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Sample records for ambipolar organic transistors

  1. Ambipolar organic field-effect transistors on unconventional substrates

    Science.gov (United States)

    Cosseddu, P.; Mattana, G.; Orgiu, E.; Bonfiglio, A.

    2009-04-01

    In this paper we report on the realization of flexible all-organic ambipolar field-effect transistors (FETs) realized on unconventional substrates, such as plastic films and textile yarns. A double layer pentacene-C60 heterojunction was used as the semiconductor layer. The contacts were made with poly(ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) and patterned by means of soft lithography microcontact printing (μCP). Very interestingly growing C60 on a predeposited pentacene buffer layer leads to a clear improvement in the morphology and crystallinity of the film so it obtains n-type conduction despite the very high electron injection barrier at the interface between PEDOT:PSS and C60. As a result, it was possible to obtain all-organic ambipolar FETs and to optimize their electrical properties by tuning the thicknesses of the two employed active layers. Moreover, it will be shown that modifying the triple interface between dielectric/semiconductor/electrodes is a crucial point for optimizing and balancing injection and transport of both kinds of charge carriers. In particular, we demonstrate that using a middle contact configuration in which source and drain electrodes are sandwiched between pentacene and C60 layers allows significantly improving the electrical performance in planar ambipolar devices. These findings are very important because they pave the way for the realization of low-cost, fully flexible and stretchable organic complementary circuits for smart wearable and textile electronics applications.

  2. Ambipolar Organic Tri-Gate Transistor for Low-Power Complementary Electronics

    NARCIS (Netherlands)

    Torricelli, F.; Ghittorelli, M.; Smits, E.C.P.; Roelofs, C.W.S.; Janssen, R.A.J.; Gelinck, G.H.; Kovács-Vajna, Z.M.; Cantatore, E.

    2016-01-01

    Ambipolar transistors typically suffer from large off-current inherently due to ambipolar conduction. Using a tri-gate transistor it is shown that it is possible to electrostatically switch ambipolar polymer transistors from ambipolar to unipolar mode. In unipolar mode, symmetric characteristics wit

  3. BPTs: thiophene-flanked benzodipyrrolidone conjugated polymers for ambipolar organic transistors.

    Science.gov (United States)

    Rumer, Joseph W; Levick, Matthew; Dai, Sheng-Yao; Rossbauer, Stephan; Huang, Zhenggang; Biniek, Laure; Anthopoulos, Thomas D; Durrant, James R; Procter, David J; McCulloch, Iain

    2013-05-18

    A series of novel thiophene-flanked benzodipyrrolidone (BPT)-based alternating copolymers are synthesised, their optical and electrical properties evaluated. The BPT unit promotes a conjugated, planar polymer backbone, with a low bandgap, primarily due to low lying LUMO energy levels. Copolymerisation with thiophene exhibits well balanced ambipolar organic field-effect transistor performance, with electron and hole mobilities 0.1 and 0.2 cm(2) V(-1) s(-1), respectively.

  4. Ambipolar organic field effect transistors and inverters with the natural material Tyrian Purple

    Directory of Open Access Journals (Sweden)

    Eric Daniel Głowacki

    2011-12-01

    Full Text Available Ambipolar organic semiconductors enable complementary-like circuits in organic electronics. Here we show promising electron and hole transport properties in the natural pigment Tyrian Purple (6,6’-dibromoindigo. X-ray diffraction of Tyrian Purple films reveals a highly-ordered structure with a single preferential orientation, attributed to intermolecular hydrogen bonding. This material, with a band gap of ∼1.8 eV, demonstrates high hole and electron mobilities of 0.22 cm2/V·s and 0.03 cm2/V·s in transistors, respectively; and air-stable operation. Inverters with gains of 250 in the first and third quadrant show the large potential of Tyrian Purple for the development of integrated organic electronic circuits.

