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Thin-Film Transistors (thin-film + transistor)
Kinds of Thin-Film Transistors Selected AbstractsUltrathin, Organic, Semiconductor/Polymer Blends by Scanning Corona-Discharge Coating for High-Performance Organic Thin-Film TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Hee Joon Jung Abstract A new thin-film coating process, scanning corona-discharge coating (SCDC), to fabricate ultrathin tri-isopropylsilylethynyl pentacene (TIPS-PEN)/amorphous-polymer blend layers suitable for high-performance, bottom-gate, organic thin-film transistors (OTFTs) is described. The method is based on utilizing the electrodynamic flow of gas molecules that are corona-discharged at a sharp metallic tip under a high voltage and subsequently directed towards a bottom electrode. With the static movement of the bottom electrode, on which a blend solution of TIPS-PEN and an amorphous polymer is deposited, SCDC provides an efficient route to produce uniform blend films with thicknesses of less than one hundred nanometers, in which the TIPS-PEN and the amorphous polymer are vertically phase-separated into a bilayered structure with a single-crystalline nature of the TIPS-PEN. A bottom-gate field-effect transistor with a blend layer of TIPS-PEN/polystyrene (PS) (90/10 wt%) operated at ambient conditions, for example, indeed exhibits a highly reliable device performance with a field-effect mobility of approximately 0.23 cm2 V,1 s,1: two orders of magnitude greater than that of a spin-coated blend film. SCDC also turns out to be applicable to other amorphous polymers, such as poly(, -methyl styrene) and poly(methyl methacrylate) and, readily combined with the conventional transfer-printing technique, gives rise to micropatterned arrays of TIPS-PEN/polymer films. [source] Fully Transparent Non-volatile Memory Thin-Film Transistors Using an Organic Ferroelectric and Oxide Semiconductor Below 200,°CADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Sung-Min Yoon Abstract A fully transparent non-volatile memory thin-film transistor (T-MTFT) is demonstrated. The gate stack is composed of organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and oxide semiconducting Al-Zn-Sn-O (AZTO) layers, in which thin Al2O3 is introduced between two layers. All the fabrication processes are performed below 200,°C on the glass substrate. The transmittance of the fabricated device was more than 90% at the wavelength of 550,nm. The memory window obtained in the T-MTFT was 7.5,V with a gate voltage sweep of ,10 to 10,V, and it was still 1.8,V even with a lower voltage sweep of ,6 to 6,V. The field-effect mobility, subthreshold swing, on/off ratio, and gate leakage currents were obtained to be 32.2,cm2 V,1 s,1, 0.45,V decade,1, 108, and 10,13 A, respectively. All these characteristics correspond to the best performances among all types of non-volatile memory transistors reported so far, although the programming speed and retention time should be more improved. [source] Transistor Paint: Environmentally Stable N -alkyldithienopyrrole and Bithiazole-Based Copolymer Thin-Film Transistors Show Reproducible High Mobilities without AnnealingADVANCED FUNCTIONAL MATERIALS, Issue 21 2009Junying Liu Abstract New solution processable 4-(2-hexyldecan)- 4H -bisthieno[2,3- d:3,,2,- b]pyrrole and 4,4,-dialkyl-2,2,-bithiazole-based copolymers (PBTzDTPs) are synthesized with excellent FET performance. These novel copolymers have considerable potential in printable electronics as they have high charge carrier mobilities, excellent air stability, good solution processibility, and no requirement for post-deposition thermal annealing, all requirements for this field of application. The thin film transistors fabricated from PBTzDTPs achieve field effect mobilities as high as 0.14,cm2 V,1 s,1 with current on/off ratios up to 106 without thermal annealing. In addition, the devices exhibit stable performance in air, showing no significant degradation over 60 days. Moreover, the polymers described here provide an excellent example of the systems in which higher mobility performance does not require higher crystalline, long-range ordered structures. Such a system appears to be particularly promising for rapid fabrication techniques, where kinetic conditions usually prevent the development of long-range order. [source] Solubility-Induced Ordered Polythiophene Precursors for High-Performance Organic Thin-Film TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Yeong Don Park Abstract With the aim of enhancing the field-effect mobility of self-assembled regioregular poly(3-hexylthiophene), P3HT, by promoting two-dimensional molecular ordering, the organization of the P3HT in precursor