摘要
室温下在ＭＯＤ法制备的ＰＬＴ铁电薄膜的样品上，观察不同电场强度下电流随时间的变化，根据电流的变化情况，把电场划分为弱、中、强三个区间。在弱场下，电流随时间的变化可用幂指数的衰减来模拟，而且衰减系数随场强的增加有减小的趋势。在中强场时，电流随时间在水平方向上上下波动。在强场下，电流随时间在波动的同时不断增大。因此在对不同区间电流随时间变化Ｉ（ｔ）曲线分析的基础上，确定某一电场强度下的漏导电流，作出了Ｉ－Ｖ曲线。同时发现不同配方，在相同工艺条件下的样品，其弱、中、强场的数值区间是不一样的，因此作出的Ｉ－Ｖ曲线也有所区别。对非欧姆区的导电机理用空间电荷限制电流（ＳＣＬＣ）模型和晶界限制电流（ＧＢＬＣ）模型来解释，同时对样品正向与反向的导电机理进行了对比研究。
Lead lanthanum titanate(PLT)thin films were prepared by MOD process.Currenttime( I t ) curves at different voltages were measured at room temperature.Three different voltage ranges of low,intermediate and high field were divided according to current time( I t ) curves.In low field range,the change of current with time can be simulated by attenuation of power index,and the attenuation coefficient intends to decline with the increase of the applied electric field.Under the intermediate field,the I t curve started to horizontally fluctuate.Under the high field,the I t curve fluctuates and the current rised with time. I V cueves were obtained by analysing the I t cueves of different regions.Simultaneously we found that the zones of number of different electric fields werent the same when the samples had different formulas under the same process.Therefore the I V curves were different.The theory of non ohmic conduction can be explained by the models of space charge limited conduction(SCLC) and grain boundary limited conduction(GBLC).The theory of conduction was comparatively studied by the fields with different directions.Slow discharging process was observed after charging.The results are helpful in investigation of pyroelectric properties of the ferroelectric thin films.
出处
《压电与声光》
CAS
CSCD
北大核心
1997年第3期167-175,共9页
Piezoelectrics & Acoustooptics
基金
国家自然科学基金
关键词
铁电薄膜
漏导电流
PLT
ferroelectric film,leakage current, I V curves SCLC model,GBLC model