  5. Passivated ambipolar black phosphorus transistors.

    Science.gov (United States)

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-07-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ∼83 cm(2) V(-1) s(-1) from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ∼10 nm thick BP flake was used. PMID:27283027

  6. Passivated ambipolar black phosphorus transistors

    Science.gov (United States)

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-06-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used.We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used. Electronic supplementary information (ESI) available: Transfer characteristics of BP field effect transistors (BV1-BV4) (Fig. S1 and S2 and Table S1); output characteristics of BP field effect transistors in different directions (Fig. S3

  7. Near-Infrared Light-Emitting Ambipolar Organic Field-Effect Transistors

    NARCIS (Netherlands)

    Smits, E.C.P.; Setayesh, S.; Anthopoulos, T.D.; Buechel, M.; Nijssen, W.; Coehoorn, R.; Blom, P.W.M.; Leeuw, D.M. de

    2006-01-01

    Recent years have seen tremendous advances in the area of organic-based optoelectronic devices and several applications previously envisioned are now reaching the stage of commercial exploitation.[1] Organic field-effect transistors (OFETs) are among these devices and can be arguably viewed as a pos

  8. Microcrystallization of a Solution-Processable Organic Semiconductor in Capillaries for High-Performance Ambipolar Field-Effect Transistors.

    Science.gov (United States)

    Watanabe, Satoshi; Fujita, Takuma; Ribierre, Jean-Charles; Takaishi, Kazuto; Muto, Tsuyoshi; Adachi, Chihaya; Uchiyama, Masanobu; Aoyama, Tetsuya; Matsumoto, Mutsuyoshi

    2016-07-13

    We report on the use of microcrystallization in capillaries to fabricate patterned crystalline microstructures of the low-bandgap ambipolar quinoidal quaterthiophene derivative (QQT(CN)4) from a chloroform solution. Aligned needle-shaped QQT(CN)4 crystals were formed in thin film microstructures using either open- or closed- capillaries made of polydimethylsiloxane (PDMS). Their charge transport properties were evaluated in a bottom-gate top-contact transistor configuration. Hole and electron mobilities were found to be as high as 0.17 and 0.083 cm(2) V(-1) s(-1), respectively, approaching the values previously obtained in individual QQT(CN)4 single crystal microneedles. It was possible to control the size of the needle crystals and the microline arrays by adjusting the structure of the PDMS mold and the concentration of QQT(CN)4 solution. These results demonstrate that the microcrystallization in capillaries technique can be used to simultaneously pattern organic needle single crystals and control the microcrystallization processes. Such a simple and versatile method should be promising for the future development of high-performance organic electronic devices. PMID:27150559

  9. Flexible ambipolar organic field-effect transistors with reverse-offset-printed silver electrodes for a complementary inverter

    Science.gov (United States)

    Park, Junsu; Kim, Minseok; Yeom, Seung-Won; Ha, Hyeon Jun; Song, Hyenggun; Jhon, Young Min; Kim, Yun-Hi; Ju, Byeong-Kwon

    2016-06-01

    We report ambipolar organic field-effect transistors and complementary inverter circuits with reverse-offset-printed (ROP) Ag electrodes fabricated on a flexible substrate. A diketopyrrolopyrrole-based co-polymer (PDPP-TAT) was used as the semiconductor and poly(methyl methacrylate) was used as the gate insulator. Considerable improvement is observed in the n-channel electrical characteristics by inserting a cesium carbonate (Cs2CO3) as the electron-injection/hole-blocking layer at the interface between the semiconductors and the electrodes. The saturation mobility values are 0.35 cm2 V‑1 s‑1 for the p-channel and 0.027 cm2 V‑1 s‑1 for the n-channel. A complementary inverter is demonstrated based on the ROP process, and it is selectively controlled by the insertion of Cs2CO3 onto the n-channel region via thermal evaporation. Moreover, the devices show stable operation during the mechanical bending test using tensile strains ranging from 0.05% to 0.5%. The results confirm that these devices have great potential for use in flexible and inexpensive integrated circuits over a large area.

  10. o-Carborane functionalized pentacenes: synthesis, molecular packing and ambipolar organic thin-film transistors.

