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Vol.53, No.2, 139 ~ 145, 2015
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| Title |
| Annealing Effects of ZnO Seed Layers on Structural and Optical Properties of ZnO Nanorods Grown on R-plane Sapphire Substrates by Hydrothermal Method |
| Min Su Kim , Gi Woong Nam , Dong Wan Kim , Ha Eun Kim , Haeri Kang , Wook Bin Lee , Hyon Kwang Choi , Yang Soo Kim , Jae Young Leem |
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| Abstract |
| ZnO nanorods were hydrothermally grown on R-plane sapphire substrates coated with an as-grown ZnO seed layer and with ZnO seed layers annealed at different temperatures. The effects of the seed-layer annealing temperature on the structural and optical properties of the ZnO nanorods were investigated using scanning electron microscopy, X-ray diffraction, and photoluminescence. ZnO nanorods and nanosheets grew on the as-prepared seed layer. Only ZnO nanorods grew on the ZnO seed layer annealed above 700 ℃. The structural and optical properties of the ZnO nanorods were significantly enhanced when the seed layers were annealed at 700 ℃. A cubic equation was used to establish the non-linear exciton radiative lifetime of the free exciton emission peak. Varshni’s empirical equation fitting parameters were α = 4 × 10.3 eV/K, β = 1 × 104 K, and Eg(0) = 3.335 eV; the activation energy was ~94.6 meV. |
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| Key Words |
| hydrothermal synthesis, optical materials, nanostructured materials, annealing, optical properties, scanning electron microscopy |
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