Photocurrent Spectroscopy of single ZB, WZ InP Nanowire devices

ORAL

Abstract

Photocurrent spectroscopy was performed on single InP nanowire devices having either zinc-blende (ZB) or wurtzite (WZ) crystal structures at 300~K and 10~K. Photolithography was used to fabricate Ohmic Ti/Al metal contact pads separated by 5 $\mu $m. Using a monochromatic white light set up or a tunable (1.30 to 1.55 eV) CW laser, the photocurrent is measured as a function of bias voltage and excitation energy. At room temperature, the lowest energy band of In WZ (1.408~eV) is found to be 70 meV above the ZB band gap (1.338~eV), consistent with previous photoluminescence measurements. At low temperatures (10 K), the ZB device shows strong evidence for a broadened excitonic resonance peak at 1.432 eV and the WZ device shows three excitonic peaks at 1.504 eV, 1.56 eV, and 1.65 eV corresponding to the A,B and C valence band energies, respectively, which coincide with recent photoluminescence excitation measurements. Support for this work was provided by the NSF ({\#}0701703, {\#}0806700 and {\#}0806572) and the Australian Research Council.

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Authors

  • K. Pemasiri

    • University of Cincinnati, Cincinnati, OH

  • S. Perera

    • University of Cincinnati, Cincinnati, OH

  • A. Wade

    • University of Cincinnati, Cincinnati, OH

  • H.E. Jackson

    • University of Cincinnati, Cincinnati, OH

  • L.M. Smith

    • University of Cincinnati, Cincinnati, OH

  • J.M. Yarrison-Rice

    • Miami University, Oxford, OH

  • S. Paiman

    • Australian National University, Canberra, Australia

  • Q. Gao

    • Australian National University, Canberra, Australia

  • H.H. Tan

    • Australian National University, Canberra, Australia

  • C. Jagadish

    • Australian National University, Canberra, Australia