纳米结构铁电膜的制备和物性及微结构表征
收稿日期: 2009-12-25
修回日期: 2010-02-12
网络出版日期: 2010-08-25
基金资助
国家自然科学基金面上项目(10874065); 教育部回国留学人员科研启动基金
Fabrication, Physical Properties and Microstructural Characterization of Nanostructured Ferroelectric Films
Received date: 2009-12-25
Revised date: 2010-02-12
Online published: 2010-08-25
采用脉冲激光淀积法在硅基氧化铝纳米有序孔膜版介质上(膜版孔径平均尺寸25 nm, 内生长Pt纳米线作为底电极一部分)制备了纳米结构的BaTiO3铁电膜(膜厚25nm), 并对其铁电和介电性能以及微结构进行了表征. 结果表明, BaTiO3 铁电纳米膜的介电常数随着测量频率的增加(103~106 Hz)从196缓慢下降到190; 介电损耗在低频区域(103 ~105 Hz)从0.005缓慢增加到0.007, 而在高频率区域(>105 Hz)快速增加到0.013. 薄膜的剩余极化强度约为 5uC/cm2, 矫顽场强约为 680 kV/cm. 剖面(S)TEM像表明, BaTiO3铁电纳米膜与Pt纳米线(底电极)直接相连,它们之间的界面具有一定程度的弯曲. 为兼顾氧化铝纳米有序孔膜版内的金属纳米线有序分布及BaTiO3纳米膜的结晶度, 选择合适的退火温度是制备工艺中的关键因素.
朱信华, 宋 晔, 杭启明, 朱健民, 周顺华, 刘治国 . 纳米结构铁电膜的制备和物性及微结构表征[J]. 无机材料学报, 2010 , 25(9) : 966 -970 . DOI: 10.3724/SP.J.1077.2010.00966
By using pulsed laser deposition method, nanostructured BaTiO3 ferroelectric films (with a thickness of 25 nm) were grown on Si substrates and coated by nanoporous alumina membranes (NAMs) with an average pore size of 25 nm. Metal Pt nanowires were embedded in NAMs as a part of the bottom electrode. The dielectric and ferroelectric properties, and microstructure of the nanostructured BaTiO3 films were characterized. The results show that the dielectric constant of the BaTiO3 nanofilms is decreased slowly from 196 to 190 as the increase of measured frequency from 103 Hz to 106 Hz, and their dielectric loss is increased slowly from 0.005 to 0.007 in the low frequency range from 103 Hz to 105 Hz, whereas quickly increased up to 0.013 at high frequencies over 105 Hz. The remanent polarization and the coercive field of the BaTiO3 nanofilms are 5 uC/cm2 and 680 kV/cm, respectively. Cross-sectional (scanning) transmission electron microscope (TEM) images demonstrate that the BaTiO3 nanofilms contact directly with the Pt nanowires, and the interface between them has some degree of waviness. Suitable post-annealing temperature is the critical processing parameter of fabricating nanostructured ferroelectric films as considering a trade-off between the ordered degree of metal nanowires within NAMs and the crystallinity of ferroelectric nanofilms.
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