聚(偏氟乙烯-三氟乙烯)纳米薄膜极化反转与疲劳特性  

Study of ferroelectric switching and fatigue behaviors in poly(vinylidene fluoride-trifluoroethylene) copolymer nano-films

作　　者：杜晓莉[1,2] 张修丽[1,2,3] 刘宏波[2] 季鑫[1,3] 

机构地区：[1]上海工程技术大学基础教学学院,上海201620 [2]上海工程技术大学材料工程学院,上海201620 [3]上海工程技术大学光电子材料与器件研究所,上海201620

出　　处：《物理学报》2015年第16期397-405,共9页Acta Physica Sinica

基　　金：上海市自然科学基金(批准号:13ZR1418200);上海市教育委员会科研创新项目(批准号:15ZZ093)资助的课题~~

摘　　要：采用旋涂法制备了厚度为140 nm的聚(偏氟乙烯-三氟乙烯)[P(VDF-TrFE)]纳米薄膜,研究了不同退火温度以及环境相对湿度对薄膜的极化反转和疲劳性能的影响.运用X射线衍射仪、扫描电子显微镜和傅里叶变换红外光谱仪等测试技术对薄膜的微结构进行了表征.实验结果表明,通过不同温度的退火处理,P(VDF-TrFE)铁电薄膜的结晶度随着退火温度的升高而不断提高,并且一定的温度范围内的退火处理可以提高薄膜的极化性能;此外,P(VDF-TrFE)铁电薄膜性能还表现出一定的环境湿度的敏感特性,这与薄膜的物理性能和结构特点密切相关;P(VDF-TrFE)铁电薄膜在不同的环境湿度条件下表现出较好的电学特性,其漏电流均保持在107A/cm2的较低水平.本工作揭示了再退火过程对薄膜的极化反转速度和疲劳恢复特性的影响,并结合薄膜二次疲劳结果,探讨了薄膜可逆的内部疲劳恢复特性机理.The nano-films of poly （vinylidene fluoride-trifluoroethylene） （P（VDF-TrFE）） copolYmer, with mole ratio of VDF- TrFE 70/30, are deposited on titanium-metallized silicon wafer by spin coating technique. Annealing temperature and humidity dependence of polarization switching and fatigue babivors in ferroelectric P（VDF-TrFE） copolymer thin film capacitors have been investigated. Firstly, the effect of different annealing temperature on polarization behavior is revealed. It is found that the polarization of the film is improved by increasing annealing temperatures. When the annealing temperature is higher than 100 ~C, with increasing switching cycles, the ferroelectric polarization characteristics exhibit a trend of increasing firstly and then decreasing, a top value appears at the number of cycles near 104. A more appropriate heat treatment temperature is 130 ~C. Further analyses on the crystalline structures with X-ray diffraction show that the degree of crystallinity of the films is strongly dependent on the annealing temperature. It can be seen that the diffraction peak of the ferroelectric phase （6 phase） becomes very strong and sharp with increasing annealing temperatre. It is demonstrated that the effect of annealing temperature on ferroelectric properties could be explained by the changes of the degree of crystallinity in these films from the results of X-ray and the polarization behaviors. Meanwhile, the microstructure of the 140 nm film annealed at 130 ~C is obtained by using scanning electron microscope, which shows that the film exhibits a worm-like, dense, well-crystallized microstructure. Secondly, for the capacitor P（VDF-TrFE） films with a thickness of 140 nm, the ferroelectric polarization hysteresis loops as functions of electric field for the films at different relative humidities are achieved. It is obvious that the polarization properties depend on the relative humidity during the film preparation process, the polarizaiton fatigue can be further enhanced through a higher re

关 键 词：聚(偏氟乙烯-三氟乙烯)纳米薄膜 退火 湿度 疲劳 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O484[理学—固体物理]