Electrical properties of lightly Ga-doped ZnO nanowires

S. Alagha, S. Heedt, D. Vakulov, F. Mohammadbeigi, E. Senthil Kumar, Th Schäpers, D. Isheim, S. P. Watkins, K. L. Kavanagh

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

We investigated the growth, crystal structure, elemental composition and electrical transport characteristics of ZnO nanowires, a promising candidate for optoelectronic applications in the UV-range. Nominally-undoped and Ga-doped ZnO nanowires were grown by metal-organic chemical vapor deposition. Photoluminescence measurements confirmed the incorporation of Ga via donor-bound exciton emission. With atom-probe tomography we estimated an upper limit of the Ga impurity concentration (1018 cm-3). We studied the electrical transport characteristics of these nanowires with a W-nanoprobe technique inside a scanning electron microscope and with lithographically-defined contacts allowing back-gated measurements. An increase in apparent resistivity by two orders of magnitude with decreasing radius was measured with both techniques with a much larger distribution width for the nanoprobe method. A drop in the effective carrier concentration and mobility was found with decreasing radius which can be attributed to carrier depletion and enhanced scattering due to surface states. Little evidence of a change in resistivity was observed with Ga doping, which indicates that the concentration of native or background dopants is higher than the Ga doping concentration.

Original languageEnglish (US)
Article number125010
JournalSemiconductor Science and Technology
Volume32
Issue number12
DOIs
StatePublished - Oct 31 2017

Keywords

  • Ga-doping, MOCVD
  • atom-probe tomography
  • electrical transport
  • nanowire, ZnO

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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