| Two-dimensional Mo S2 thin film is a kind of semiconductor material with excellent photoelectric properties,which has great application prospect in photoelectric detection,photoelectric conversion and photoelectric sensing.At present,the photoelectric application of Mo S2 film is mainly limited by two points.One is that it is difficult to achieve large-scale and controllable preparation of Mo S2 film,and the other is the lack of systematic research on the photoelectric properties of Mo S2 film with different layers.In this work,Chemical Vapor Deposition（CVD）process was used to explore the growth mechanism and layer number control approach of two-dimensional Mo S2 film on sapphire substrate,and the controllable layer number growth of two-dimensional Mo S2 film was realized.A simple photoelectric device was prepared by magnetron sputtering to prepare metal electrode on the surface of Mo S2 film.The photoelectric properties of Mo S2 film with different layers were tested,and the photoelectric properties were optimized by annealing and H2O2 chemical activation treatment.Experimental results show that compared with atmospheric CVD method,it is easier to obtain Mo S2 film under low pressure CVD condition.Under the condition of constant reaction pressure and temperature rise curve,the decrease of the distance between substrate and Mo source（source base distance）will increase the partial pressure PMo S2 of Mo S2 in atmospheric phase,and the decrease of the amount of Mo source will decrease the PMo S2.PMo S2 can be precisely regulated by adjusting the base distance and the amount of Mo source,and the growth of Mo S2 film with different layers can be realized.The high quality monolayer Mo S2 film was successfully prepared.Its Raman characteristic peak difference is 19.76 cm-1 and PL spectral characteristic peak intensity is high,showing obvious monolayer Mo S2 characteristics.At the same time,the preparation process and internal mechanism of double,three,four and multilayer Mo S2 films are mastered.The photoelectric performance of Mo S2 film was tested,and the experimental results show that:（1）For the same thickness of Mo S2 film,its photoelectric response to uv light is the best,and for the same light source,the smaller the thickness of Mo S2film photoelectric performance is better,single layer Mo S2 film for UV light has the best photoelectric characteristics,its sensitivity is 34.68,but the response time reaches the longest 46.0 s.（2）For monolayer and bilayer Mo S2 films,the saturation photocurrent of Mo S2 films can be improved by annealing at 800℃for one hour in sulfur atmosphere.After annealing,the uv sensitivity of monolayer Mo S2 films reaches 27.74,and the response time is shortened to 5.0 s.（3）For the bias and optical power,the saturation photocurrent of Mo S2film will increase with the increase of the bias,but with the number of photocarriers reached saturation,its increase is smaller and smaller.As the optical power density increases,the saturation photocurrent of Mo S2changes linearly with the optical power density in the range of 2-10 m W.（4）Mo S2 was treated with H2O2.With the increase of H2O2 treatment time on Mo S2 film,the saturation photocurrent of Mo S2 film increased significantly,and the response time also decreased significantly.Mo S2 film treated for 40 s had the best photoelectric performance,and the response reached 0.0357m A/W.The response time is only 4.5 s,while the film treated for 60 s has the best sensitivity of 313.06.In this work,we have mastered the internal mechanism and influence law of preparing Mo S2 film by CVD method,realized the layer control of Mo S2film growth,tested the photoelectric property of Mo S2 film with different layers,and explored the influence law of sulfur atmosphere annealing and H2O2chemical activation treatment on the photoelectric property of Mo S2 film.The results can provide experimental guidance for the mass preparation of large area Mo S2 thin film,and have certain reference value for the application of Mo S2thin film in the photoelectric field. |
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