solutions is transformed from random-coil conformation to ordered aggregates by adding small amounts of the non-solvent acetonitrile to the solutions prior to film formation. The ordering of the precursor in the solutions significantly increases the crystallinity of the P3HT thin films. It is found that with the appropriate acetonitrile concentration in the precursor solution, the resulting P3HT nanocrystals adopt a highly ordered molecular structure with a field-effect mobility dramatically improved by a factor of approximately 20 depending on the P3HT concentration. This improvement is due to the change in the P3HT organization in the precursor solution from random-coil conformation to an ordered aggregate structure as a result of the addition of acetonitrile. In the good solvent chloroform, the P3HT molecules are molecularly dissolved and adopt a random-coil conformation, whereas upon the addition of acetonitrile, which is a non-solvent for aromatic backbones and alkyl side chains, 1D or 2D aggregation of the P3HT molecules occurs depending on the P3HT concentration. This state minimizes the unfavorable interactions between the poorly soluble P3HT and the acetonitrile solvent, and maximizes the favorable ,,, stacking interactions in the precursor solution, which improves the molecular ordering of the resulting P3HT thin film and enhances the field-effect mobility without post-treatment. [source] Thin-Film Transistors: Transparent Photo-Stable Complementary Inverter with an Organic/Inorganic Nanohybrid Dielectric Layer (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Mater. On page 726, Minsuk Oh and co-workers describe the fabrication of a transparent complementary thin-film transistor inverter with a ZnO top gate and bottom gate of pentacene channels. Twelve nanometer-thin organic,inorganic hybrid dielectric layers with high capacitance are adopted to allow the ZnO and pentacene transistors to operate under only 3 V, and the inverter action appears very stable even under a few mW of white light. This discovery could herald the arrival of a new type of transparent logic device. [source] Surface-Modified High- k Oxide Gate Dielectrics for Low-Voltage High-Performance Pentacene Thin-Film Transistors,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2007S. Kim Abstract In this study, pentacene thin-film transistors (TFTs) operating at low voltages with high mobilities and low leakage currents are successfully fabricated by the surface modification of the CeO2,SiO2 gate dielectrics. The surface of the gate dielectric plays a crucial role in determining the performance and electrical reliability of the pentacene TFTs. Nearly hysteresis-free transistors are obtained by passivating the devices with appropriate polymeric dielectrics. After coating with poly(4-vinylphenol) (PVP), the reduced roughness of the surface induces the formation of uniform and large pentacene grains; moreover, ,OH groups on CeO2,SiO2 are terminated by C6H5, resulting in the formation of a more hydrophobic surface. Enhanced pentacene quality and reduced hysteresis is observed in current,voltage (I,V) measurements of the PVP-coated pentacene TFTs. Since grain boundaries and ,OH groups are believed to act as electron traps, an OH-free and smooth gate dielectric leads to a low trap density at the interface between the pentacene and the gate dielectric. The realization of electrically stable devices that can be operated at low voltages makes the OTFTs excellent candidates for future flexible displays and electronics applications. [source] Enhancement of Interconnectivity in the Channels of Pentacene Thin-Film Transistors and Its Effect on Field-Effect Mobility,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2006S. Lee Abstract With the aim of improving the field-effect mobility of transistors by promoting the interconnectivity of the grains in pentacene thin films, deposition conditions of the pentacene molecules using one-step (total thickness of layer 50,nm: 0.1,Å,s,1) and two-step (first layer 10,nm: 0.1,Å,s,1, second layer 40,nm: 4.0,Å,s,1) depositions are controlled. Significantly, it is found that the continuities of the pentacene thin films vary with the deposition conditions of the pentacene molecules. Specifically, a smaller number of voids is observed at the interface for the two-step deposition, which results in field-effect mobilities as high as 1.2,cm2,V,1,s,1; these are higher by more than a factor of two than those of the pentacene films deposited in one step. This remarkable increase in field-effect mobility is due in particular to the interconnectivity of the pentacene grains near the insulator substrate. [source] 2,7-Carbazolenevinylene-Based Oligomer Thin-Film Transistors: