Fabrication Of Two-dimensional Layered Tin Sulfide(SnS)and Its Applications

Since 2004,graphene has attracted many researchers'attention due to its excellent physical and chemical properties.As intrinsic graphene has no band gap,the research hotspots in recent years have gradually turned to hexagonal boron nitride(h-BN),transition metal chalcogenides(TMCs),group IV metal chalcogenides(GIVMCs)and black phosphorus.One type Group IV metal chalcogenide,tin sulfide(SnS),not only has the characteristics of abundant reserves,low price,environmental friendliness and good stability,but also is one of the few materials exhibiting P-type semiconductor properties in a natural state.However,the two-dimensional layered SnS prepared in recent years has a large thickness and a small size,which is difficult to be used for preparing micro-nano electronic devices.Therefore,it is particularly important to growth large-scale thin layer two-dimensional layered SnS and explore the fabrication and application of its components.This research focuses on three aspects of material growth,device fabrication and device application of two-dimensional layered SnS.The details are as follows:(1)Two-dimensional layered SnS growth study.Two-dimensional layered SnS is prepared by physical vapor deposition and chemical vapor deposition method,respectively.The characterizations of optical microscope(OM),scanning electron microscope(SEM),atomic force microscope(AFM),Raman spectroscopy(Raman),energy dispersive spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)confirm that the two-dimensional layered SnS prepared by the deposition method has high purity,good crystallinity,smooth surface,thickness of 25-95 nm and size of 2-6?m.The two-dimensional layered SnS prepared by physical vapor deposition has a thickness between 9-13 nm and a size larger than 5?m.(2)Fabrication of two-dimensional layered SnS-based components.Two-dimensional layered SnS based component is prepared by lithography pattern transfer method which is low cost,simple operation and small simple damage compared with optical etch method and electron beam exposure method The explored suitable mass fraction of the PMMA solution is 20%,and the rotational speed of the spin coating is 2000 rpm.The prepared device has a flat surface and good contact between the material and the electrode.(3)Application of two-dimensional layered SnS-based components study.The application of two-dimensional layered SnS-based components in field effect transistors and photodetectors is explored.The device has a hole mobility of 0.12 cm²V^-1s^-1and a switching ratio of about 8.2,which has the potential as a field effect transistor.Under different wavelengths of visible light illumination,the device has the highest responsivity to blue-violet light and can reach 156.0 AW^-1,the detectivity is 2.94×10¹⁰jones,the external quantum efficiency is 4.77×10⁴%,and the rise and fall times are 5.1 ms and 8.8 ms,respectively,which can be used as a visible light photodetector.Under 850 nm wavelength near-infrared light illumination,the responsivity of this devices can reach 1604 AW^-1,the external quantum efficiency is 2.34×10⁵%,the normalized detection is 3.42×10¹¹jones,the rise time?_ris 7.6 ms,and the fall time?_fis 29.9 ms,which can be used as flexible near-infrared photodetector.