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Optical Engineering • Open Access

Model for thickness dependence of mobility and concentration in highly conductive zinc oxide
Author(s): David C. Look; Kevin D. Leedy; Arnold Kiefer; Bruce Claflin; Naho Itagaki; Koichi Matsushima; Iping Surhariadi

Paper Abstract

The dependences of the 294 and 10 K mobility μ and volume carrier concentration n on thickness (d=25 to 147 nm) are examined in aluminum-doped zinc oxide (AZO). Two AZO layers are grown at each thickness, one with and one without a 20-nm-thick ZnON buffer layer. Plots of the 10 K sheet concentration ns versus d for buffered (B) and unbuffered (UB) samples give straight lines of similar slope, n=8.36×1020 and 8.32×1020  cm−3, but different x-axis intercepts, δd=−4 and +13  nm, respectively. Plots of ns versus d at 294 K produce substantially the same results. Plots of μ versus d can be well fitted with the equation μ(d)=μ()/[1+d*/(dδd)], where d* is the thickness for which μ() is reduced by a factor 2. For the B and UB samples, d*=7 and 23 nm, respectively, showing the efficacy of the ZnON buffer. Finally, from n and μ() we can use degenerate electron scattering theory to calculate bulk donor and acceptor concentrations of 1.23×1021  cm−3 and 1.95×1020 cm−3, respectively, and Drude theory to predict a plasmonic resonance at 1.34 μm. The latter is confirmed by reflectance measurements

Paper Details

Date Published: 13 March 2013
PDF: 6 pages
Opt. Eng. 52(3) 033801 doi: 10.1117/1.OE.52.3.033801
Published in: Optical Engineering Volume 52, Issue 3
Show Author Affiliations
David C. Look, Wright State Univ. (United States)
Wyle Labs. (United States)
Air Force Research Lab. (United States)
Kevin D. Leedy, Air Force Research Lab. (United States)
Arnold Kiefer, Air Force Research Lab. (United States)
Bruce Claflin, Air Force Research Lab. (United States)
Naho Itagaki, Kyushu Univ. (Japan)
Koichi Matsushima, Kyushu Univ. (Japan)
Iping Surhariadi, Kyushu Univ. (Japan)

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