Study Of Graphene Material Gas Sensitive Performance And Field Effect Transistor Structure Design

Graphene oxide(GO)was prepared from graphite oxide which was prepared using modified Hummers method.And the GO film samples were prepared by spin coating method with the different concentration of GO aqueous dispersion;The different reduced graphene oxide samples were performed by annealing in the temperature range of100~350?;One-step methods were performed to prepared graphene-PANI composite materials(r GO-PANI);Structure and electrical properties of graphene FET(GFET)were designed and studied.Analyses for the structure,surface topography,and gas sensing behavior of the samples were carried out by XRD,FT-IR,Raman,AFM,SEM,TG-DTA and gas sensing experimental device.Especially,exploring the GO film thickness,thermal reduction degree and the composite quality ratio on the gas sensing properties,and the formation mechanism of graphene material was further uncovered.The results proves that,the forming process conditions of GO film has a great influence on the gas sensitive performance.Using spin coating process,along with the GO aqueous dispersion concentration increased from 1 to 5 mg/m L,the thickness of the film,in turn,to 18,35,65,102 and 139 nm.Results showed that the recovery time decreased from 37 to 8 s with the samples thickness decreased from 139 to 18 nm.As the relative humidity increased from 11.3~93.6%RH,the resistance of the samples were significantly reduced.The response time and recovery time of the humidity sensors were 2 and 8 s respectively,and the sensitivity approached 96.06%RH,suggesting the samples were of a good humidity sensing at the room temperature.The oxygen-containing functional group of graphene oxide were gradually reduced and its structure transformed to the graphite oxide structure,when graphene oxide was reduced from 100 to 350?.Thedisorder degree(ID/IG)increased from 0.85 to 1.59,then decreased to1.41,it shows a trend of increase on the whole.When the temperature was less than 150?,materials show features of graphite oxide,while materials show features of reduced graphite oxide,when the temperature was more than 250?.The materials treated at 150,200,and 350? exhibited n-type,ambipolar,and p-type behavior,respectively.Graphene oxide and its lower reduced products show a good sensitivity to H2.The gas sensor exhibited good sensitivity(88.56%),and response time(30s)to 100 ppm hydrogen gas at room temperature.r GO-PANI composite materials has better gas sensing than pure r GO and PANI.The sensitivity of r GO,PANI and r GO-PANI-1 is 13.92,41.49 and 50.26%,and response time is 422,296 and 156 s,and recovery time is 485,304 and 214 s exposed to 160 ppm ammonia gas.With the increase of PANI quality in composite material,the sensitivity showed a trend of decrease.When the mass ratio of r GO and PANI is1:1,1:2 and 1:3,sensitivity was 50.26,44.72 and 38.90% in turn.