Get access

Ultrafast Dynamics of Exciton Formation in Semiconductor Nanowires

Authors

  • Chaw Keong Yong,

    1. Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
    Search for more papers by this author
  • Hannah J. Joyce,

    1. Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
    Search for more papers by this author
  • James Lloyd-Hughes,

    1. Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
    Search for more papers by this author
  • Qiang Gao,

    1. Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia
    Search for more papers by this author
  • Hark Hoe Tan,

    1. Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia
    Search for more papers by this author
  • Chennupati Jagadish,

    1. Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200, Australia
    Search for more papers by this author
  • Michael B. Johnston,

    1. Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
    Search for more papers by this author
  • Laura M. Herz

    Corresponding author
    1. Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
    • Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK.
    Search for more papers by this author

Abstract

The dynamics of free electron–hole pairs and excitons in GaAs–AlGaAs–GaAs core–shell–skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K. Following nonresonant excitation, a bimolecular interconversion of the initially generated electron–hole plasma into an exciton population is observed. This conducting-to-insulating transition appears to occur gradually over electron–hole charge pair densities of 2–4 × 1016 cm−3. The smoothness of the Mott transition is attributed to the slow carrier-cooling during the bimolecular interconversion of free charge carriers into excitons and to the presence of chemical-potential fluctuations leading to inhomogeneous spectral characteristics. These results demonstrate that high-quality nanowires are model systems for investigating fundamental scientific effects in 1D heterostructures.

Ancillary