    Science.gov (United States)

    Guo, Jixi; Liu, Danqing; Zhang, Jiahui; Zhang, Jiji; Miao, Qian; Xie, Zuowei

    2015-08-01

    New 6,13-bis[1'-(C≡C)-2'-R-1',2'-C2B10H10]pentacenes (R = H, Me, Et, n-Bu) are synthesized and fully characterized. The results show that the alkyl substituents on the second cage carbon have a significant impact on the molecular packing, and the incorporation of the o-carboranyl moiety into a π conjugated system can lower both LUMO and HOMO energy levels, converting a typical p-type semiconductor into an ambipolar one. PMID:26121634

  11. High-Performance Solution-Deposited Ambipolar Organic Transistors Based on Terrylene Diimides

    DEFF Research Database (Denmark)

    Liu, Chuan; Liu, Zhihong; Lemke, Henrik T.;

    2010-01-01

    The thin film transistor characteristics of a soluble molecular semiconductor, terrylene tetracarboxdiimide (TDI), a homologue of perylene tetracarboxdiimide (PDI), have been investigated. In a bottom-gate device structure with benzocyclobutene gate dielectric, n-type behavior with electron...

  12. Outlook and Emerging Semiconducting Materials for Ambipolar Transistors

    NARCIS (Netherlands)

    Bisri, Satria Zulkarnaen; Piliego, Claudia; Gao, Jia; Loi, Maria Antonietta

    2014-01-01

    Ambipolar or bipolar transistors are transistors in which both holes and electrons are mobile inside the conducting channel. This device allows switching among several states: the hole-dominated on-state, the off-state, and the electron-dominated on-state. In the past year, it has attracted great in

  13. Solid-State Organization and Ambipolar Field-Effect Transistors of Benzothiadiazole-Cyclopentadithiophene Copolymer with Long Branched Alkyl Side Chains

    Directory of Open Access Journals (Sweden)

    Martin Baumgarten

    2013-06-01

    Full Text Available The solid-state organization of a benzothiadiazole-cyclopentadithiophene copolymer with long, branched decyl-tetradecyl side chains (CDT-BTZ-C14,10 is investigated. The C14,10 substituents are sterically demanding and increase the π-stacking distance to 0.40 nm from 0.37 nm for the same polymer with linear hexadecyls (C16. Despite the bulkiness, the C14,10 side chains tend to crystallize, leading to a small chain-to-chain distance between lamellae stacks and to a crystal-like microstructure in the thin film. Interestingly, field-effect transistors based on solution processed layers of CDT-BTZ-C14,10 show ambipolar behavior in contrast to CDT-BTZ-C16 with linear side chains, for which hole transport was previously observed. Due to the increased π-stacking distance, the mobilities are only 6 × 10−4 cm²/Vs for electrons and 6 × 10−5 cm²/Vs for holes, while CDT-BTZ-C16 leads to values up to 5.5 cm²/Vs. The ambipolarity is attributed to a lateral shift between stacked backbones provoked by the bulky C14,10 side chains. This reorganization is supposed to change the transfer integrals between the C16 and C14,10 substituted polymers. This work shows that the electronic behavior in devices of one single conjugated polymer (in this case CDT-BTZ can be controlled by the right choice of the substituents to place the backbones in the desired packing.

  14. Ambipolar organic heterojunction transistors based on F16CuPc/CuPc with a MoO3 buffer layer

    International Nuclear Information System (INIS)

    We fabricated heterojunction organic field-effect transistors (OFETs) using copper phthalocyanine (CuPc) and hexadecafluorophtholocyaninatocopper (F16CuPc) as hole transport layer and electron transport layer, respectively. Compared with F16CuPc based OFETs, the electron field-effect mobility in the heterojunction OFETs increased from 3.1 × 10−3 to 8.7 × 10−3 cm2/(V·s), but the p-type behavior was not observed. To enhanced the hole injection, we modified the source–drain electrodes using the MoO3 buffer layer, and the hole injection can be effectively improved. Eventually, the ambipolar transport characteristics of the CuPc/F16CuPc based OFETs with a MoO3 buffer layer were achieved, and the field-effect mobilities of electron and hole were 2.5 × 10−3 and 3.1 × 10−3 cm2/(V·s), respectively. (paper)

  15. F and CF3 substituted solution processable oligo para-phenylenevinylene for ambipolar and hole-transporting organic field effect transistors

    Science.gov (United States)

    Chini, Mrinmoy Kumar; Das, Chayanika; Chatterjee, Shyambo

    2016-07-01

    We have synthesized benzotrifluoromethyl group substituted para-phenylenevinylene oligomer (denoted as PI) and a cooligomer (denoted as PII) by Gilch polymerization route. The ambipolar field-effect transistor (FET) material PI shows hole and electron mobility 1 × 10-4 cm2 V-1 s-1 and 2 × 10-5 cm2 V-1 s-1 respectively. PII shows only hole mobility as high as 0.05 cm2 V-1 s-1 as p-type material. This work highlights the progress of hole-transporting as well as ambipolar material for para-phenylenevinylene derivatives. The results are enlightened on the basis of presence of electronegative substituents and structural modification of the oligomer backbone.

