Fabrication and Transport Studies of Graphene Nanostructures
Graphene is a semimetal with a zero bandgap, and therefore cannot be used for effective field-effect transistors (FETs) at room temperature. Theoretical study predicted an appreciable band gap opening with the formation of sub-10 nanometer graphene nanoribbons (GNRs). Here we demonstrate a rational approach to fabricate GNRs with sub-10 nm width by employing chemically synthesized nanowires (NWs) as the physical protection mask in oxygen plasma etching. GNR FETs with room temperature on-off ratio over 100 was demonstrated. We also fabricate graphene nanomesh (GNM) as a mimic of highly dense GNRs network using block copolymer nanolithography. GNM FETs can deliver large current nearly 100 times greater than individual GNR devices, whilst with a comparable on-off ratio that is tunable by varying the neck widths. The magnetotransport studies of these graphene nanostructures show significant enhancement in their conductance in a perpendicular magnetic field. A negative magnetoresistance of nearly 100％ was observed at low temperatures, with more than 50％ remaining at room temperature. The large values of the magnetoresistance we observe may be attributed to the reduction of quantum confinement by the formation of cyclotron orbits and the possible delocalization effect under the perpendicular magnetic field. These achievements can open up new avenues toward graphene based circuit application and provide new insights to the transport properties of graphene nanostructures.
Yu Huang Jingwei Bai
Department of Materials Science and Engineering,University of California, Los Angeles, California 90 Department of Materials Science and Engineering,University of California, Los Angeles, California 90
国际会议
上海
英文
1188-1191
2010-11-01（万方平台首次上网日期，不代表论文的发表时间）