Increased Photoconductivity Lifetime in GaAs Nanowires by Controlled n-Type and p-Type Doping

Jessica L. Boland, Alberto Casadei, Gozde Tuetuencueoglu, Federico Matteini, Christopher L. Davies, Fauzia Jabeen, Hannah J. Joyce, Laura M. Herz, Anna Fontcuberta i Morral, Michael B. Johnston

    Research output: Contribution to journalArticlepeer-review


    Controlled doping of GaAs nanowires is crucial for the development of nanowire-based electronic and optoelectronic devices. Here, we present a noncontact method based on time-resolved terahertz photoconductivity for assessing n- and p-type doping efficiency in nanowires. Using this technique, we measure extrinsic electron and hole concentrations in excess of 1018 cm–3 for GaAs nanowires with n-type and p-type doped shells. Furthermore, we show that controlled doping can significantly increase the photoconductivity lifetime of GaAs nanowires by over an order of magnitude: from 0.13 ns in undoped nanowires to 3.8 and 2.5 ns in n-doped and p-doped nanowires, respectively. Thus, controlled doping can be used to reduce the effects of parasitic surface recombination in optoelectronic nanowire devices, which is promising for nanowire devices, such as solar cells and nanowire lasers.
    Original languageEnglish
    Pages (from-to)4219-4227
    JournalACS Nano
    Issue number4
    Early online date9 Mar 2016
    Publication statusPublished - Apr 2016


    • GaAs
    • n-type doping
    • p-type doping
    • terahertz spectroscopy
    • photoconductivity
    • mobility
    • carrier lifetime
    • surface states
    • surface recombination
    • nanowires


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