| Single-layer molybdenum sulfide is very similar to graphene in the characteristics of high strength and good electrical conductivity. Most importantly, it has a band gap of 1.8 eV, making itself have potential application in photoelectric device and logic circuit. In this paper, we utilized the hydrothermal method coupling MoS2 and graphene together to get the heterojunction of MoS2/RGO. Aiming to use the large surface electronic transport corridor to improve the carrier mobility, to further promote the separation of electrons and holes in molybdenum sulfide layers under the light conditions, so as to improve the photoelectric properties. In order to research the different technological conditions (such as reaction temperature, hydrothermal time, GO mass) influencing on the morphology of samples, we use a variety of characterization method, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction and Raman spectroscopy. Next, we coated materials on substrates by different ways, using electrochemical workstation to test the photoelectric performance, as well as giving rational analysis for the results.In the preparation of MoS2, we research the factors influencing on the morphology of pure block by adjusting the hydrothermal temperature and reaction time. According to the XRD test results, we find the (002) crystal plane diffraction peak has the strongest intensity on the condition of 220? as well as 24 h. That is to say under the dual role of high temperature and high pressure, grain molecular layer is superposition and accumulation along the c axis, and achieve the highest crystallinity degree. SEM also give the same result.We prepared GO (graphite oxide) by modified Hummers method, and added it with different content into the reaction kettle together with sodium molybdate and thiourea to participate in the hydrothermal process to get the MoS2/RGO heterojunction samples. The SEM result indicate the mass fraction of GO directly determines the quality of MoS2 layers. When the content is 120 mg, the molybdenum sulfide in the heterojunction present less layers of nanometer structure, while in the other two samples, block structure can be found more or less. The main reason for which is that the GO content is too little to provide sufficient growth face for molybdenum sulfide, triggering edge curl and stacking of layers. Contrast pure bulk MoS2 and MoS2/RGO (120 mg) by Raman spectroscope and XRD spectrum, we find the molybdenum sulfide in the heterojunction material is less layer structure, which can be further observed from TEM result, showing less than 7 layers.Under scanning electron microscopy (SEM), we can find the membrane made by vacuum suction filter method present very smooth and uniform surface. Transferred onto the substrate and formed electrodes, its I-t and I-v response curves were measured. The result shows MoS2 has p-type semiconductor characteristics, and the MoS2/RGO heterojunction shows higher conductivity than pure block MoS2, which also displays larger photocurrent density (1.21 ?A/cm2), nearly 2 times higher than MoS2 (0.55?A/cm2). Finally the different suction filter volume content of electrode influencing on photocurrent response has also been discussed. The Results demonstrate that, within a certain range of the suction filter volume, the thicker the film, the larger photocurrent density it will behave. |
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