中国物理B ›› 2004, Vol. 13 ›› Issue (4): 522-528.doi: 10.1088/1009-1963/13/4/019

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Nonlinear current－voltage characteristics of sintered tungsten－vanadium oxide

刘祖黎1, 杨林峰1, 王豫1, 王传聪1, 姚凯伦2   

  1. (1)Department of Physics and State Key Laboratory of Laser Technology, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; (2)Department of Physics and State Key Laboratory of Laser Technology, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; The International Center of Materials Physics, Chinese Academy of Sciences, Shenyang 110012, China
  • 收稿日期:2003-05-30 修回日期:2003-10-15 出版日期:2005-04-22 发布日期:2004-04-20

Nonlinear current－voltage characteristics of sintered tungsten－vanadium oxide

Liu Zu-Li (刘祖黎)a, Yang Lin-Feng (杨林峰)a, Wang Yu (王豫)a, Wang Chuan-Cong (王传聪)a, Yao Kai-Lun (姚凯伦)b   

  1. a Department of Physics and State Key Laboratory of Laser Technology, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; b Department of Physics and State Key Laboratory of Laser Technology, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; The International Center of Materials Physics, Chinese Academy of Sciences, Shenyang 110012, China
  • Received:2003-05-30 Revised:2003-10-15 Online:2005-04-22 Published:2004-04-20

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摘要： We have studied the densification behaviour, microstructure and electrical properties of WO_3 ceramics with V_2O_5 as the additive ranging from 0.5 to 15mol%. Scanning electron microscopic photos indicated that the grain size of WO_3－V_2O_5 specimens is smaller than that of pure WO_3. The addition of V_2O_5 to WO_3 showed a tendency to enhance the densification rate and to restrict the grain growth. Electrical properties of all specimens were measured for different electrodes at different temperatures. The formation of the grain boundary barrier layer was confirmed by the non-ohmic I－V behaviour. The nonlinear coefficient was obtained at the current density J=0.01, 0.1 and 1mA/cm^2 for a series of WO_3－V_2O_5 samples. The V0.5mol% specimen showed an abnormal phenomenon that the nonlinear characteristics appeared at 350℃ and disappeared at lower and higher temperatures. This implies that it could be applied as a high-temperature varistor. The double Schottky barrier model was adopted to explain the phenomena for the WO_3-V_2O_5 varistors.

Abstract: We have studied the densification behaviour, microstructure and electrical properties of WO_3 ceramics with V_2O_5 as the additive ranging from 0.5 to 15mol%. Scanning electron microscopic photos indicated that the grain size of WO_3－V_2O_5 specimens is smaller than that of pure WO_3. The addition of V_2O_5 to WO_3 showed a tendency to enhance the densification rate and to restrict the grain growth. Electrical properties of all specimens were measured for different electrodes at different temperatures. The formation of the grain boundary barrier layer was confirmed by the non-ohmic I－V behaviour. The nonlinear coefficient was obtained at the current density J=0.01, 0.1 and 1mA/cm^2 for a series of WO_3－V_2O_5 samples. The V0.5mol% specimen showed an abnormal phenomenon that the nonlinear characteristics appeared at 350℃ and disappeared at lower and higher temperatures. This implies that it could be applied as a high-temperature varistor. The double Schottky barrier model was adopted to explain the phenomena for the WO_3-V_2O_5 varistors.

Key words: V_2O_5-WO_3 ceramics, current－voltage characteristics, microstructure

中图分类号:  (Surface double layers, Schottky barriers, and work functions)

  • 73.30.+y
81.20.Ev (Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation) 73.40.Qv (Metal-insulator-semiconductor structures (including semiconductor-to-insulator))