Research Of Planar On-Chip Micro-Supercapacitors Based On Graphene By Chemical Vapor Deposition

With the development of economy and technology,people are increasingly demanding electronic devices,and multi-functionalization and miniaturization have becomethedevelopmenttrendofenergystoragedevices.Planar micro-supercapacitors have strong energy storage capability,high instantaneous power,and can be integrated as power sources with micro/nano-scale electronic devices,thus becoming a research hotspot.Graphene has the advantages of thin structure,high conductivity,high specific surface area and high specific capacitance.Therefore,in the field of electrode materials of micro-supercapacitors,graphene has broad application prospects.In this paper,a graphene film is prepared by chemical vapor deposition,and then transferred to the surface of the silicon substrate by chemical reaction.By comparing the quality and electrical properties of graphene films prepared at different growth temperatures and different growth times,it can be seen that the prepared graphene film has good quality at a growth temperature of 1000?and a growth time of 30min,and the square resistance is 1.836k?/sq.In this paper,a graphene film is used as planar on-chip electrode,and planar on-chip micro-supercapacitors are prepared by photolithography and sputtering.The device area is constant,and the ratio of electrode width to electrode gap is 3:1.By comparing the cyclic voltammetry results of supercapacitors with different electrode widths?150?m,210?m,240?m?,it is found that as the electrode width became narrower,the distance between ions was shortened,and area capacitance,energy density and power density of planar on-chip micro-supercapacitors are increasing.Therefore,the performance of planar on-chip micro-supercapacitors with a narrower electrode width is better.The device with 150?m electrode width was tested.At a scan rate of 0.1Vs^-1,the area capacitance and energy density of the device with50?m electrode gap are 3.155?Fcm^-22 and 3.505mWhcm^-3,respectively.And its cyclic stability is up to 93.8%after 2500 cycles.Further,the planar on-chip micro-supercapacitors with the electrode width of the order of 10?m is explored.Then a planar on-chip micro-supercapacitor with electrode of 30?m and electrode gap of 10?m was prepared.At a scan rate of 0.01Vs^-1,the area capacitance,stack capacitance and energy density of the device with 10?m electrode gap were20.160?Fcm^-2,162.128Fcm^-33 and 2.400mWhcm^-3,respectively.At a scan rate of1Vs^-1,the device has a power density of 28.455Wcm^-3.The shortest time for discharge with an efficiency of more than 50%is 0.681ms.