Research On The Regulation Of Graphene Band Gap, Improvement Of Doping And Research On New Micro-nano Fiber Preparation Methods

Graphene is the name given to a two-dimensional crystal material with sp~2-hybridized carbon atoms packed into a honeycomb.Since discovered in 2004,graphene was considered the most promising material because of its excellent electrical,mechanical,optical and other properties.However,graphene has no energy gap itself,which greatly limit its application in the semiconductor field.And the doping is always introduced during processing.Therefore,how to open the gap of graphene and reduce the doping have become a hot topic in graphene research.Aiming at this problem,we use the quantum confinement effect to open the graphene bandgap at room temperature(sub-10 nm graphene structure is needed).We have used PMMA/Cr double masks to prepare sub-10 nm structure to open graphene bandgap based on the electron beam lithography(EBL).Then we compared the doping effect of Cr and PMMA mask on graphene.We also prepare graphene with structure of single row hole array to open its bandgap under the larger graphene size.The main contents are discussed as follow:(1)Process sub-10 nm graphene structure.Graphene was obtained by mechanical exfoliation.We use EBL,Iron beam etching(IBE)and Reactive iron beam etching(RIE)methods to process graphene.For optimized process condition,the quality of Cr particles,etching time of oxygen plasma and other parameters were investigated.Sub-10 nm graphene structure has been prepared.(2)The effect of Cr mask and PMMA mask on the performance of graphene was compared.PMMA and Cr were used as mask for processing graphene.It is proved that the Cr mask can reduce the doping of graphene compared to traditional PMMA photoresist by comparing the Raman spectra and the transfer curve of graphene processed by different masks.(3)The electrical properties of special graphene structures were studied.EBL and RIE technology were applied for graphene processing.The transfer cures under different temperatures of single row hole array structure graphene were investigated,then the size of band gap were calculate based on the transfer cures.Besides,we developed a facile method terms magneto-mechanical drawing to produce microfibers.This method is simple,safe and can produce ordered fibers,which have potential applications in mass production of fibers,flexible devices and drug delivery.