Spectroscopy,Electrical And Optoelectronic Research Of 2D Materials

Two-dimensional layered materials are popular new materials in recent years.The new materials on the one hand can be studied through theoretical calculation,but on the other hand we need experimental research.Exploring the band structure of the materials is an important purpose of the experimental research and also the basis for studying other physical properties.Besides,using the material as the conductive channel of the device and measuring its electrical and optoelectronic properties can be a preliminary understanding of application prospects of the materials in the electronics and optoelectronics areas.In this paper,the band structure of graphene,black phosphorus and monolayer molybdenum disulfide was studied by spectroscopy.Fourier transform infrared spectroscopy?FTIR?was used to measure the extinction spectra of graphene in the far-infrared band and the transmission spectra of black phosphorus in the mid-infrared band.The photoluminescence spectra and excitation spectra of monolayer molybdenum disulfide were also measured using femtosecond laser.Measurements show that graphene absorbs much of far-infrared light,and the smaller wave number,the more absorption.The absorption of 100 cm^-11 light exceeds 20%.The mid-infrared transmission spectrum of black phosphorus is anisotropy,and the absorption of light is significant when the wave number of the light is greater than 2400 cm^-1 and nonsignificant on the contrary.The bandgap of the bulk black phosphorus is about 0.3 eV.Back-gate field effect transistors are fabricated using 8 nm thick black phosphorus,and they exhibit bipolar conductivity.The hole mobility of the transistors can be 67 cm²/?V?s?,and their photoresponsivity versus optical powers show a negative exponential relationship.The photoluminescence spectra of monolayer molybdenum disulfide has two peaks,which can be interpreted by a split of its valence band,and the relationship between its band gap and temperature satisfies the Varshni equation.