Characterization of N-doped ZnO layers grown on (0 0 0 1) GaN/Al2O3 substrates by molecular beam epitaxy

D. C. Oh, A. Setiawan, J. J. Kim, H. J. Ko, H. Makino, Takashi Hanada, M. W. Cho, T. Yao

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12 Citations (Scopus)

Abstract

We investigated the optical properties and electrical properties of N-doped ZnO layers grown on (0 0 0 1) GaN/Al2O3 substrates by molecular beam epitaxy, employing 10 K photoluminescence (PL) measurements, current-voltage (IV) measurements, capacitance-voltage (CV) measurements, and 100 K photocapacitance (PHCAP) measurements. 10 K PL spectra showed that excitonic emission is dominant in N-doped ZnO layers grown after O-plasma exposure, while overall PL emission intensity is significantly reduced and deep level emission at around 2.0 ∼ 2.2 eV is dominant in N-doped ZnO layers grown after Zn exposure. IV and CV measurements showed that N-doped ZnO layers grown after Zn exposure have better Schottky diode characteristics than O-plasma exposed samples, and an N-doped ZnO layer grown at 300 °C after Zn exposure has best Schottky diode characteristics. This phenomenon is presumably due to lowered background electron concentration induced by the incorporation of N. PHCAP measurements for the N-doped ZnO layer revealed several midgap trap centers at 1.2 ∼1.8 eV below conduction band minimum.

Original languageEnglish
Pages (from-to)625-629
Number of pages5
JournalCurrent Applied Physics
Volume4
Issue number6
DOIs
Publication statusPublished - 2004 Nov 1

Keywords

  • Deep level
  • Schottky contact
  • ZnO

ASJC Scopus subject areas

  • Materials Science(all)
  • Physics and Astronomy(all)

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