Study of rewritable thin-film memories using ferroelectric polymers

使用铁电聚合物可重写薄膜存储器的研究

基本信息

批准号：
12650875
负责人：
IKEDA Susumu
金额：
$ 2.11万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650875/
关键词：
ferroelectric polymer thin film memory VDF TrFE copolymer polymer dispersed liquid crystal nematic liquid crystal 5CB polarization internal field optical transmittance 高分子分散型液晶有機薄膜メモリー読み取り動作初期化

项目摘要

1. Ultra thin films of ferroelectric VDF/TrFE(vinylidene fluoride/ trifluoroethylene) copolymers were produced by use of spin-coating technique. We took aim at forming of submicron films whose polarization can be controlled by voltages less than about 10 V. The best condition for solvent, solution density and rate of rotation of spin coater was chosen by many tests. As the result, a thin film of 220 nm in thickness which exhibits a ferroelectric D-E hysteresis was obtained. This film can be used as a memory in an integral circuit. However, films of higher quality including higher ordered crystals are required to make a real memory, because the polarization reversal switching process observed in the submicron films described above is not so clear in comparison with those observed in films with the thickness more than 1μm.2. Memories have three elementary actions of writing, reading and initializing. About reading, we studied whether the change in the optical transmittance of the sample films can be used for the switching process of memories or not, in order to use them as the memory for optical circuit. We took up PDLC (polymer dispersed liquid crystal) composed of VDF/TrFE copolymer and nematic liquid crystal 5CB as a sample. The polarization of P(VDF/TrFE) was oriented by applying an external electric field to PDLC. The internal electric field originating from the ferroelectric polarization affected molecular orientation of the liquid crystal 5CB and changed the optical transmittance of PDLC. This result suggests that the changes in the optical transmittance can be used for the reading mechanism of the PDLC memory.From these results we conclude that the organic thin-film memory can be obtained using the ferroelectric properties of polymers.

1。铁电VDF/ TRFE（乙烯基氟/三氟乙烯）共聚物的超薄膜是通过使用自旋涂层技术产生的。我们采取的目的是形成偏振层的亚微米膜，该薄膜可以由小于10 V的电压控制。溶液，溶液密度和自旋座椅旋转速率的最佳条件是通过许多测试选择的。结果，获得了220 nm的薄膜，该薄膜厚度表现出了铁电D-E磁滞。该膜可以用作整体电路中的内存。但是，需要更高质量的膜（包括较高有序的晶体）才能制造真实的记忆，因为与在厚度超过1μmm的膜中观察到的相比，上述的亚微米膜中观察到的极化逆转开关过程并不清楚。回忆有三个基本动作的写作，阅读和初始化。关于阅读，我们研究了样品膜光学传输的变化是否可以用于记忆的切换过程，以便将其用作光学电路的内存。我们摄入了由VDF/TRFE共聚物和列液晶5CB组成的PDLC（聚合物分散的液晶）作为样品。通过将外部电场应用于PDLC，将P（VDF/TRFE）的极化定向。源自铁电偏振的内部电场影响了液晶5CB的分子方向，并改变了PDLC的光学传输。该结果表明，光传输的变化可用于PDLC存储器的阅读机理。从这些结果我们包括可以使用聚合物的铁电特性获得有机薄膜存储器。