High Mobility Through Structural Ordering,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2005N. Drolet Abstract We have fabricated organic field-effect transistors based on thin films of 2,7-carbazole oligomeric semiconductors 1,4-bis(vinylene-(N -hexyl-2-carbazole))phenylene (CPC), 1,4-bis(vinylene-(N,-methyl-7,-hexyl-2,-carbazole))benzene (RCPCR), N -hexyl-2,7-bis(vinylene-(N -hexyl-2-carbazole))carbazole (CCC), and N -methyl-2,7-bis(vinylene-(7-hexyl- N -methyl-2-carbazole))carbazole (RCCCR). The organic semiconductors are deposited by thermal evaporation on bare and chemically modified silicon dioxide surfaces (SiO2/Si) held at different temperatures varying from 25 to 200,°C during deposition. The resulting thin films have been characterized using UV-vis and Fourier-transform infrared spectroscopies, scanning electron microscopy, and X-ray diffraction, and the observed top-contact transistor performances have been correlated with thin-film properties. We found that these new ,-conjugated oligomers can form highly ordered structures and reach high hole mobilities. Devices using CPC as the active semiconductor have exhibited mobilities as high as 0.3,cm2,V,1,s,1 with on/off current ratios of up to 107. These features make CPC and 2,7-carbazolenevinylene-based oligomers attractive candidates for device applications. [source] Flexible Electronics: Fully Flexible Solution-Deposited ZnO Thin-Film Transistors (Adv. Mater.ADVANCED MATERIALS, Issue 38 201038/2010) Solution-processed ,real' flexible ZnO thin-film transistors (TFTs) on plastic substrates are demonstrated on p. 4308 by Jooho Moon and co-workers. The flexible device shows exceptional and unprecedented stability against various stresses such as bending, rolling, wearing, and folding, exhibiting no degradation at tensile strains up to 6.35%. Such solution processable semiconductor devices can be used to realize transparent, flexible electronic devices. [source] Fully Flexible Solution-Deposited ZnO Thin-Film TransistorsADVANCED MATERIALS, Issue 38 2010Keunkyu Song Solution-processed, fully flexible ZnO thin-film transistors (TFTs) on semitransparent substrates are demonstrated. Our devices show exceptional and unprecedented stablity against various bending stresses, i.e., bending, rolling, wearing, and folding, exhibiting no degradation at tensile strains up to 6.35%. [source] Induced Crystallization of Rubrene in Thin-Film TransistorsADVANCED MATERIALS, Issue 30 2010Zhefeng Li The poor crystallinity of rubrene in thin films is an obstacle limiting its practical applications in organic electronics. Here we report a strategy of using 6,13-pentacenequinone (PQ), an easily crystallized insulating molecule, as the template layer to induce the crystallization of rubrene in vacuum-deposited thin film transistors. This strategy relies on the bilayer steps of octadecylphosphonic acid, which play a unique role in modulating the morphology of PQ. [source] High-Performance Flexible Transparent Thin-Film Transistors Using a Hybrid Gate Dielectric and an Amorphous Zinc Indium Tin Oxide ChannelADVANCED MATERIALS, Issue 21 2010Jun Liu High-performance flexible transparent thin-film transistors (TFTs) are demonstrated using amorphous zink indium tin oxide (ZITO) transparent oxide conductor electrodes, an amorphous ZITO transparent oxide semiconductor channel, and a vapor-deposited self-assembled nanodielectric (v-SAND) gate insulator. These TFTs exhibit a large field-effect mobility of 110 cm2V,1s,1, a current on/off ratio of 104, and a low operating voltage of 1.0,V, along with very good optical transparency and mechanical flexibility. [source] Recent Progress in n-Channel Organic Thin-Film TransistorsADVANCED MATERIALS, Issue 12 2010Yugeng Wen Abstract Particular attention has been focused on n-channel organic thin-film transistors (OTFTs) during the last few years, and the potentially cost-effective circuitry-based applications in flexible electronics, such as flexible radiofrequency identity tags, smart labels, and simple displays, will benefit from this fast development. This article reviews recent progress in performance and molecular design of n-channel semiconductors in the past five years, and limitations and practicable solutions for n-channel OTFTs are dealt with from the viewpoint of OTFT constitution and geometry, molecular design, and thin-film growth conditions. Strategy methodology is especially highlighted with an aim to investigate basic issues in this field. [source] Microstructural Origin of High Mobility in High-Performance Poly(thieno-thiophene) Thin-Film TransistorsADVANCED MATERIALS, Issue 6 2010Chenchen Wang High-mobility PBTTT thin-film transistors are modeled with a mobility edge model and compared