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Preparation And Optical Properties Of Tungsten Sulfide Nanostructures

Posted on:2018-07-16Degree:MasterType:Thesis
Country:ChinaCandidate:J B ZhouFull Text:PDF
GTID:2321330533467382Subject:Physics, optic
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Monolayer WS2 has the advantages of ultrathin thickness,high carrier mobility,low resistivity and high switching ratio,exhibiting important application values in optoelectronic devices and valleytronics devices etc..Large area and high quality single layer film is an important prerequisite for developing WS2 based optoelectronic devices.In this thesis,the preparation and optical properties of high quality single layer WS2 thin films were studied.Detailed results are as follows:?1?A monolayer 2H-WS2 triangular film with high luminescence quality was obtained by chemical vapor deposition on a SiO2/Si substrate using a low melting point tungsten source.The full width at half maximum of the emission peak at 629.7 nm is about 18 nm?48 meV?.The WS2 films can present uniformly luminous or only edge emitting luminescence by adjusting the ratio of the reactant sources between tungsten and sulfur.?2?The effects of sapphire and SiO2/Si substrates on the Raman mode and luminescence position of monolayer WS2 were investigated.It was found that two kinds of substrates have same stress on monolayer WS2.However,blue shift occurred in the photoluminescence of the monolayer WS2 on sapphire substrate due to the doping of different charged impurities on the substrate surface.?3?WS2/Au composite was prepared by sputtering method.Comparative analysis of optical properties of monolayer WS2 and WS2/Au composite indicating that deposition of Au particles directly onto monolayer WS2 leads to luminescence quenching,but can enhance the inter layer A1g??? Raman vibration mode.
Keywords/Search Tags:Chemical vapor deposition, Monolayer WS2, Raman spectra, Photoluminescence
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