Title :
The microstructure and conduction mechanism of the nonlinear ZnO varistor with Al2O3 additions
Author :
Han, Se-Won ; Kang, Hyung-Boo ; Ko, Kwang-Cheol ; Kim, Hyung-Sik
Author_Institution :
Han Yang Univ., Seoul, South Korea
Abstract :
The microstructure and electrical properties of nonlinear ZnO varistors with Al2O3 additions are investigated. The variation of nonlinear behavior with Al2O3 additions is indicated from J-E and C-V measurement to be a result of the change of the interface defects density Nt at the grain boundaries and the donor concentration Nd in the ZnO grains. The optimum composition which has a nonlinear coefficient α of ~57 was observed in the sample with 0.005 wt.% Al2O3 additions. The conduction mechanism in the pre-breakdown region is consistent with a Schottky thermal emission process obeying a relation given by J∝exp[-(φ-βE1/2)/kT] and the conduction process at the breakdown region follows Fowler-Nordheim tunneling
Keywords :
II-VI semiconductors; alumina; capacitance; ceramics; defect states; electric breakdown; grain boundaries; interface states; leakage currents; tunnelling; varistors; zinc compounds; Al2O3 additions; C-V measurement; Fowler-Nordheim tunneling; J-E measurement; Schottky thermal emission process; ZnO; ZnO-Al2O3; breakdown region; conduction mechanism; donor concentration; electrical properties; grain boundaries; interface defects density; microstructure; nonlinear ZnO varistors; nonlinear coefficient; optimum composition; pre-breakdown region; Capacitance-voltage characteristics; Current density; Density measurement; Dielectric measurements; Grain boundaries; Microstructure; Neodymium; Varistors; Voltage; Zinc oxide;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1997., Proceedings of the 5th International Conference on
Conference_Location :
Seoul
Print_ISBN :
0-7803-2651-2
DOI :
10.1109/ICPADM.1997.616574
