Quantum Transport in Semiconductor Nanowires

Semiconductor nanowires fabricated by means of a so-called bottom-up approach are very promising candidates as building blocks for future nanoelectronic device applications. In addition, semiconductor nanowires are also very interesting objects to study fundamental quantum phenomena, i.e. electron interference or spin transport. In order to address these questions, we investigated the transport properties of InN and InAs nanowires. By analyzing universal conductance fluctuations information on the phase coherence length is obtained. We could confirm that phase coherence can be maintained over several hundreds of nanometers. By employing GaAs/InAs core/shell nanowires regular magnetic flux periodic conductance oscillations are observed, when a magnetic field is applied along the nanowire axis. These oscillations originate from the presence of circular angular momentum states within the shell of the nanowire. In addition to normal metal contacts we also investigated structures with ferromagnetic Co electrodes. Here, we could demonstrate that spin injection from the ferromagnet into the nanowire is achieved.