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Optical Engineering • Open Access

Dopant profiles in heavily doped ZnO
Author(s): Bruce Claflin; Kevin D. Leedy; David C. Look

Paper Abstract

X-ray photoelectron spectroscopy (XPS) is used to compare the composition as a function of depth of as-grown zinc oxide (ZnO) films heavily doped with Ga and similar samples annealed in air for 10 min at 600°C, with particular attention given to the near-surface region. Films are grown by pulsed laser deposition (PLD) using a ZnO target containing 3 wt% Ga 2 O 3 . Electrical properties of these samples are determined from temperature-dependent Hall-effect measurements. The as-grown film has the following characteristics: (1) ∼11 Zn:O ratio with a Ga concentration of ∼3.3 at %; (2) no excess Ga in the near-surface region; and (3) excellent electrical characteristics: ρ=2.42×10 −4  Ω-cm , n=8.05×10 20   cm −3 , and μ=32.1   cm 2 /V-s -s at 300 K. For the annealed sample: (1) the Zn:O ratio remains ∼11 , but the Ga concentration is ∼3 at %, which is ∼10% lower than in the as-grown film; (2) ∼7 at % Ga is measured in the near-surface region; and (3) a significant increase in resistivity to ρ[/i]=0.99  Ω-cm , n=1.97×10 18   cm −3 , and μ=3.2  cm 2 /V-s at 300 K. Analysis of the O chemical shift suggests formation of a mixed ZnO/Ga 2 O 3 surface layer ≤5-nm -thick accounts for the observed changes in the Ga profile after annealing.

Paper Details

Date Published: 7 May 2013
PDF: 5 pages
Opt. Eng. 52(5) 053801 doi: 10.1117/1.OE.52.5.053801
Published in: Optical Engineering Volume 52, Issue 5
Show Author Affiliations
Bruce Claflin, Air Force Research Lab. (United States)
Kevin D. Leedy, Air Force Research Lab. (United States)
David C. Look, Air Force Research Lab. (United States)


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