  16. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Air-stable ambipolar organic field effect transistors with heterojunction of pentacene and N,N' -bis(4-trifluoromethylben-zyl) perylene-3,4,9,10-tetracarboxylic diimide

    Science.gov (United States)

    Li, Jian-Feng; Chang, Wen-Li; Ou, Gu-Ping; Zhang, Fu-Jia

    2009-07-01

    Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized. We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB) as a n-type material in the active layer of the OFETs. The field-effect transistor shows highly air-stable ambipolar characteristics with a field-effect hole mobility of 0.18 cm2/(V.s) and field-effect electron mobility of 0.031 cm2/(V.s). Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days. The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane (OTS) self-assembly monolayer between the SiO2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility. The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.

  17. Ambipolar characteristics of microcrystalline silicon thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Kah-Yoong [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany); Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Gordijn, Aad [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); Stiebig, Helmut [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); Malibu GmbH and Co. KG, 33609 Bielefeld (Germany); Knipp, Dietmar [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany)

    2010-04-15

    Hydrogenated microcrystalline silicon ({mu}c-Si:H) has recently attracted significant attention as a promising candidate for thin-film transistors (TFTs) in large-area electronics due to high electron and hole charge carrier mobilities. We report on top-gate ambipolar TFTs based on {mu}c-Si:H prepared by plasma-enhanced chemical vapor deposition at temperatures below 200 C. Electrons and holes are directly injected into the {mu}c-Si:H channel via chromium drain and source contacts. The TFTs exhibit electron and hole charge carrier mobilities of 30-50 cm{sup 2}/Vs and 10-15 cm{sup 2}/Vs, respectively. In this work, the electrical characteristics of the top-gate ambipolar {mu}c-Si:H TFTs are described by a simple analytical model that takes the ambipolar transport into account. The analytical expressions are used to model the transfer curves, the potential and the net surface charge along the channel of the TFTs. The electrical model provides insights into the electronic transport of ambipolar {mu}c-Si:H TFTs (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Ambipolar transistors based on random networks of WS2 nanotubes

    Science.gov (United States)

    Sugahara, Mitsunari; Kawai, Hideki; Yomogida, Yohei; Maniwa, Yutaka; Okada, Susumu; Yanagi, Kazuhiro

    2016-07-01

    WS2 nanotubes are rolled multiwalled nanotubes made of a layered material, tungsten disulfide. Their fibril structures enable the fabrication of random network films; however, these films are nonconducting, and thus have not been used for electronic applications. Here, we demonstrate that carrier injection into WS2 networks using an electrolyte gating approach could cause these networks to act as semiconducting channels. We clarify the Raman characteristics of WS2 nanotubes under electrolyte gating and confirm the feasibility of the injection of electrons and holes. We reveal ambipolar behaviors of the WS2 nanotube networks in field-effect transistor setups with electrolyte gating.

  19. A Highly Sensitive Diketopyrrolopyrrole-Based Ambipolar Transistor for Selective Detection and Discrimination of Xylene Isomers.

    Science.gov (United States)

    Wang, Bin; Huynh, Tan-Phat; Wu, Weiwei; Hayek, Naseem; Do, Thu Trang; Cancilla, John C; Torrecilla, Jose S; Nahid, Masrur Morshed; Colwell, John M; Gazit, Oz M; Puniredd, Sreenivasa Reddy; McNeill, Christopher R; Sonar, Prashant; Haick, Hossam

    2016-06-01

    An ambipolar poly(diketopyrrolopyrrole-terthiophene)-based field-effect transistor (FET) sensitively detects xylene isomers at low ppm levels with multiple sensing features. Combined with pattern-recognition algorithms, a sole ambipolar FET sensor, rather than arrays of sensors, can discriminate highly similar xylene structural isomers from one another. PMID:26996398

