Abstract
We herein report on the nonvolatile memory properties of iron phthalocyanine multilayers prepared using an electrostatic layer-by-layer assembly method. Cationic poly(allylamine hydrochloride) (PAH) and anionic iron(III) phthalocyanine-4, 4,′ 4″, 4‴-tetrasulfonic acid (Fe-TsPc) were alternately deposited onto quartz glass, indium tin oxide (ITO), or platinum-coated silicon substrates via electrostatic interactions. The electrochemical response of the PAH/Fe-TsPc, which was obtained from cyclic voltammograms (CV) in solution, indicated that redox reactions occurred at the phthalocyanine unit and at the metallic center. It was found that these redox reactions of the PAH/Fe-TsPc multilayer films in solution could be extended to resistive switching nonvolatile memory based on a charge trap/release mechanism in air. The PAH/Fe-TsPc multilayers sandwiched between the bottom (platinum) and top (Ag or tungsten) electrodes exhibited the characteristics of a resistive switching memory at a relatively low operating voltage of less than 2 V, with a switching speed of about 100 ns and an ON/OFF current ratio of ∼10 3. Additionally, it is confirmed using kelvin probe force microscopy (KPFM) that the reversible resistance changes in the PAH/Fe-TsPc multilayers are mainly caused by the externally applied voltage as a result of the trapping and release of charges at redox sites within the Fe-TsPc. Furthermore, in the case where insulating layers of about 2 nm in thickness are inserted between adjacent Fe-TsPc layers, it is demonstrated that these devices can exhibit further improvements in memory performance (ON/OFF current ratio of ∼10 6) and a lower power consumption in comparison with PAH/Fe-TsPc multilayers.
| Original language | English |
|---|---|
| Pages (from-to) | 1091-1099 |
| Number of pages | 9 |
| Journal | Chemistry of Materials |
| Volume | 24 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2012 Mar 27 |
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ASJC Scopus subject areas
- Materials Chemistry
- Chemical Engineering(all)
- Chemistry(all)
Cite this
Control over memory performance of layer-by-layer assembled metal phthalocyanine multilayers via molecular-level manipulation. / Koo, Bonkee; Baek, Hyunhee; Cho, Jinhan.
In: Chemistry of Materials, Vol. 24, No. 6, 27.03.2012, p. 1091-1099.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Control over memory performance of layer-by-layer assembled metal phthalocyanine multilayers via molecular-level manipulation
AU - Koo, Bonkee
AU - Baek, Hyunhee
AU - Cho, Jinhan
PY - 2012/3/27
Y1 - 2012/3/27
N2 - We herein report on the nonvolatile memory properties of iron phthalocyanine multilayers prepared using an electrostatic layer-by-layer assembly method. Cationic poly(allylamine hydrochloride) (PAH) and anionic iron(III) phthalocyanine-4, 4,′ 4″, 4‴-tetrasulfonic acid (Fe-TsPc) were alternately deposited onto quartz glass, indium tin oxide (ITO), or platinum-coated silicon substrates via electrostatic interactions. The electrochemical response of the PAH/Fe-TsPc, which was obtained from cyclic voltammograms (CV) in solution, indicated that redox reactions occurred at the phthalocyanine unit and at the metallic center. It was found that these redox reactions of the PAH/Fe-TsPc multilayer films in solution could be extended to resistive switching nonvolatile memory based on a charge trap/release mechanism in air. The PAH/Fe-TsPc multilayers sandwiched between the bottom (platinum) and top (Ag or tungsten) electrodes exhibited the characteristics of a resistive switching memory at a relatively low operating voltage of less than 2 V, with a switching speed of about 100 ns and an ON/OFF current ratio of ∼10 3. Additionally, it is confirmed using kelvin probe force microscopy (KPFM) that the reversible resistance changes in the PAH/Fe-TsPc multilayers are mainly caused by the externally applied voltage as a result of the trapping and release of charges at redox sites within the Fe-TsPc. Furthermore, in the case where insulating layers of about 2 nm in thickness are inserted between adjacent Fe-TsPc layers, it is demonstrated that these devices can exhibit further improvements in memory performance (ON/OFF current ratio of ∼10 6) and a lower power consumption in comparison with PAH/Fe-TsPc multilayers.
AB - We herein report on the nonvolatile memory properties of iron phthalocyanine multilayers prepared using an electrostatic layer-by-layer assembly method. Cationic poly(allylamine hydrochloride) (PAH) and anionic iron(III) phthalocyanine-4, 4,′ 4″, 4‴-tetrasulfonic acid (Fe-TsPc) were alternately deposited onto quartz glass, indium tin oxide (ITO), or platinum-coated silicon substrates via electrostatic interactions. The electrochemical response of the PAH/Fe-TsPc, which was obtained from cyclic voltammograms (CV) in solution, indicated that redox reactions occurred at the phthalocyanine unit and at the metallic center. It was found that these redox reactions of the PAH/Fe-TsPc multilayer films in solution could be extended to resistive switching nonvolatile memory based on a charge trap/release mechanism in air. The PAH/Fe-TsPc multilayers sandwiched between the bottom (platinum) and top (Ag or tungsten) electrodes exhibited the characteristics of a resistive switching memory at a relatively low operating voltage of less than 2 V, with a switching speed of about 100 ns and an ON/OFF current ratio of ∼10 3. Additionally, it is confirmed using kelvin probe force microscopy (KPFM) that the reversible resistance changes in the PAH/Fe-TsPc multilayers are mainly caused by the externally applied voltage as a result of the trapping and release of charges at redox sites within the Fe-TsPc. Furthermore, in the case where insulating layers of about 2 nm in thickness are inserted between adjacent Fe-TsPc layers, it is demonstrated that these devices can exhibit further improvements in memory performance (ON/OFF current ratio of ∼10 6) and a lower power consumption in comparison with PAH/Fe-TsPc multilayers.
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U2 - 10.1021/cm2033959
DO - 10.1021/cm2033959
M3 - Article
AN - SCOPUS:84859127514
VL - 24
SP - 1091
EP - 1099
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 6
ER -