Effects of Ar vs. O2 ambient on pulsed-laser-deposited Ga-doped ZnO

Robin C. Scott, Kevin D. Leedy, Burhan Bayraktaroglu, David C. Look, Yong-Hang Zhang

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Ga-doped ZnO films were deposited by pulsed laser deposition (PLD) at 200 °C and 10 mTorr in either pure argon (Ar films) or in oxygen (O2 films). The bulk resistivity of the Ar films is <2×10-4 Ω cm at 300 K, two orders of magnitude lower than that of the O 2 films. In the Ar films, the donor concentration ND as determined by a detailed Hall-effect analysis is close to 100% of the total Ga concentration [Ga] measured by secondary ion mass spectrometry (SIMS), while in the O2 films ND is less than 50% of [Ga]. Furthermore, the compensation ratio K=NA/ND is >90% for the O 2 films and <60% for the Ar films. Yet, when the oxygen pressure is reduced to 0.2 mTorr, the O2 films have resistivities of about 5×10-4 Ω cm, approaching those of the Ar films. These results suggest that oxygen-rich environments produce Ga/O complexes that reduce the dopant activation efficiency and thus decrease ND and increase K. Some of these complexes may also contribute to the increase in deep centers observed in photoluminescence.

Original languageEnglish (US)
Pages (from-to)110-114
Number of pages5
JournalJournal of Crystal Growth
Volume324
Issue number1
DOIs
StatePublished - Jun 1 2011

Keywords

  • A3. Pulsed laser deposition
  • B1. Transparent conductive oxide

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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