  20. Electrostatically Reversible Polarity of Ambipolar α-MoTe2 Transistors.

    Science.gov (United States)

    Nakaharai, Shu; Yamamoto, Mahito; Ueno, Keiji; Lin, Yen-Fu; Li, Song-Lin; Tsukagoshi, Kazuhito

    2015-06-23

    A doping-free transistor made of ambipolar α-phase molybdenum ditelluride (α-MoTe2) is proposed in which the transistor polarity (p-type and n-type) is electrostatically controlled by dual top gates. The voltage signal in one of the gates determines the transistor polarity, while the other gate modulates the drain current. We demonstrate the transistor operation experimentally, with electrostatically controlled polarity of both p- and n-type in a single transistor. PMID:25988597

  1. Sensors: A Highly Sensitive Diketopyrrolopyrrole-Based Ambipolar Transistor for Selective Detection and Discrimination of Xylene Isomers (Adv. Mater. 21/2016).

    Science.gov (United States)

    Wang, Bin; Huynh, Tan-Phat; Wu, Weiwei; Hayek, Naseem; Do, Thu Trang; Cancilla, John C; Torrecilla, Jose S; Nahid, Masrur Morshed; Colwell, John M; Gazit, Oz M; Puniredd, Sreenivasa Reddy; McNeill, Christopher R; Sonar, Prashant; Haick, Hossam

    2016-06-01

    An ambipolar organic field-effect transistor (OFET) based on poly(diketopyrrolopyrrole-terthiophene) (PDPPHD-T3) is shown by P. Sonar, H. Haick, and co-workers on page 4012 to sensitively detect xylene isomers at low to 40 ppm level in multiple sensing features. Combined with pattern-recognition algorithms, a sole ambipolar FET sensor, rather than arrays of sensors, is able to discriminate highly similar xylene structural isomers from each other. PMID:27246920

  2. Ambipolar MoTe2 transistors and their applications in logic circuits.

    Science.gov (United States)

    Lin, Yen-Fu; Xu, Yong; Wang, Sheng-Tsung; Li, Song-Lin; Yamamoto, Mahito; Aparecido-Ferreira, Alex; Li, Wenwu; Sun, Huabin; Nakaharai, Shu; Jian, Wen-Bin; Ueno, Keiji; Tsukagoshi, Kazuhito

    2014-05-28

    We report ambipolar charge transport in α-molybdenum ditelluride (MoTe2 ) flakes, whereby the temperature dependence of the electrical characteristics was systematically analyzed. The ambipolarity of the charge transport originated from the formation of Schottky barriers at the metal/MoTe2 contacts. The Schottky barrier heights as well as the current on/off ratio could be modified by modulating the electrostatic fields of the back-gate voltage (Vbg) and drain-source voltage (Vds). Using these ambipolar MoTe2 transistors we fabricated complementary inverters and amplifiers, demonstrating their feasibility for future digital and analog circuit applications. PMID:24692079

  3. Control of Threshold Voltage for Top-Gated Ambipolar Field-Effect Transistor by Gate Buffer Layer.

    Science.gov (United States)

    Khim, Dongyoon; Shin, Eul-Yong; Xu, Yong; Park, Won-Tae; Jin, Sung-Ho; Noh, Yong-Young

    2016-07-13

    The threshold voltage and onset voltage for p-channel and n-channel regimes of solution-processed ambipolar organic transistors with top-gate/bottom-contact (TG/BC) geometry were effectively tuned by gate buffer layers in between the gate electrode and the dielectric. The work function of a pristine Al gate electrode (-4.1 eV) was modified by cesium carbonate and vanadium oxide to -2.1 and -5.1 eV, respectively, which could control the flat-band voltage, leading to a remarkable shift of transfer curves in both negative and positive gate voltage directions without any side effects. One important feature is that the mobility of transistors is not very sensitive to the gate buffer layer. This method is simple but useful for electronic devices where the threshold voltage should be precisely controlled, such as ambipolar circuits, memory devices, and light-emitting device applications. PMID:27323003

  4. Enhancement of minority carrier injection in ambipolar carbon nanotube transistors using double-gate structures

    Science.gov (United States)

