Vol.53, No.10, 745 ~ 751, 2015
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Title |
Effects of Post- Heat Treatment of Nanocrystalline ZnO Thin Films deposited on Zn-Deposited FTO Substrates |
Ik Hyun Kim , Young Gyu Kim , Gi Woong Nam , Jae Young Leem |
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Abstract |
The effects of heat-treatment temperature on the structural and optical properties of ZnO thin films were investigated with field-effect scanning electron microscopy (SEM), X-ray diffraction analysis, and photoluminescence (PL) measurements. The ZnO thin films were grown on Zn-deposited fluorine-doped tin oxide substrates by sol-gel spin coating. The SEM images of the samples showed that their surfaces had a mountain-chain-like structure. The film annealed at 400 ℃ had the highest degree of alignment along the c-axis, and its residual stress was close to zero. The PL spectra of the ZnO thin films consisted of sharp near-band-edge emissions (NBE) and broad deep-level emissions (DLE) in the visible range. The DLE peaks exhibited a green-to-red shift with an increase in the temperature. The highest INBE/IDLE ratio was observed in the film annealed at 400 ℃. Thus, the optimal temperature for growing high-quality ZnO thin films on Zn-deposited FTO substrates is 400 ℃ |
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Key Words |
zinc oxide, FTO substrate, Zn buffer layer, spin coating, photoluminescence, post-heat treatment |
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