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We study experimentally electron transport in 1 dimensional wires and in particular semiconductor nanowires and carbon nanotubes. The wires and tubes are connected to source-drain contacts with gate electrodes in the substrate or on the surface. In the regime of weak coupling to the contacts we observe standard Coulomb blockade effects. We present level spectroscopy including a determination of the spin states. At proper values of magnetic field and electron number we tune into new Kondo regimes and observe an orbital Kondo effect and orbital+spin, or SU(4)-Kondo effect.
In the regime of strong coupling to the contacts interference effects are observed. In this regime and using superconducting contacts, we find supercurrents flowing through InAs-nanowires over micrometer length scales. The critical current is tunable by gate voltage making these devices a realization of the so-called JOFETs (Josephson FETs).
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