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Polymer Field-effect Transistors (polymer + field-effect_transistor)
Selected AbstractsIntegration of a Rib Waveguide Distributed Feedback Structure into a Light-Emitting Polymer Field-Effect TransistorADVANCED FUNCTIONAL MATERIALS, Issue 11 2009Michael C. Gwinner No abstract is available for this article. [source] Integration of a Rib Waveguide Distributed Feedback Structure into a Light-Emitting Polymer Field-Effect TransistorADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Michael C. Gwinner Abstract Ambipolar light-emitting organic field-effect transistors (LEFETs) possess the ability to efficiently emit light due to charge recombination in the channel. Since the emission can be made to occur far from the metal electrodes, the LEFET structure has been proposed as a potential architecture for electrically pumped organic lasers. Here, a rib waveguide distributed feedback structure consisting of tantalum pentoxide (Ta2O5) integrated within the channel of a top gate/bottom contact LEFET based on poly(9,9-dioctylfluorene- alt -benzothiadiazole) (F8BT) is demonstrated. The emitted light is coupled efficiently into the resonant mode of the DFB waveguide when the recombination zone of the LEFET is placed directly above the waveguide ridge. This architecture provides strong mode confinement in two dimensions. Mode simulations are used to optimize the dielectric thickness and gate electrode material. It is shown that electrode absorption losses within the device can be eliminated and that the lasing threshold for optical pumping of the LEFET structure with all electrodes (4.5,µJ cm,2) is as low as that of reference devices without electrodes. These results enable quantitative judgement of the prospects for realizing an electrically pumped organic laser based on ambipolar LEFETs. The proposed device provides a powerful, low-loss architecture for integrating high-performance ambipolar organic semiconductor materials into electrically pumped lasing structures. [source] Controllable Shifts in Threshold Voltage of Top-Gate Polymer Field-Effect Transistors for Applications in Organic Nano Floating Gate MemoryADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Kang-Jun Baeg Abstract Organic field-effect transistor (FET) memory is an emerging technology with the potential to realize light-weight, low-cost, flexible charge storage media. Here, solution-processed poly[9,9-dioctylfluorenyl-2,7-diyl]-co-(bithiophene)] (F8T2) nano floating gate memory (NFGM) with a top-gate/bottom-contact device configuration is reported. A reversible shift in the threshold voltage (VTh) and reliable memory characteristics was achieved by the incorporation of thin Au nanoparticles (NPs) as charge storage sites for negative charges (electrons) at the interface between polystyrene and cross-linked poly(4-vinylphenol). The F8T2 NFGM showed relatively high field-effect mobility (µFET) (0.02,cm2 V,1 s,1) for an amorphous semiconducting polymer with a large memory window (ca. 30,V), a high on/off ratio (more than 104) during writing and erasing with an operation voltage of 80,V of gate bias in a relatively short timescale (less than 1,s), and a retention time of a few hours. This top-gated polymer NFGM could be used as an organic transistor memory element for organic flash memory. [source] Polymer Field-Effect Transistors Fabricated by the Sequential Gravure Printing of Polythiophene, Two Insulator Layers, and a Metal Ink GateADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Monika M. Voigt Abstract The mass production technique of gravure contact printing is used to fabricate state-of-the art polymer field-effect transistors (FETs). Using plastic substrates with prepatterned indium tin oxide source and drain contacts as required for display applications, four different layers are sequentially gravure-printed: the semiconductor poly(3-hexylthiophene-2,5-diyl) (P3HT), two insulator layers, and an Ag gate. A crosslinkable insulator and an Ag ink are developed which are both printable and highly robust. Printing in ambient and using this bottom-contact/top-gate geometry, an on/off ratio of >104 and a mobility of 0.04,cm2 V,1 s,1 are achieved. This rivals the best top-gate polymer FETs fabricated with these materials. Printing using low concentration, low viscosity ink formulations, and different P3HT molecular weights is demonstrated. The printing speed of 40,m min,1 on a flexible polymer substrate demonstrates that very high-volume, reel-to-reel production of organic electronic devices is possible. [source] Charge Transport Physics of Conjugated Polymer Field-Effect TransistorsADVANCED MATERIALS, Issue 34 2010Henning Sirringhaus Abstract Field-effect transistors based on conjugated polymers are being developed for large-area electronic applications on flexible substrates, but they also provide a very useful tool to probe the charge transport physics of these complex materials. In this review we discuss recent progress in polymer semiconductor materials, which have brought the performance and mobility of polymer devices to levels comparable to that of small-molecule organic semiconductors. These new materials have also enabled deeper insight into the charge transport physics of high-mobility polymer semiconductors gained from experiments with high charge carrier concentration and better molecular-scale understanding of the electronic structure at the semiconductor/dielectric interface. [source] Plastic Electronics: The Influence of Morphology on High-Performance Polymer Field-Effect Transistors (Adv. Mater.ADVANCED MATERIALS, Issue 2 20092/2009) On p. 209, Wojciech Pisula, Klaus Müllen, and co-workers report on directionally oriented, high-performance polymer field-effect transistors for plastic electronics. The cover shows the applied alignment from solution, resulting in pronounced macroscopic ordering of the copolymer chains and finally in excellent transistor behavior, which is promising for applications in, for