    Kim, Bongjun; Liang, Kelly; Geier, Michael L.; Hersam, Mark C.; Dodabalapur, Ananth

    2016-07-01

    We show that double-gate ambipolar thin-film transistors can be operated to enhance minority carrier injection. The two gate potentials need to be significantly different for enhanced injection to be observed. This enhancement is highly beneficial in devices such as light-emitting transistors where balanced electron and hole injections lead to optimal performance. With ambipolar single-walled carbon nanotube semiconductors, we demonstrate that higher ambipolar currents are attained at lower source-drain voltages, which is desired for portable electronic applications, by employing double-gate structures. In addition, when the two gates are held at the same potential, the expected advantages of the double-gate transistors such as enhanced on-current are also observed.

  5. Ambipolar Cu- and Fe-phthalocyanine single-crystal field-effect transistors

    NARCIS (Netherlands)

    De Boer, R.W.I.; Stassen, A.F.; Craciun, M.F.; Mulder, C.L.; Molinari, A.; Rogge, S.; Morpurgo, A.F.

    2005-01-01

    We report the observation of ambipolar transport in field-effect transistors fabricated on single crystals of copper- and iron-phthalocyanine, using gold as a high work-function metal for the fabrication of source and drain electrodes. In these devices, the room-temperature mobility of holes reaches

  6. Ambipolar field-effect transistor of high photoluminescent material tetraphenylpyrene (TPPy) single crystal

    NARCIS (Netherlands)

    Bisri, Satria Zulkarnaen; Takahashi, Tetsuo; Takenobu, Taishi; Yahir, Masayuki; Adachi, Chihaya; Iwasa, Yoshihiro

    2007-01-01

    An ambipolar field-effect transistor (FET) based on a 1,3,6,8-tetraphenylpyrene (TPPy) single crystal, a highly photoluminescent material, has been successfully fabricated. Several kinds of metal electrodes have been employed to investigate the charge injection characteristics into the single-crysta

  7. Ambipolar Tetraphenylpyrene (TPPy) Single-Crystal Field-Effect Transistor with Symmetric and Asymmetric Electrodes

    NARCIS (Netherlands)

    Bisri, S Z; Takahashi, T; Takenobu, T; Yahiro, M; Adachi, C; Iwasa, Y

    2008-01-01

    An ambipolar field-effect transistor (FET) based on a 1,3,6, 8-tetraphenylpyrene (TPPy) single-crystal, a high photoluminescent material, has been successfully fabricated using symmetric and asymmetric electrodes. Several kinds of metal electrodes have been employed to investigate the charge injecti

  8. Ambipolar MoS2 Thin Flake Transistors

    NARCIS (Netherlands)

    Zhang, Yijin; Ye, Jianting; Matsuhashi, Yusuke; Iwasa, Yoshihiro

    2012-01-01

    Field effect transistors (FETs) made of thin flake single crystals isolated from layered materials have attracted growing interest since the success of graphene. Here, we report the fabrication of an electric double layer transistor (EDLT, a FET gated by ionic liquids) using a thin flake of MoS2, a

  9. Ambipolar all-polymer bulk heterojunction field-effect transistors

    NARCIS (Netherlands)

    Szendrei, Krisztina; Jarzab, Dorota; Chen, Zhihua; Facchetti, Antonio; Loi, Maria A.

    2010-01-01

    We demonstrate solution processable all-polymer based field-effect transistors (FETs) exhibiting comparable electron and hole mobilities. The semiconducting layer is a bulk heterojunction of poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)}

  10. Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth, E-mail: ananth.dodabalapur@engr.utexas.edu [Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States); Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Geier, Michael L.; Prabhumirashi, Pradyumna L. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Hersam, Mark C. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Department of Medicine, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-02-10

    We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm{sup 2} V{sup −1} s{sup −1} at low operating voltages (<5 V) in air. We further show that the SWCNT-ZTO hybrid ambipolar FETs can be integrated into functional inverter circuits that display high peak gain (>10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures.

