Controllable Synthesis Of Two-dimensional ZrS₃ Nanosheets And Explore Its Physicochemical Properties

In recent years,transition metal trisulfides（MX ₃）in low-dimensional materials have attracted extensive attention of researchers due to their unique chain-like structure,strong in-plane anisotropy,and novel physical and chemical properties.Zirconium trisulfide（ZrS₃）is a typical representative of MX₃,a p-type semiconductor with a wide photoresponsivity from ultraviolet（UV）to near-infrared（NIR）,which is widely used in electronic devices such as field effect transistors（FET）and ultraviolet photodetectors.However,there are few reports on the origin of the in-plane anisotropy of ZrS₃ and the interlayer coupling of the material,which is not conducive to further optimizing and improving the performance of ZrS ₃ electronic devices.The economical and efficient synthesis of large-area ZrS₃ films is the premise for ZrS₃ to move from laboratory to industrialization.At present,two-dimensional ZrS₃ nanosheets are mainly prepared by chemical vapor transport and liquid phase exfoliation,which is difficult to meet the needs of industrial production.Therefore,it is of great significance to explore a controllable and low-cost method to synthesis ZrS₃ nanosheets.The chemical vapor deposition to prepare two-dimensional materials has the advantages of controllability and low cost,and is recognized as a reliable way to prepare high-quality two-dimensional materials.In this paper,ZrS ₃ nanosheets were rapidly synthesized by chemical vapor deposition（CVD）using inexpensive ZrCl ₄powder and S powder as reaction precursors,and the effects of changing the reaction temperature and different substrates on the material morphology were explored.The morphology of the material and the crystallinity of the crystal were determined by optical microscopy,Raman,TEM.The crystal anisotropy and interlayer coupling of the material were determined by angle-dependent polarization Raman spectroscopy and temperature-variable Raman spectroscopy.Using ZrS₃ nanosheets as channel materials,FET were constructed to study their electrical properties.The Mo S ₂-ZrS₃heterojunction was constructed by dry transfer,and the optical properties of the heterojunction were tested.This work draws the following conclusions:（1）The morphology of ZrS₃ nanosheets synthesized by chemical vapor deposition is greatly affected by temperature.As the reaction temperature increased,the nucleation sites for zirconium trisulfide and the size of ZrS₃ nanosheets increased significantly.When the temperature is higher than 800℃,due to the influence of thermodynamic factors,ZrS₃is transferred into ZrS₂ nanosheets.Changing different growth substrates has no effect on the morphology of ZrS ₃ nanosheets,indicating that the growth of ZrS ₃nanosheets by chemical vapor deposition is not affected by the substrate.（2）XRD,HR-TEM and SAED prove that ZrS₃ nanosheets have good crystallinity and no impurities are generated during the reaction process;XPS,EDS and EDS mapping show that the material is composed of Zr and S,wit h a ratio of about 1:3,and the two elements are evenly distributed.（3）Through the angle polarization Raman spectrometer,we can see that the two largest intensities of the Raman peaks of A³g,A⁵g and A⁶g are displayed at 45°and 225°（b-axis direction）,indicating that the anisotropic ZrS ₃ nanosheets.The period is 180°.Through the temperature-variable Raman test,it was found that with the increase of temperature,the Raman peak frequencies of the three visible peaks A³g,A⁵g and A⁶g all showed obvious red shifts.According to the linear fitting,the first-order temperature coefficients of A_g³,A_g⁵ and A_g⁶ were-0.01870 cm^-1K^-1、-0.02315 cm^-1K^-1、-0.01191cm^-1K^-1,indicating the weak interlayer interaction of ZrS₃ nanosheets.（4）ZrS₃ nanosheets were used as channel materials to construct FET,which exhibited p-type semiconductor characteristics,and the carrier mobility is 7.53×10^-4 cm²V^-1s^-1.Monolayer MoS₂ was synthesized by chemical vapor deposition,and MoS₂-ZrS₃heterojunction was constructed by PDMS dry transfer method.The Raman spectral peaks and Raman mapping indicate that the heterojuntion has good van der Waals contact.