Effects of Oxygen Annealing on Kaolin-Doped Zinc Oxide Discs

• Published in: Journal of physics. Conference series 2018-08, Vol.1083 (1), p.12006
• Main Authors: Azhari, F, Mahmud, S, Mohd Bakhori, S K, Che Pa, M F, Mohd Latiff, N S, Omar, A F
• Format: Article
• Language: English
• Subjects: Aluminum; Annealing; Ball milling; Crystallites; Electrical conduction; Electrical measurement; Electrical properties; Kaolin; Optical properties; Oxygen; Physics; Potential barriers; Raman spectra; Sintering (powder metallurgy); Zinc oxide; Zinc oxides
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1083/1/012006

ZnO nanostructures were used to prepare sintered ZnO dics that were pure ZnO discs (ZnO-100) and kaolin-doped ZnO discs (ZnO-97) containing 3 weight % of kaolin. The ZnO powder was mixed via ball milling process, pressed into discs and sintered at 1000 °C followed by annealing at 700 °C under oxygen ambient. The annealed discs were labeled as ZnO-100/O2 and ZnO-97/O2. Optical, structural and electrical properties were characterized using Raman scattering, XRD and current-voltage measurement. The crystallite size of ZnO was calculated using XRD data in that pure ZnO-100 had crystallite size of 33.034 nm and ZnO-100/O2 oxygen annealed had 41.972 nm. The XRD data also showed oxygen annealed kaolin-doped ZnO-97/O2 had a smaller crystallite size of 13.054 nm while unannealed kaolin-doped ZnO-97 had 14.285 nm. Kaolin doping and oxygen annealing on ZnO discs appeared to affect crystallite size. The resistance measured on the ZnO disc surface revealed that doped ZnO-97 had lower resistance (2 MΩ) compared to ZnO-100 (6 MΩ). On the other hand, annealed ZnO-97 O2 had a lower resistance (0.8 MΩ) compared to annealed ZnO-100 O2 (30 MΩ). The aluminum element in kaolin could have served as a dopant that lowered the potential barrier for electrical conduction to take place.