Third-order Nonlinear Optical Properties Of Composite Films Based On Two-dimensional Materials

This thesis mainly adopts vacuum suction filter method,liquid phase stripping method and magnetron sputtering method to prepare graphene/MoS₂ and Ag/graphene/MoS₂ nanocomposite films.The morphology and structure of graphene/MoS₂ and Ag/graphene/MoS₂ nanocomposite films were characterized and analyzed by basic characterization methods.The linear and nonlinear optical properties of the samples were studied by UV-Vis spectrophotometer and femtosecond Z-scanning technique.By changing the sputtering conditions of magnetron sputtering,the influence of silver films on the optical properties of nanocomposite films under different sputtering conditions was studied.The main research results are as follows:Low-layers of MoS₂ and graphene were successfully prepared by liquid phase stripping method,and then graphene/MoS₂ nanocomposite films were successfully prepared by vacuum pumping filtration method.Ag nanofilms were prepared by magnetron sputtering at different sputtering power.With the increase of DC magnetron sputtering power,the diameter of Ag nanoparticles increased and became denser.By transferring the graphene/MoS2 nanocomposite film to the Ag nanofilm,the Ag/graphene/MoS2 nanocomposite films were successfully prepared.The linear absorption characteristics of the samples were measured by UV-Vis.It was found that the absorption of the prepared graphene/MoS₂ nanocomposite films was higher than that of graphene and MoS₂ nanofilms,and the absorption peaks were similar to those of MoS₂.Ag/graphene/MoS₂ nanocomposite films have a similar absorption peak to graphene/MoS₂ nanocomposite films,and with the increase of magnetron sputtering power of Ag,the absorption peak is red-shifted and the band gap decreases.The test results of femtosecond Z-scan technology show that the nonlinear absorption of graphene/MoS₂ nanocomposite films is superior to that of graphene and MoS₂ nanofilms,while the nonlinear absorption of Ag/graphene/MoS₂ nanocomposite film,which were obtained by Ag modification,is higher than that of graphene/MoS₂nanocomposite films.And with the increase of sputtering power of Ag,the saturation absorption of Ag/graphene/MoS₂ nanocomposite film is enhanced.Compared with single graphene and MoS₂ nanofilms,the nonlinear absorption of graphene/MoS₂ and Ag/graphene/MoS₂ nanocomposite films is 1-2 times improved,and the third-order nonlinear optical properties of Ag/graphene/MoS₂ nanocomposite films are superior to that of graphene/MoS₂ nanocomposite films.