n-Channel Organic Thin-Film Transistors based on Naphthalene--Bis(dicarboximide) Polymer for Organic Transistor Memory Using Hole-Acceptor Layer
An investigation of threshold voltage shifts in organic thin-film transistors (OTFTs) based on poly{[ N , N $\aku '$-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt -5,5$'$-(2,2$'$-bithiophene)} [P(NDI2OD-T2)] with additional poly(3-hexylthiophene) (P3HT) fil...
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| Published in | Japanese Journal of Applied Physics Vol. 50; no. 9; pp. 091603 - 091603-4 |
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| Main Authors | , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.09.2011
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| Online Access | Get full text |
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| Summary: | An investigation of threshold voltage shifts in organic thin-film transistors (OTFTs) based on poly{[ N , N $\aku '$-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt -5,5$'$-(2,2$'$-bithiophene)} [P(NDI2OD-T2)] with additional poly(3-hexylthiophene) (P3HT) films on a poly(methyl methacrylate) (PMMA) organic dielectric layer is reported. With a top source-drain contact structure, the device exhibited a unipolar property with n-channel characteristics similar to those of the P(NDI2OD-T2)-only device. Furthermore, the existence of P3HT films as hole acceptor-like storage layers resulted in reversible $V_{\text{th}}$ shift upon the application of external gate bias ($V_{\text{bias}}$) for a certain bias time ($T_{\text{bias}}$). Hence, the P(NDI2OD-T2)/P3HT-OTFTs exhibited a large memory window ($\Delta V_{\text{th}} = 10.7$ V) for write and erase electrically without major degradation in saturation mobility [$\mu_{\text{sat}} = (1.8{\mbox{--}}2.8) \times 10^{-4}$ cm 2 V -1 s -1 ]. These results clearly indicate the utility of the naphthalene--bis(dicarboximide) (NDI)-based polymer--hole acceptor layer in the development of n-channel organic transistor memories. |
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| Bibliography: | Molecular structures of P(NDI2OD-T2), P3HT, and PMMA. Schematic diagram of top-contact-structure n-channel OTFTs. Output characteristics of P(NDI2OD-T2)-OTFTs (dashed red line) and P(NDI2OD-T2)/P3HT-OTFTs (solid black line). Semilogarithmic plots of both drain current and square root of drain current versus gate voltage showing the transfer characteristics of (a) P(NDI2OD-T2)-OTFTs and (b) P(NDI2OD-T2)/P3HT-OTFTs at a constant drain voltage of 20 V. Transfer characteristics obtained upon application of different external gate bias conditions at constant $V_{\text{ds}} = 20$ V for (a) P(NDI2OD-T2)-OTFTs with external $V_{\text{bias}} = 40$ and 60 V for $T_{\text{bias}} = 5$ min. (b) P(NDI2OD-T2)/P3HT-OTFTs with $V_{\text{bias}} = 0$ V (initial state). $V_{\text{bias}} = -60$ V was applied for $T_{\text{bias}} = 5$ min (write state), and $V_{\text{bias}} = 60$ V was applied for $T_{\text{bias}} = 5$ min (erase state). (c) Square root drain current versus gate voltage to determine mobility and threshold voltage at each initial, write, and erase operations. Schematic illustration of operating mechanism for n-channel OTFT memory using a hole-acceptor layer as the charge storage layer. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.50.091603 |