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Oxygen rich p-type ZnO thin films using wet chemical route with enhanced carrier concentration by temperature-dependent tuning of acceptor defects
Citation
Usman Ilyas, Rawat, R. S., Tan, T. L., Lee, P., Chen, R., Sun, H. D., Li, F., & Zhang, S. (2011). Oxygen rich p-type ZnO thin films using wet chemical route with enhanced carrier concentration by temperature-dependent tuning of acceptor defects. Journal of Applied Physics, 110(9), Article 093522. https://doi.org/10.1063/1.3660284
Author
Usman Ilyas
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Chen, R.
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Sun, H. D.
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Li, Fengji
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Zhang, Sam
Abstract
This paper reports the temperature-dependent tailoring of acceptor defects in oxygen rich ZnO thin films, for enhanced p-type conductivity. The oxygen rich p-type ZnO thin films were successfully grown by pulsed laser deposition on silicon substrate at different postdeposition annealing temperatures (500–800 °C). The oxygen rich ZnO powder was synthesized by wet chemical method using zinc acetate dihydrate [Zn(CH3COO)2·2H2O] and potassium hydroxide (KOH) as precursors. The powder was then compressed and sintered to make pellets for pulsed laser deposition system. The x-ray diffraction analysis exhibits an improved crystallinity in thin films annealed at elevated temperatures with a temperature-dependent variation in lattice constants. An analysis of Auger Zn L 3 M 4,5 M 4,5 peak reveals a consistent decrease in interstitial zinc (Zn i ) exhibiting its temperature-dependent reversion to zinc lattice sites. Room temperature photoluminescence of the p-type ZnO shows a dominant deep level emission peak at ∼3.12 eV related to oxygen interstitials (acceptors). The relative concentration of oxygen interstitials (O i ) increases with increase in annealing temperature, resulting in enhanced hole carrier concentration. The maximum hole carrier concentration of 6.8 × 1014 cm−3 (indicating p-type conductivity) was estimated using Hall probe measurements for the thin film sample annealed at 700 °C.
Date Issued
2011
Publisher
American Institute of Physics
Journal
Journal of Applied Physics
DOI
10.1063/1.3660284