Band Structure and Carrier Thermalization in InGaAs and InGaAs/InP Nanowires Probed by Transient Rayleigh Scattering and Photoluminescence

ORAL

Abstract

We use transient Rayleigh scattering (TRS) and photoluminescence (PL) to characterize the band structure and carrier thermalization of Wurtzite InGaAs and InGaAs-InP core-shell nanowires (NW). TRS measurements use an ultrafast (~150 fs) near-infrared pump (1.51 eV) and probe (0.79 - 1.16 eV) pulses. TRS spectra of a single NW exhibit a band-to-band transition substantially blue-shifted relative to the equivalent Zincblende band edge. PL measurements (with 1.51 eV excitation) of NW clusters confirm this transition as the fundamental Wurtzite band edge. Polarization analysis of the PL and TRS spectra indicate a smaller A-B splitting than observed in WZ GaAs. PL emission is enhanced dramatically in core-shell wires compared to core-only wires. Likewise, TRS measurements show longer carrier lifetime for core-shell wires, due to passivation by the InP shell. Thermalization modeling based on these measurements suggests that the core-only wires cool rapidly via optical phonon emission, whereas the core-shell wires cool by a slower process with early optical and later acoustic phonon emission.

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Presenters

  • Samuel M Linser

    Department of Physics, University of Cincinnati

Authors

  • Samuel M Linser

    Department of Physics, University of Cincinnati

  • Iraj Abbasian Shojaei

    Department of Physics, University of Cincinnati

  • Giriraj Jnawali

    Department of Physics, University of Cincinnati

  • Howard E Jackson

    Department of Physics, University of Cincinnati

  • Leigh Smith

    Department of Physics, University of Cincinnati, Physics, University of Cincinnati

  • Amira Ameruddin

    Department of Electronic and Materials Engineering, Australian National University

  • Philippe Caroff

    Department of Electronic and Materials Engineering, Australian National University

  • Hoe Tan

    Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra ACT, 0200, Australia, Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200, Australia, Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Department of Electronic and Materials Engineering, Australian National University

  • Chennupati Jagadish

    Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra ACT, 0200, Australia, Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200, Australia, Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University, Department of Electronic and Materials Engineering, Australian National University