Electron transport in very clean, as-grown suspended carbon nanotubes.
Single-walled carbon nanotubes have shown a wealth of quantum transport phenomena thus far. Defect-free, unperturbed single-walled carbon nanotubes with well behaved or tunable metal contacts are important for probing the intrinsic electrical properties of nanotubes. Meeting these conditions experimentally is non-trivial owing to numerous disorder and randomizing factors. Here we show that approximately 1-microm-long fully suspended single-walled carbon nanotubes grown in place between metal contacts afford devices with well defined characteristics over much wider energy ranges than nanotubes pinned on substrates. Various low-temperature transport regimes in true-metallic, small- and large-bandgap semiconducting nanotubes are observed, including quantum states shell-filling, -splitting and -crossing in magnetic fields owing to the Aharonov-Bohm effect. The clean transport data show a correlation between the contact junction resistance and the various transport regimes in single-walled-carbon-nanotube devices. Furthermore, we show that electrical transport data can be used to probe the band structures of nanotubes, including nonlinear band dispersion.
Cao
Jien
J
Department of Chemistry and Laboratory for Advanced Materials, Stanford University, California 94305, USA.
Wang
Qian
Q
Dai
Hongjie
H
D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004574:Electromagnetic Fields; D004579:Electron Transport; D008422:Materials Testing; D037742:Nanotubes, Carbon / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D012666:Semiconductors
D037742:Nanotubes, Carbon