| Title |
Annealing Effects of ZnO Seed Layers on Structural and Optical Properties of ZnO Nanorods Grown on R-plane Sapphire Substrates by Hydrothermal Method |
| Authors |
(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) |
| DOI |
https://doi.org/10.3365/KJMM.2015.53.2.139 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
hydrothermal synthesis; optical materials; nanostructured materials; annealing; optical properties; scanning electron microscopy |
| 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. |