The Native Material Limit of Electron and Hole Mobilities in Semiconductor Nanowires

Jörg B. Kinzel, Florian J.R. Schülein, Matthias Weiß, Lisa Janker, Dominik D. Bühler, Michael Heigl, Daniel Rudolph, Stefanie Morkötter, Markus Döblinger, Max Bichler, Gerhard Abstreiter, Jonathan J. Finley, Achim Wixforth, Gregor Koblmüller, Hubert J. Krenner

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Piezoelectric surface acoustic waves are employed to induce radio frequency spatiotemporal dynamics of photogenerated electrons and holes in the GaAs core of individual GaAs/AlGaAs core/shell semiconductor nanowires. Comparison of the time-dependent interband optical recombination to numerical simulations allow to determine the charge carrier transport mobilities of electrons, μe = 500-250+500 cm2/(V s), holes, μh = 50-30+50 cm2/(V s) and their ratio μeh = (20 ± 5):1. Our method probes carrier transport at low carrier density. Thus, the obtained values represent the native material limit of these nanowires, determined by their structural properties. We show that for near-pristine nanowires, individual twin defects do not significantly affect electrical transport, in strong contrast to polytypic nanowires. In the acoustoelectrically modulated emission, we observe unambiguous signatures of (i) hole localization within long wurtzite-rich segments and (ii) electrons in zinc blende regions being reflected at the interface to a wurtzite-rich region. The experimentally observed periodic emission bursts are faithfully reproduced by advanced numerical simulations which include static band edge discontinuities between a single wurtzite segment in an otherwise pure zinc blende nanowire. Otherwise using the same input parameters as for near-pristine zinc blende nanowires, we can deduce from our simulations a minimum conduction band offset of ΔEC ≈ 20 meV at the interface between the zinc blende part and the wurtzite-rich region. These results furthermore confirm that a single wurtzite segment with sufficiently large band offsets efficiently traps holes and blocks electron transport.

Original languageEnglish
Pages (from-to)4942-4953
Number of pages12
JournalACS Nano
Volume10
Issue number5
DOIs
StatePublished - 24 May 2016

Keywords

  • acoustic charge transport
  • charge carrier mobility
  • nanowires
  • polytypism
  • surface acoustic waves

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