconductor material to get ridofthis problem.As a semiconductor compound with natural direct bandgap,molybdenum disulfide stands out from plenty of two-dimensional materials due to its excellent photoelectric properties.The key to the application of MoS₂ in the field of electronic devices is to optimize its properties and function.For this purpose,chemical doping of MoS₂ is an effective means.In this paper,atmosphere pressure chemical vapor deposition was used to synthesize MoS_2?1-x?Se_2x nanosheets and the growth mechanism was investigated in detail.After tuning deposition parameters such as growth temperature,source content and carrier flow,the shapes of MoS_2?1-x?Se_2x nanosheets are triangular or hexagonal shape under the optical microscopy and their average size is⁵0?m,the maximum size is more than 100?m.Atomic force microscope reveals that the thickness of the nanosheets is less than 2 nm,corresponding to monolayer to bilayer materials.In addition,MoS_2?1-x?Se_2xx with different selenium content can be obtained by controlling the amount of selenium powder.X-ray photoelectron spectroscopy is used to characterize the Se content in nanosheets and the mapping mode of Raman spectrum shows that selenium is evenly distributed in MoS_2?1-x?Se_2x.Characterizations of high-resolution transmission electron microscopy reveal that Se substitutions do not cause any serious damage and the MoS_2?1-x?Se_2xnanosheets have high crystallinity.The MoS_2?1-x?Se_2x nanosheet is utilized as channels to test its electrical properties in the field channel transistor.The voltage-current characteristics tested by the semiconductor parameter analyzer show that the MoS_2?1-x?Se_2x devices have the switching characteristic with¹0⁷ on-off ratio and their mobility is³.72 cm²V^-1s^-1.The introduction of selenium could modulate the bandgap of molybdenum disulfide.The successful growth of MoS_2?1-x?Se_2x nanosheets with controllable stoichiometry could empower a great deal of flexibility in designing atomically thin electronical and optoelectronic devices.