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Study Of Two-dimentional MoS2 And Pentacene/MoS2 Heterojunction

Posted on:2020-04-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z Y BaiFull Text:PDF
GTID:2381330623456595Subject:Physics
Abstract/Summary:PDF Full Text Request
As one kind of two-dimensional layered materials,molybdenum disulfide?MoS2?has excellent optical,electrical and mechanical properties.From the preparation methods to the application,or to the combining with other materials,MoS2 has received extensive attention for researchers.Basing on the chemical vapor deposition method and the combination of MoS2 with organic material pentacene,the controlled growth of MoS2,and the influence of single-layer MoS2 for the growth mechanism,light absorption and Raman properties of pentacene were studied;meanwhile,prepared the pentacene/MoS2 van der Waals heterojunction,and electron transport properties were discussed.The research will be contributed to the optoelectronic field.Specific work and research results are:1.MoS2 was prepared by chemical vapor deposition method,and the effects of growth temperature,argon flow rate,molybdenum trioxide?MoO3?powder quality,sulfur powder quality and growth time on the morphology and size of MoS2 were explored.The samples were characterized by optical microscopy,X-ray diffraction,Raman spectroscopy and atomic force microscopy.The experimental results showed:when the reaction temperature was 800?,the quality of molybdenum trioxide powder and sulfur powder were controlled to 5mg and 1.2g respectively,the argon flow rate was 50sccm,and the growth time was 10minutes,the single-layer MoS2would be obtained and its crystal morphology was triangle with 60?m in size and0.7nm in thickness.2.The effects of single-layer MoS2 on the properties of pentacene were investigated.The results showed:the flatness and compactness of the pentacene deposited on MoS2substrate was better than on SiO2/Si substrate when scanned by atomic force microscopy,indicating two-dimensional van der Waals surface is more conducive to the deposition of organic molecules,and will provide a basis for the further application of two-dimensional organic materials;MoS2 and pentacene had no influence on each other for the absorption spectrum;the MoS2 substrate enhanced the Raman scattering intensity of pentacene and had no effect on its peak position,this is because two-dimensional MoS2 can be used as an ideal surface-enhanced Raman scattering substrate and promotes interlayer electron transfer with organic small molecules without affecting their structure.3.Pentacene/MoS2 heterojunction was prepared and its electron transport mechanism was studied.The heterojunction obtained in this paper had ideal rectifier characteristic.By analyzing the ln?I/V2?-1/V curve,it was found that Fowler-Nordheim tunneling phenomenon exists in this heterojunction.log?I?-log?V?curve showed that,when the applied voltage was in the low voltage region of 0-1V,charge conduction was dominated by thermally excited carriers;when the applied voltage was higher than 1V,the charge conduction was controlled by the space charge limiting current mechanism.
Keywords/Search Tags:Two dimensional material, Chemical vapor deposition method, Heterojunction, Optical and electrical properties
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