Preparation,Characterization And SaturableAbsorption Properties Of Two-Dimensional Transition Metal Sulfides

As a new type two-dimensional material,two-dimensional transition metal sulfides(TMDs)have attracted wide attention from researchers due to their unique layered structure and excellent photoelectric properties.In this paper,three transition metal sulfides,molybdenum disulfide(MoS2),molybdenum diselenide(MoSe2)and antimony disulfide(ReS2),were studied.Firstly,take molybdenum disulfide and molybdenum diselenide as the research objects,the basic properties and preparation methods of the materials were discussed.And molybdenum disulfide and molybdenum diselenide nanosheets were successfully exfoliated by ultrasonic assisted liquid phase exfoliation method(UALPE).The morphology and Raman spectra and absorption spectra of the materials were characterized.In order to apply the two-dimensional materials to the pulsed lasers,we transferred the two nanosheets dispersions onto a glass substrate by spin coating.And we studied the saturable absorption properties by Z-scan method.Finally we used them as saturable absorber into a solid-state 1 micron laser.A stable operation of pulsed laser was achieved.In addition,the two-dimensional material/semiconductor heterojunction was discussed in this paper.Take bismuth disulfide/GaAs(ReS2/GaAs)as research object,its controllable preparation and optical properties were systematically studied.The saturable absorber was used in a solid state laser at 1 micron.The specific work of this paper is as follows:1.Firstly,the research progress of two-dimensional materials at home and abroad was investigated.And the basic properties and application values of three two-dimensional materials(MoS2,MoSe2 and ReS2)appearing in the paper were introduced,as well as the two-dimensional material/semiconductor heterojunction.Finally,the common preparation methods and characterization methods of two-dimensional materials were introduced.2.Few-layer molybdenum disulfide and molybdenum diselenide were prepared by ultrasonic assisted liquid phase exfoliation method.The surface topography and thickness information of two two-dimensional materials were analyzed by Raman spectroscopy,transmission electron microscopy(TEM)and linear absorption spectroscopy.The saturable absorption characteristics of two two-dimensional materials in the 1 micron band were studied by the Z-scan method.3.As saturable absorbers,the prepared two-dimensional materials MoS2 and MoSe2 were inserted into the Nd:GdV04 solid-state laser.A stable Q-switched laser output was obtained.When MoS2 was used as the saturable absorber,a stable pulse output with a shortest pulse width of 261 ns,a repetition rate of 362 kHz,a peak power and single pulse energy of 1.27 W and 0.33 ?J,respectively,was obtained.When MoSe2 is used as the saturable absorber,a stable pulse output with a minimum pulse width of 217.5 ns,a repetition rate of 487.5 kHz,a peak power and single pulse energy of 1.65 W and 0.36?J,respectively,was obtained.Finally,the saturable absorption properties of the two two-dimensional nanomaterials were compared and analyzed.These experimental results confirmed the potential of two-dimensional transition metal sulfides as saturable absorbers.4.The preparation of semiconductor heterojunction structure ReS2/GaAs was realized.Take ReS2/GaAs as saturable absorber in Nd:YV04 solid state laser,a Q-switching operation was achieved.In addition,the Q-switching performance of ReS2/GaAs and the pure GaAs Q-switching performance were performed under the same condition.Comparative analysis showed that the heterojunction structure can effectively shorten the pulse width and obtain greater pulse energy and peak power.