Physical meaning of conductivity spectra for ZnO ceramics
Physical meaning of conductivity spectra for ZnO ceramics
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DOI：
10.1088/1674-1056/21/9/097201
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发表时间：
2012-09
影响因子：
1.7
通讯作者：
Chen Peng-fei;Li Shengtao;Li Jianying;Ding Can;Yang Yan
中科院分区：
文献类型：
--
作者：
Chen Peng-fei;Li Shengtao;Li Jianying;Ding Can;Yang Yan
借助宽温度和频率范围内的宽带介电谱，测量了ZnO多晶陶瓷的电导率谱，并沿频率轴依次观察到类直流（DC）电导率和弛豫极化电导率。根据经典的德拜理论和科尔-科尔方程，讨论了两种电导率的物理意义。研究发现类直流电导率对应于晶界处肖特基势垒上的电子传输。弛豫极化电导率对应于本征点缺陷（锌间隙和氧空位）的电子陷阱弛豫。在高频区，弛豫电导率遵循普遍规律，以指数n等于Cole-Cole方程中的指数α作为无序程度的指标。
With the help of broadband dielectric spectroscopy in a wide temperature and frequency range, the conductivity spectra of ZnO polycrystalline ceramics are measured and the direct-current-like (DC-like) conductivity and relaxation polarization conductivity are observed successively along the frequency axis. According to the classical Debye theory and Cole—Cole equation, the physical meanings of the two conductivities are discussed. It is found that the DC-like conductivity corresponds to electron transportation over the Schottky barrier at the grainboundary. The relaxation polarization conductivity corresponds to electronic trap relaxation of intrinsic point defects (zinc interstitial and oxygen vacancy). When in the high frequency region, the relaxation conductivity obeys the universal law with the index n equal to the index α in the Cole—Cole equation as an indictor of disorder degree.