example, flexible displays. [source] The Influence of Morphology on High-Performance Polymer Field-Effect TransistorsADVANCED MATERIALS, Issue 2 2009Hoi Nok Tsao The influence of molecular packing on the performance of polymer organic field-effect transistors is illustrated in this work. Both close ,-stacking distance and long-range order are important for achieving high mobilities. By aligning the polymers from solution, long-range order is induced, yielding hole mobilities of up to µsat,=,1.4,cm2 V,1 s,1 and current on/off ratios Ion/Ioff of 105. [source] Polymer Field-Effect Transistors Fabricated by the Sequential Gravure Printing of Polythiophene, Two Insulator Layers, and a Metal Ink GateADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Monika M. Voigt Abstract The mass production technique of gravure contact printing is used to fabricate state-of-the art polymer field-effect transistors (FETs). Using plastic substrates with prepatterned indium tin oxide source and drain contacts as required for display applications, four different layers are sequentially gravure-printed: the semiconductor poly(3-hexylthiophene-2,5-diyl) (P3HT), two insulator layers, and an Ag gate. A crosslinkable insulator and an Ag ink are developed which are both printable and highly robust. Printing in ambient and using this bottom-contact/top-gate geometry, an on/off ratio of >104 and a mobility of 0.04,cm2 V,1 s,1 are achieved. This rivals the best top-gate polymer FETs fabricated with these materials. Printing using low concentration, low viscosity ink formulations, and different P3HT molecular weights is demonstrated. The printing speed of 40,m min,1 on a flexible polymer substrate demonstrates that very high-volume, reel-to-reel production of organic electronic devices is possible. [source] High Mobility Ambipolar Charge Transport in Polyselenophene Conjugated PolymersADVANCED MATERIALS, Issue 21 2010Zhuoying Chen High mobility ambipolor polymer field-effect transistors based on a series of regioregular polyselenophenes are presented together with their morphological and optical properties. Balanced electron and hole mobilities on the order of 0.03,cm2,V,1,s,1 are observed by employing a simple top-gate/bottom-contact configuration with photolithographically defined gold source/drain contacts. High gain complementary-like voltage inverters are demonstrated based on two identical ambipolar transistors. [source] Plastic Electronics: The Influence of Morphology on High-Performance Polymer Field-Effect Transistors (Adv. Mater.ADVANCED MATERIALS, Issue 2 20092/2009) On p. 209, Wojciech Pisula, Klaus Müllen, and co-workers report on directionally oriented, high-performance polymer field-effect transistors for plastic electronics. The cover shows the applied alignment from solution, resulting in pronounced macroscopic ordering of the copolymer chains and finally in excellent transistor behavior, which is promising for applications in, for example, flexible displays. [source] Observation of Field-Effect Transistor Behavior at Self-Organized Interfaces,ADVANCED MATERIALS, Issue 18 2004L.-L. Chua Ultrathin, conformal semiconductor, dielectric bilayers can be fabricated in one step by self-organization (see Figure), without exposing the critical interface to ambient contamination. Low-voltage polymer field-effect transistors using a fluorene,triarylamine copolymer as the p-channel semiconductor and 40,60 nm thick crosslinked bisbenzocyclobutene derivative as the gate dielectric are shown to be robust and reproducible. [source] Fabrication and analysis of polymer field-effect transistorsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2004S. Scheinert Abstract Parameters of organic field-effect transistors (OFET) achieved in recent years are promising enough for R & D activities towards a commercial low-cost polymer electronics. In spite of the fast progress, preparations dominated by trial and error are concentrated essentially on higher mobility polymers and shorter channel patterning, and the analysis of measured data is based on oversimplified models. Here ways to professionalize the research on polymer field-effect transistors are discussed exploiting experience accumulated in microelectronics. First of all, designing the devices before fabricating and subsequently analyzing them requires appropriate modelling. Almost independently from the nature of the transport process, the device physics is basically described by the drift-diffusion model, combined with non-degenerate carrier statistics. Therefore, with a modified interpretation of the so-called effective density of states, existing simulation tools can be applied, except for special cases which are discussed. Analytical estimates are helpful already in designing devices, and applied to experimental data they yield input parameters for the numerical simulations. Preparations of OFET's and capacitors with poly(3-ocylthiophene) (P3OT), poly(3-dodecylthiophene) P3HT, Arylamino-poly-(phenylene-vinylene) (PPV), poly(2-methoxy, 5 ethyl (2, hexyloxy) paraphenylenevinylene) MEH-PPV, and pentacene from a soluble precursor are described, with silicon dioxide (SiO2) or poly(4-vinylphenol) (P4VP) as gate insulator, and with rather different channel length. We demonstrate the advantage of combining all steps from design/fabrication to analysis of the experimental data with analytical estimates and numerical simulation. Of special importance is the connection between mobility, transistor channel length, cut-off frequency and operation voltage, which was the starting point for the development of a low-cost fabrication of high-performance submicrometer OFET's by an underetching technique. Finally results of simulation studies are presented concerning the formation of inversion layers, the influence of a trap distribution (as in the a-Si model) and of different types of source/drain contacts on top and bottom contact OFET's, and short-channel effects in submicrometer devices. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||