with P3HT. Their improved performance is not due to a low trap density but rather due to high mobility in the crystallites. Characterization of delaminated films with transmission electron microscopy and atomic force microscopy indicates terraces that are composed of nanometer-scale features (see figure). [source] Organic Thin-Film Transistors Fabricated on Resorbable Biomaterial SubstratesADVANCED MATERIALS, Issue 5 2010Christopher J. Bettinger Organic electronics and biodegradable materials have the potential to be integrated to create a new class of electronic devices for the use in biomedical and environmental applications. Organic thin-film field-effect transistors fabricated using a biodegradable material platform exhibit water stable performance and degrade in vitro. [source] High-Mobility Nonvolatile Memory Thin-Film Transistors with a Ferroelectric Polymer Interfacing ZnO and Pentacene ChannelsADVANCED MATERIALS, Issue 42 2009Kwang H. Lee Nonvolatile memory ferroelectric thin-film transistors (FeTFT) with P(VDF-TrFE) polymer are demonstrated with both n-channel ZnO and p-channel pentacene. A high mobility of ,1,cm2 V,1 s,1 and large memory window of ,20,V are achieved through the organic ferroelectric, inorganic channel hybrid device of ZnO-FeTFT. WRITE/ERASE states are clearly distinguished by ±20,V switching for ZnO- and pentacene-FeTFTs. [source] Organic Thin-Film Transistors: Controlling Nucleation and Crystallization in Solution-Processed Organic Semiconductors for Thin-Film Transistors (Adv. Mater.ADVANCED MATERIALS, Issue 35 200935/2009) The grain size in solution-processed organic semiconductor thin films for TFTs can be tuned over a range of three orders of magnitude, report Yueh-Lin Loo and co-workers on p. 3605. The process involves the addition of fractional quantities of "impurities" that are capable of seeding the crystallization of the organic semiconductor, and the control thus exerted permitted studies that correlated increasing device mobility with increasing grain size. [source] Controlling Nucleation and Crystallization in Solution-Processed Organic Semiconductors for Thin-Film TransistorsADVANCED MATERIALS, Issue 35 2009Stephanie S. Lee Three orders of magnitude is the range over which the grain size (see figure) can be tuned in solution-processed organic semiconductor thin films for TFTs. Fluorinated triethylsilyl anthradithiophene (FTES-ADT) is added in fractional amounts to seed crystallization of TES-ADT. Correlation between device mobility and grain size in the active layer is described by a composite mobility model that assumes charge-carrier traps are located at grain boundaries. [source] A New Poly(thienylenevinylene) Derivative with High Mobility and Oxidative Stability for Organic Thin-Film Transistors and Solar CellsADVANCED MATERIALS, Issue 27 2009Bogyu Lim A novel thiophene-thienylenevinylene copolymer is synthesized and evaluated for use in organic field-effect transistors and organic solar cells. PETV12T shows good solution processability and high structural organization after annealing. Organic thin-film transistors based on the polymer exhibit high mobility and a high resistance to oxidation. In addition, PETV12T shows potential as an electron donor in bulk heterojunction solar cells. [source] Improvements in Stability and Performance of N,N, -Dialkyl Perylene Diimide-Based n-Type Thin-Film TransistorsADVANCED MATERIALS, Issue 16 2009Yugeng Wen The stability and performance of N,N, -dioctyl perylene diimide (PDI-C8) and N,N, -ditridecyl perylene diimide (PDI-C13) thin-film transistors (TFTs) are increased using optimized growth rates and sulfur-modified top-contact electrodes. Changing the grain size and the depth of grain boundaries by controlling film growth rate is another way of increasing the air stability of perylene diimides without electron-withdrawing groups. [source] Utilizing Highly Crystalline Pyroelectric Material as Functional Gate Dielectric in Organic Thin-Film TransistorsADVANCED MATERIALS, Issue 8 2009Nguyen Thanh Tien Highly crystalline P(VDF-TrFE) materials have a large remnant polarization that causes the ID,VD curves to have no current saturation in the region where they normally would. This high crystallinity also results in a positive pyroelectricity, which is different from the conventional low response and nonlinear negative pyroelectricity. [source] Fully Transparent Thin-Film Transistors Based on Aligned Carbon Nanotube Arrays and Indium Tin Oxide Electrodes,ADVANCED MATERIALS, Issue 5 2009Sunkook Kim Fully transparent thin-film transistors (TFTs) based on well-aligned single-walled carbon nanotube (SWCNT) arrays with indium tin oxide (ITO) electrodes are achieved. The fully transparent