The Preparation And Optical Properties Research Of CdS/MoS₂ Micro-nano Structure

Molybdenum disulfide crystal belongs to the hexagonal system and it is the indirect band gap semiconductor whose band gas is 1.29eV.Single-layer molybdenum disulfide has the graphene structure,and becomes the direct band semiconductors of 1.90 eV band-gap.Graphene-like molybdenum disulfide would have great application prospect as for its two-dimensional laminar layer structure and special band structure.In order to further understand the physical properties of the composite structure which is produced by the monolayer molybdenum disulfide and other one-dimensional nanostructures,this article mainly studies around the preparation and the photoluminescence properties of Molybdenum disulfide-Cadmium sulphide Micro-nano composite structure.We use the chemical vapor deposition method to synthesis single-layer molybdenum disulfide and the micro-nano composite structure with cadmium sulfide.Then the micro-nano composite structure is observed about the morphology and structure in the confocal microscopy system.And we found many different factors have impact on the growth in the CVD.It was found that using generated molybdenum disulfide produced by the molybdenum oxide and sulfur powder reaction in the experiment is more conducive to doping molybdenum disulfide in cadmium sulfide than directly using the molybdenum disulfide powder.The gas that contains a small amount of hydrogen is in favor of the production of the pure cadmium sulfide nano stucture,but not suitable for doping.Adding in very small amounts of tin dioxide can greatly induce the growth of the micro-nano composite structure.Keeping high temperature for 50 minutes or so would get the samples with suitable micro-nano size,which is good for the spectral characterization.Then we research the exciton recombination luminescence and relaxation effect by the micro zone spectrum method in the micro-nano structure.Trying to deeply understand the optical properties and the electronic structure of molybdenum disulfide,it would create smooth way for the next photoelectric device application.In view of the CdS/MoS₂luminescence spectrum experiment,we found that under 405 nm laser excitation the light wavelength of Cadmium sulphide?nanowires,nanosheet,nanobelt?splits into two peaks,the physical mechanism needs to be confirmed by the next experiment.There are a lot of weak emission peaks in 580 nm to 750 nm section when the CdS/MoS₂ micro-nano structure is excited by the 532 nm laser.We also find two characteristic peaks at 344 and366 wave number in the Raman spectra of the samples besides pure cadmium sulphide characteristic peaks,which may be caused by the doping of MoS₂.We test the doping cadmium sulfide nanowires or nanobelts using the SnO₂ and MoO₃ together as the raw material.There is a strong photoluminescence peak at 880 nm,and we suspect that it`s likely to come from Sn-Mo doping system.