Sol−gel synthesis of Y2O3-doped ZnO thin films varistors and their electrical properties
(1. School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors,
Chinese Academy of Sciences, Beijing 100083, China;
3. State Key Laboratory of Electrical Insulation and Power Equipment,
Xi’an Jiaotong University, Xi’an 710049, China;
4. State Key Laboratory of Electronic Thin Films and Integrated Devices,
University of Electronic Science and Technology of China, Chengdu 610054, China;
5. Changzhou Engineering Research Institute of Jiangsu University, Changzhou 213000, China;
6. Changzhou Ming Errui Ceramics Co., Ltd., Changzhou 213102, China)
2. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors,
Chinese Academy of Sciences, Beijing 100083, China;
3. State Key Laboratory of Electrical Insulation and Power Equipment,
Xi’an Jiaotong University, Xi’an 710049, China;
4. State Key Laboratory of Electronic Thin Films and Integrated Devices,
University of Electronic Science and Technology of China, Chengdu 610054, China;
5. Changzhou Engineering Research Institute of Jiangsu University, Changzhou 213000, China;
6. Changzhou Ming Errui Ceramics Co., Ltd., Changzhou 213102, China)
Abstract: Y2O3-doped ZnO−Bi2O3 thin films were fabricated on silicon substrates by sol-gel process and annealed in air at 750 °C for 1 h. Microstructure and electrical properties of ZnO thin films were investigated. XRD analysis shows that all peaks of ZnO thin films are well matched with hexagonal wurtzite structure of ZnO. SEM results present that the ZnO grain size decreases with the increase of dopant concentration, which means that rare earth doped can refine the grain size. The thickness of each layer is uniform and the value of thickness is about 80 nm. The nonlinear V-I characteristics with the leakage current of 0.46 μA, the threshold field of 110 V/mm and the nonlinear coefficient of 3.1 could be achieved when the films contain 0.2% (mole fraction) yttrium ion.
Key words: zinc oxide; Y2O3 varistor; film; sol-gel process; electrical properties; microstructure