Research On The Electron Trap And Properties Of ZnO Semiconductor Material

ZnO varistors have been widely used in electronic and electrical power devices and systems because of excellent nonlinear V-I characteristics and high absorbance of electric current surges.With the SMT(Surface Mounted Technology) development, traditional ZnO varistors can not meet the multilayer thin films lamination structure nappe varistor ceramics and metal electrode low temperature co-fire need.However, the best character of ZnO-V2O5 varistor can sinter in common furnace during lower temperature (900℃),not only settling the problem relate to upon, but also saving energy sources.Firstly, the paper studied the dual effects of V2O5 in ZnO-V2O5 varistor ceramics during low temperature sintering. The binary varistor ceramic samples of V2O5 filled with ZnO at 2.5×10-3mol were prepared, the valence of V ion was studied by ESR(Electron Spin Resonance). The results show that V5+ whose valence changes is an acceptor impurity and after heat treatment especially at 655℃.The phenomenon is consistent with the result of the DTA(Differential Thermal Analysis). The result of DTA indicates that V2O5 has a phase transformation absorption peak at 655℃while the signal of ESR of low valence of V ion is the strongest. The results of V-I nonlinear testing indicated that the macroscopical nonlinear coefficient improves as long as the ESR signal of low valence V ion becomes strong. Meanwhile, V2O5 serves as a liquid phase additive, due to its low melting point making ZnO-V2O5 varistor ceramic densifing at 900℃. Continuously, the best component of ZnO-V2O5 varistor in low temperature sintering and multifunctional effects were studied. Varistors with excellent electrical properties have been produced in low temperature (900℃) sintering by changing the content of ZnO and V2O5 powders and using different heat treatment system. The nonlinear coefficient is more than 40 when the content of...