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Vol.57, No.8, 506 ~ 510, 2019
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| Title |
| Effects of Rapid Thermal Annealing on the Structural, Optical, and Electrical Properties of ZnO/Ag/SnO2 Tri-Layer Films |
| Su-hyeon Choe , Yu-sung Kim , Jin-young Choi , Yun-je Park , Byung-chul Cha , Young-min Kong , Daeil Kim |
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| Abstract |
| ZnO 50 nm/Ag 10 nm/SnO2 50 nm (ZAS) tri-layer films were deposited on a glass substrate by RF and DC magnetron sputtering and then underwent rapid thermal annealing in a low vacuum of 1×10-3 Torr to investigate the effects of post-deposition annealing on the optical and electrical properties of the films. The peak intensity of the XRD pattern related to the ZnO (002) peak of the annealed films was higher than that of the as-deposited film and the full width at half-maximum of the ZnO (002) diffraction peak of the annealed films was smaller than that of the as-deposited film. Therefore, the crystallinity of ZnO was improved by rapid annealing. However, crystallization of the Ag interlayer and SnO2 surface layer were not significantly affected by the annealing temperature, compared with the ZnO bottom layer. From the observed electrical properties and optical band gap, it was concluded that the blue shift in the optical band gap is related to the carrier density of the films. The band gap increased from 4.19 eV to 4.24 eV, with the carrier density increasing from 7.09 × 1021 cm-3 to 7.77 × 1021 cm-3. However, the film annealed at 450 ℃ showed a decreased band gap energy of 4.17 eV due to the decreased carrier density of 6.80 × 1021 cm-3. The as-deposited ZAS films showed a sheet resistance of 11.0 Ω/□ and a visible transmittance of 80.8%, whereas the films annealed at 450 ℃ had a higher visible transmittance of 82.3% and a lower sheet resistance of 6.55 Ω/□. The results indicate that ZAS thin films may be possible substitutes for conventional Sn-doped In2O3 transparent electrodes in various optoelectronic devices.
(Received May 13, 2019; Accepted June 20, 2019) |
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| Key Words |
| ZnO/Ag/SnO2, magnetron sputtering, annealing, AFM, XRD |
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