Design And Research Of Raman Sensor Chip Based On Graphene/Precious Metal

With the development of technology,the research in micro-field is deepening gradually,and the characterization of material morphology and quality in micro-field has higher requirements.However,the existing testing methods have a series of problems,such as high testing cost,complex testing methods and so on.Especially in the field of precision measurement,a high precision micro-stress sensor is urgently needed.Graphene,as a new type of two-dimensional material,has attracted much attention in the scientific and industrial circles due to its unique two-dimensional structure.In this paper,a Raman sensor chip based on graphene/noble metal is designed.The fabrication process is studied,and the possibility of its application in micro-stress detection is discussed.Finally,it is used for the quality detection of nano-scale objects.Firstly,the preparation technology of graphene Raman sensing substrate is discussed.Firstly,basic graphs were prepared by photolithography.And the SiO₂ and a certain depth of silicon were removed by dry etching.80 nm Ag layer and 40 nm Au layer were sputtered on the substrates to enhance Raman scattering.At the same time,the suspended graphene was obtained through secondary spin-coating and sectional temperature-controlled transfer.Finally,the graphene/precious gold was prepared.Simple Raman test was carried out on Raman sensor chip.The 2D peak map of Raman mapping proved the integrity of graphene coverage.At the same time,the intensity map of Raman mapping proved the suspension of graphene above the hole.Secondly,the performance of graphene Raman sensor chip are tested.In order to measure the sensitivity of graphene to stress changes,a 3⁷?m polystyrene microsphere was spin-coated on the substrate,and the 2D peaks obtained from suspended graphene with nanoparticle varies from 3?m to 7?m were given.It was found that the Raman 2D peak position of graphene changed to 69.8 cm^-1 for every 1% deformation of graphene.At the same time,Raman mapping was carried out on the 3?m nanospheres.The mapping diagram showed the position of the 3?m spheres intuitively,which proved that the graphene Raman sensor chip has remarkable detection ability and can accurately detect the stress position of graphene.At the same time,the mechanism analysis of graphene/noble metal Raman sensor chip was completed.Firstly,the pressure change of graphene s was calculated by Chen Shanlin's model.The stress change of graphene caused by non-size polystyrene microspheres was calculated.The maximum stress of polystyrene microspheres at 7?m was calculated,and the effect of polystyrene microspheres on graphene was also calculated,which is 0.0855%.Then the relationship between the peak displacement and strain of 2D is calculated by Gruniesen parameter.It is found that for every 1%deformation of graphene,the change of Raman peak position of graphene is -72.3 cm^-1,which is in good agreement with the theoretical value.Finally,silica microspheres with a diameter of 6 microns verified the accuracy of the fitting curve.Raman measurements were completed.It was found that the position of the microspheres in the coordinate system coincided with the curve of displacement and stress changes of graphene Raman 2D peak,which proved the effectiveness of the sensor chip.