Title
Retention time and depolarization in organic nonvolatile memories based on ferroelectric semiconductor phase-separated blends
Author
Asadi, K.
Wildeman, J.
Blom, P.W.M.
de Leeuw, D.M.
TNO Industrie en Techniek
Publication year
2010
Abstract
Resistive switches have been fabricated using a phase-separated blend film of ferroelectric random copolymer poly(vinylidene fluoride-co-trifluoroethylene) with the organic semiconductor regio-irregular poly(3-hexylthiophene) (rir-P3HT). Spin-coated blend films have been contacted with symmetrical Ag top and Ag bottom electrodes, yielding switching diodes. The ferroelectric polarization modulates the injection barrier, yielding an injection-limited off-state and a space-charge-limited on -state. To study the effect of depolarization, an additional polyphenylenevinylene-type semiconductor layer with the highest occupied molecular orbital energy that is comparable to that of rir-P3HT has been inserted in the diode stack. When the ad-layer is the injecting contact, the current modulation ratio goes to unity. The origin is a decrease in the effective band bending at the contact with increasing ad-layer thickness. When the counter electrode at the blend interface is the injecting contact, the diode can be switched, but the on-state is only stable when an electric field that is larger than the coercive field is applied. Upon field removal, the ferroelectric depolarizes, and the current drops to that of an unpoled pristine diode. The depolarization is confirmed by capacitancevoltage and retention time measurements. To realize bistable diodes with excellent retention times, the thickness of the semiconducting wetting layer may not be at most 10 nm. © 2006 IEEE.
Subject
Mechatronics, Mechanics & Materials
HOL - Holst
TS - Technical Sciences
High Tech Systems & Materials
Electronics
Industrial Innovation
Depolarization
Bandbending
Bistables
Blend films
Bottom electrodes
Capacitance voltage
Coercive field
Counter electrodes
Current modulation
Diode stacks
Ferroelectric polarization
Ferroelectric semiconductors
Highest occupied molecular orbital
Injection barriers
Layer thickness
Non-volatile memories
Organic nonvolatile memories
Organic semiconductor
Poly (3-hexylthiophene)
Random copolymer
Retention time
Semiconductor layers
Space-charge-limited
Switching diodes
Trifluoroethylene
Vinylidene fluoride
Wetting layer
Depolarization
Electric fields
Ferroelectricity
Molecular orbitals
Organic polymers
Switching systems
Time measurement
Semiconductor diodes
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http://resolver.tudelft.nl/uuid:c1300edb-2fc3-4e9f-b9f6-fda89933ac57
TNO identifier
461515
ISSN
0018-9383
Source
IEEE Transactions on Electron Devices, 57 (12), 3466-3471
Article number
No.: 5582274
Document type
article