Investigation of Surface Potential of Ferroelectric Organic Molecules by Scanning Probe Microscopy
Investigation of Surface Potential of Ferroelectric Organic Molecules by Scanning Probe Microscopy
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通过扫描探针显微镜研究铁电有机分子的表面电势
DOI：
10.1143/jjap.38.3932
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发表时间：
1999
影响因子：
1.5
通讯作者：
ToshihisaHoriuchi Matsushige
中科院分区：
文献类型：
--
作者：
Xinqi Chen;Hirofumi Yamada;ToshihisaHoriuchi Matsushige
用扫描探针显微镜研究了偏氟乙烯和三氟乙烯共聚物铁电薄膜的表面电位。结果表明，在石墨衬底上沉积的共聚物膜显示负的表面电位。表面电位归因于衬底诱导效应，这导致在共聚物膜中的冻结偶极子。我们使用导电悬臂梁尖端在薄膜中制作了局部极化区域，并用改进的扫描力显微镜测量了薄膜的压电响应。所观察到的薄膜的压电响应的不对称行为可以一致地解释由冻结的铁电层的薄膜。局部极化区域的表面电位和压电响应图像也得到了。结果表明，从尖端转移的电荷过度补偿的定向偶极子和极化区域的表面电位归因于多余的电荷。
The surface potential of ferroelectric copolymer films of vinylidene fluoride and trifluoroethylene was investigated by scanning probe microscopy. The results reveal that the as-deposited copolymer films on a graphite substrate show a negative surface potential. The surface potential is ascribed to the substrate-induced effect, which causes frozen dipoles in the copolymer films. We made locally poled areas in the films using a conductive cantilever tip and measured the piezoelectric response of the films with a modified scanning force microscope. The observed asymmetric behavior of the piezoelectric response of the thin films can be consistently explained by the frozen ferroelectric layer in the films. Both surface potential and piezoresponse images of locally polarized areas were also obtained. The results indicate that the charge transferred from the tip overcompensated for the oriented dipoles and that the surface potential of the poled regions was attributed to the excess charge.