SWCNT-TFTs could be attractive candidates for future flexible or transparent electronics. [source] Versatile Use of Vertical-Phase-Separation-Induced Bilayer Structures in Organic Thin-Film Transistors,ADVANCED MATERIALS, Issue 6 2008Longzhen Qiu A semiconductor-top and dielectric-bottom bilayer structure is fabricated by surface-induced vertical phase separation of poly(3-hexylthiophene) (P3HT) and poly(methyl methacrylate) (PMMA) blends (see figure). This structure allows to prepare high-performance, low-semiconductor-content, and low-voltage-driven TFTs in a very effective method, in which the dielectric and semiconductor layers are deposited onto a substrate in a one-step process. [source] Highly Bendable, Transparent Thin-Film Transistors That Use Carbon-Nanotube-Based Conductors and Semiconductors with Elastomeric Dielectrics,ADVANCED MATERIALS, Issue 3 2006Q. Cao Transparent flexible thin-film transistors (see Figure) have been made using single-walled carbon nanotube networks of high and moderate coverages as the conducting and semiconducting layers. Electrical (e.g., good performance on plastic), optical (e.g. transparency to visible wavelengths), and mechanical (e.g. extreme flexibility) characteristics that would be difficult, or impossible, to achieve with conventional materials are reported. [source] Thickness Dependence of Mobility in Pentacene Thin-Film Transistors,ADVANCED MATERIALS, Issue 14 2005R. Ruiz The field-effect mobility of pentacene transistors saturates when six,monolayers of pentacene are deposited on the gate dielectric. This saturation is not caused by the formation of islands, as the early stages of growth have been found to take place in a layer-by-layer fashion, and layer completion continues well past six,monolayers (see Figure). [source] Functionalized Arylacetylene Oligomers for Organic Thin-Film Transistors (OTFTs),ADVANCED MATERIALS, Issue 10 2005Oligo(arylacetylene)-based organic thin-film transistors (OTFTs) possess good structural order and smooth film morphologies, and exhibit field-effect mobilities of 0.3,cm2,V,1,s,1, one of the highest field-effect mobilities reported for an OTFT device that does not possess a self-assembled-layer configuration. The Figure shows the measured output characteristics (drain,source current, IDS versus drain,source voltage, VDS) at different gate voltages (VG). [source] Self-Organized Organic Thin-Film Transistors on Plastic,ADVANCED MATERIALS, Issue 8 2004Y. Choi The development of the self-organized growth of pentacence thin films on the channel region of a thin-film transistor (TFT) using surface modifications induced by organic vapor phase deposition is reported (see Figure). A bottom-contact TFT on plastic using an organic gate insulator of cross-linked poly-(4-vinylphenol) exhibited a field-effect mobility of 1.2 cm2/Vs and an on/off current ratio of ,,107. [source] Performance of thin-film transistors fabricated by sequential lateral solidification crystallization techniquesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008M. A. Exarchos Abstract The performance of Excimer Laser Annealed (ELA) Thin-Film Transistors (TFTs), in terms of drain current behaviour in unstressed as well as in DC stressed devices, is presented. The transistors studied were fabricated under different irradiation schemes of a novel Sequential Lateral Solidification (SLS) process. As far as unstressed transistors concerned, drain current transients relaxed through stretched exponential law. Fitting results disclosed that both gate dielectric polarization and carrier recombination mechanisms occurred through transient relaxation. Deep Level Transient Spectroscopy (DLTS) technique was called forth in order to investi- gate the origin of carrier recombination mechanisms. DC hot carrier stress measurements, under "worst ageing condition" regime, were conducted in order to probe degradation mechanisms and device reliability standards. Crystal domain size significantly affects threshold voltage degradation. The latter increases with decreasing crystal domain size, due to increased concentration of protrusions in the polysilicon film. Transconductance degradation also depends on crystal domain size, attributed mainly to bulk polysilicon trap generation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] New Soluble Pentacene Precursors for the Application of Organic Thin-Film Transistors.CHEMINFORM, Issue 16 2004Kyung Soo Suh Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Cruciform 6,6,-Dipentacenyl: Synthesis, Solid-State Packing and Applications in Thin-Film TransistorsCHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2010Xiaojie Zhang Dr. No abstract is available for this article. [source] | ||||||||||||||||