| Graphene has received a lot of attention due to its excellent physical and chemical properties and has great potential especially in the fields of electronics,optoelectronic devices,transmission electron microscope carrier network,etc.As the chemical vapor deposition(CVD)growth technology becomes more and more mature,the graphene transfer technology,which is a bridge between growth and application,needs to be developed urgently.However,the problems of doping,stress,contamination,and low efficiency of large area transfer in practical use of graphene films have not been perfectly solved.For the bilayer graphene constructed by transfer,interfacial contamination has always been a problem,and the bubble formed by interfacial contamination can greatly affect the performance of bilayer graphene.Therefore,it is important to identify the source of contaminants between bilayer graphene interface and develop a scientific method to eliminate or suppress them.In this thesis,we first developed a dry lamination technique for graphene based on electrochemical bubbling and etching,and investigated the effects of interfacial water-oxygen doping and stress on the Raman properties of graphene films,and then constructed a clean bilayer graphene based on the transfer method of dry lamination,and designed and processed the corresponding transfer equipment independently to realize the transfer construction of largearea reversed bilayer graphene.This dissertation consists of the following four parts:(1)Developed dry lamination technology for graphene based on electrochemical bubble delamination method and etching methodThe dry lamination technique of graphene films was achieved by optimizing the conditions of electrochemical delamination separation to ensure the integrity of graphene after transfer.The method is applicable to graphene on different metal growth substrates,and achieves large-area damage-free and clean graphene transfer.(2)Investigated the effects of interfacial water-oxygen doping and different target substrates on Raman of graphene filmsThe doping of graphene and the stress of the target substrate with different flatness are analyzed based on the position of the characteristic peaks of Raman spectroscopy,and a judgment is made for the subsequent transfer method and the selection of the target substrate.(3)Development of an interfacial clean bilayer graphene transfer construction method based on dry laminationThe sources of graphene interfacial contamination were revealed through systematic studies,and large-area ultra-flat bilayer graphene was stacked by backside to avoid the introduction of contaminants between two layers graphene.(4)Designed and fabricated large area graphene layer-by-layer transfer equipmentA laminating equipment were designed integrating vacuum,heating,pressure sensing,and angle control.The equipment enabled the construction of large-area interfacial clean twisted bilayer graphene. |
