title: Ultrafast Photodetection in the Quantum Wells of Single AlGaAs/GaAs-Based Nanowires.
abstract: We investigate the ultrafast optoelectronic properties of single Al0.3Ga0.7As/GaAs core-shell nanowires. The nanowires contain GaAs-based quantum wells. For a resonant excitation of the quantum wells, we find a picosecond photocurrent which is consistent with an ultrafast lateral expansion of the photogenerated charge carriers. This Dember-effect does not occur for an excitation of the GaAs-based core of the nanowires. Instead, the core exhibits an ultrafast displacement current and a photothermoelectric current at the metal Schottky contacts. Our results uncover the optoelectronic dynamics in semiconductor core-shell nanowires comprising quantum wells, and they demonstrate the possibility to use the low-dimensional quantum well states therein for ultrafast photoswitches and photodetectors.
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Erhard
authors.forename: S
authors.initials: S
authors.lastname: Zenger
authors.forename: S
authors.initials: S
authors.lastname: Morkötter
authors.forename: D
authors.initials: D
authors.lastname: Rudolph
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.|Institute of Physics, Universität Augsburg , Universitätsstr. 1, D-86135 Augsburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Weiss
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.|Institute of Physics, Universität Augsburg , Universitätsstr. 1, D-86135 Augsburg, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Krenner
authors.affiliation: Institute of Physics, Universität Augsburg , Universitätsstr. 1, D-86135 Augsburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Karl
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Abstreiter
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.
authors.forename: J J
authors.initials: JJ
authors.lastname: Finley
authors.forename: G
authors.initials: G
authors.lastname: Koblmüller
authors.affiliation: Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 München, Germany.
authors.forename: A W
authors.initials: AW
authors.lastname: Holleitner
keywords: GaAs/AlGaAs-core−shell nanowires; quantum well; ultrafast photodetector; ultrafast photoswitch