Coherent control of electrical currents in semiconductor nanowires/‐tubes

Quantum interference control of electrical currents is well established in bulk semiconductors. It arises from the interference of one‐ and two‐photon absorption pathways. Here, the concept is transferred to one‐dimensional semiconductor nanostructures. First, currents are optically injected into aligned single‐walled carbon nanotube ensembles by phase‐related 700 and 1400 nm, 150 fs pulses. These transient currents are detected via the emitted THz radiation. In a second set of experiments, a phase‐stable superposition of ∼100 fs pulses from a compact erbium‐doped fiber source and their second harmonic is shown to induce ultrashort ∼µA current bursts in single unbiased GaAs nanowires. The current flow is characterized by charge accumulation and the related potential difference between the contacted ends of the ∼10 µm long wires. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)