Thin ferroelectric poly(vinylidene fluoride-chlorotrifluoro ethylene) films for thermal history independent non-volatile polymer memory

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• 作者：Richard Hahnkee Kim ; Seok Ju Kang ; Insung Bae ; Yeon Sik Choi ; Youn Jung Park ; Cheolmin Park ; ^{cmpark@yonsei.ac.kr}
• 关键词：Ferroelectric polymer ; Poly(vinylidene fluoride-chlorotrifluoro ethylene) ; Crystal phase ; Remnant polarization ; Non-volatile polymer memory ; Ferroelectric capacitor
• 刊名：Organic Electronics
• 出版年：2012
• 出版时间：March 2012
• 年：2012
• 卷：13
• 期：3
• 页码：491-497
• 全文大小：910 K

文摘

In this study, we investigated the molecular and microstructures of thin poly(vinylidene fluoride-chlorotrifluoro ethylene) (PVDF-CTFE) copolymer films with three different CTFE compositions of 10, 15, 20 wt % with respect to PVDF in relation with their ferroelectric properties. All PVDF-CTFE annealed at 130 ¡ãC showed consecutive TTTT trans conformation with ¦Â type crystals while films molten and re-crystallized from a temperature above their melting points exhibited ¦Á type crystals with characteristic TGTG conformation. Microstructures of the films treated with the two different thermal histories also supported the formation of ¦Â and ¦Á type crystals with hundreds of nanometer scale sphere caps and micron level spherulites, respectively. Interestingly, PVDF-CTFE films with both ¦Á and ¦Â type crystals gave rise to relatively high remnant polarization of approximately 4 ¦ÌC/cm² in metal/ferroelectric/metal capacitors regardless of the composition of CTFE. The ferroelectric polarization of a PVDF-CTFE film independent of thermal processing history allowed a wide processing window and easy fabrication protocol, resulting in a non-volatile ferroelectric field effect transistor memory which exhibited saturated hysteresis loops with the current ON/OFF ratio of approximately 10³ at ¡À60 V sweep and reliable data retention.