CaCu_3Ti_4O_(12)陶瓷深陷阱松弛特性研究

Investigation on Relaxation Properties of Deep Bulk Trap in CaCu_3Ti_4O_(12) ceramics

研究了固相反应法及共沉淀法制备的CaCu3Ti4O12陶瓷深陷阱松弛特性.测试了CaCu3Ti4O12陶瓷在频率为0.1～107Hz,温度为–100～100℃的范围内的介电频谱及温谱.通过对不同温度下介电频谱的分析,研究了双Schottky势垒结构中深陷阱松弛特性.研究表明:在交流小信号作用下,由于Schottky势垒中深陷阱与Fermi能级的上下关系发生变化,引起深陷阱电子发射和俘获即电子松弛过程,在介电频谱中表现为松弛峰;并且由介电谱的分析结果可得深陷阱能级等微观参数.比较不同试样的深陷阱参数可知:在CaCu3Ti4O12陶瓷中,在导带以下约0.52和0.12 eV的能级处存在由本征缺陷产生的深陷阱.介电温谱与频谱的分析类似,二者可以互为补充.

The relaxation properties of deep bulk trap in CaCu3Ti4O12 ceramics prepared by solid state reaction and coprecipitation method were investigated. Dielectric spectra at frequency from 0.1 Hz to 107 Hz and in the temperature range from -100℃ to 100℃ were measured. With the analysis of dielectric spectra at different temperature, deep bulk trap relaxation in double Schottky barrier was studied. The relative position between deep bulk trap and Fermi level changed in double Schottky barrier under small AC signal, resulted in electron emission and capture of deep bulk trap, namely relaxation, which exhibited as a peak in dielectric frequency spectra. Furthermore deep bulk trap level, can be received based on frequency spectra analysis. Compared with the parameters of different samples, it is found that there exist deep bulk traps caused by interior defect at the levels with 0.52 eV and 0.12 eV lower than conduction band. The analysis of dielectric temperature spectra is similar, which can be complement for dielectric frequence spectra analysis.