He离子辐照对石墨烯微观结构及电学性能的影响  

Effect of He ion irradiation on microstructure and electrical properties of graphene

作　　者：张娜[1] 刘波[1] 林黎蔚[1] Zhang;Na Liu Bo;Lin Li-Wei(Key Laboratory of Radiation Physics and Technology of Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China)

机构地区：[1]四川大学原子核科学技术研究所教育部辐射物理及技术重点实验室

出　　处：《物理学报》2020年第1期311-316,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11605116)资助的课题~~

摘　　要：本文采用5.4 ke V不同剂量的He离子辐照单层石墨烯,利用X射线光电子能谱(XPS)、拉曼光谱(Raman)和半导体参数分析仪表征辐照前后石墨烯微观结构和电学性能变化.研究结果表明:随着辐照剂量增大,单层石墨烯的缺陷密度逐渐增加,当辐照剂量增至1.6×10^13 He+/cm^2,石墨烯开始由纳米晶结构向无定形碳结构转变,不断增多的缺陷致使石墨烯电导率持续降低,其电子输运机制也由玻尔兹曼扩散输运转变为跃迁输运;狄拉克电压(Vdirac)向正电压方向的偏移量随辐照剂量增大而增大,其主因是辐照缺陷和吸附杂质导致石墨烯P型掺杂效应增强.Graphene is a planar two-dimensional material composed of sp2-bonded carbon atoms with extraordinary electrical,optical and mechanical properties,and considered as one of the revolutionary electronic component materials in the future.Some studies have shown that the inert gas ion irradiation as a defect introducing technique can change the structure and properties of graphene without introducing additional effects.In this paper,the 5.4 keV He ion irradiation at the dose ranging from 0.7×10^13 cm-2 to 2.5×10^13 cm^-2 has a strong effect on graphene deposited by CVD technology.The X-ray photoelectron spectroscopy(XPS),Raman spectroscopy(Raman)and semi-conductor parameter analysis instrument are used to study the changes in the microstructure and electrical properties of graphene before and after irradiation.Detailed analysis shows that the defect density increases gradually with the irradiation dose increasing.Raman spectrum shows that when the irradiation dose increases to 1.6×1013 cm-2,the value of ID/IG begins to decrease,and XPS shows that the irradiation changes the structure of C chemical bond in graphene which causes the bonding state of C-C sp2 to be destroyed and partly converted into the C-C sp3 bonding state.Therefore,the structure of graphene begins to transform from nano-crystalline structure into sp3 amorphous structure.Simultaneously,increasing defects causes the graphene conductivity to continuously decrease,and also gives rise to the electrical transition from defect scattering mechanism based on Boltzmann transport to the hopping transport.The positive voltage direction offset of Vdirac increases nearly in direct proportion,which is due to the enhancement of graphene’s ptype doping effect caused by defects and adsorbed impurities.This work conduces to the understanding the mechanism of He ion interaction with graphene,and also provides an effective way of controlling the electronic properties.

关 键 词：石墨烯 He离子辐照 微观结构 电学性能 

分 类 号：TB3[一般工业技术—材料科学与工程]