  11. Memory operation devices based on light-illumination ambipolar carbon-nanotube thin-film-transistors

    Energy Technology Data Exchange (ETDEWEB)

    Aïssa, B., E-mail: aissab@emt.inrs.ca [Qatar Environment and Energy Research Institute (QEERI), Qatar Foundation, P.O. Box 5825, Doha (Qatar); Centre Energie, Matériaux et Télécommunications, INRS, 1650, Boulevard Lionel-Boulet Varennes, Quebec J3X 1S2 (Canada); Nedil, M. [Telebec Wireless Underground Communication Laboratory, UQAT, 675, 1ère Avenue, Val d' Or, Quebec J9P 1Y3 (Canada); Kroeger, J. [NanoIntegris & Raymor Nanotech, Raymor Industries Inc., 3765 La Vérendrye, Boisbriand, Quebec J7H 1R8 (Canada); Haddad, T. [Department of Mechanical Engineering, McGill University, Montreal, Quebec H3A 0B8 (Canada); Rosei, F. [Centre Energie, Matériaux et Télécommunications, INRS, 1650, Boulevard Lionel-Boulet Varennes, Quebec J3X 1S2 (Canada)

    2015-09-28

    We report the memory operation behavior of a light illumination ambipolar single-walled carbon nanotube thin film field-effect transistors devices. In addition to the high electronic-performance, such an on/off transistor-switching ratio of 10{sup 4} and an on-conductance of 18 μS, these memory devices have shown a high retention time of both hole and electron-trapping modes, reaching 2.8 × 10{sup 4} s at room temperature. The memory characteristics confirm that light illumination and electrical field can act as an independent programming/erasing operation method. This could be a fundamental step toward achieving high performance and stable operating nanoelectronic memory devices.

  12. Ambipolar nonvolatile memory based on a quantum-dot transistor with a nanoscale floating gate

    Science.gov (United States)

    Che, Yongli; Zhang, Yating; Cao, Xiaolong; Song, Xiaoxian; Cao, Mingxuan; Dai, Haitao; Yang, Junbo; Zhang, Guizhong; Yao, Jianquan

    2016-07-01

    Using only solution processing methods, we developed ambipolar quantum-dot (QD) transistor floating-gate memory (FGM) that uses Au nanoparticles as a floating gate. Because of the bipolarity of the active channel of PbSe QDs, the memory could easily trap holes or electrons in the floating gate by programming/erasing (P/E) operations, which could shift the threshold voltage both up and down. As a result, the memory exhibited good programmable memory characteristics: a large memory window (ΔVth ˜ 15 V) and a long retention time (>105 s). The magnitude of ΔVth depended on both P/E voltages and the bias voltage (VDS): ΔVth was a cubic function to VP/E and linearly depended on VDS. Therefore, this FGM based on a QD transistor is a promising alternative to its inorganic counterparts owing to its advantages of bipolarity, high mobility, low cost, and large-area production.

  13. Memory operation devices based on light-illumination ambipolar carbon-nanotube thin-film-transistors

    International Nuclear Information System (INIS)

    We report the memory operation behavior of a light illumination ambipolar single-walled carbon nanotube thin film field-effect transistors devices. In addition to the high electronic-performance, such an on/off transistor-switching ratio of 104 and an on-conductance of 18 μS, these memory devices have shown a high retention time of both hole and electron-trapping modes, reaching 2.8 × 104 s at room temperature. The memory characteristics confirm that light illumination and electrical field can act as an independent programming/erasing operation method. This could be a fundamental step toward achieving high performance and stable operating nanoelectronic memory devices

  14. Utilizing carbon nanotube electrodes to improve charge injection and transport in bis(trifluoromethyl)-dimethyl-rubrene ambipolar single crystal transistors.

    Science.gov (United States)

    Xie, Wei; Prabhumirashi, Pradyumna L; Nakayama, Yasuo; McGarry, Kathryn A; Geier, Michael L; Uragami, Yuki; Mase, Kazuhiko; Douglas, Christopher J; Ishii, Hisao; Hersam, Mark C; Frisbie, C Daniel

    2013-11-26

    We have examined the significant enhancement of ambipolar charge injection and transport properties of bottom-contact single crystal field-effect transistors (SC-FETs) based on a new rubrene derivative, bis(trifluoromethyl)-dimethyl-rubrene (fm-rubrene), by employing carbon nanotube (CNT) electrodes. The fundamental challenge associated with fm-rubrene crystals is their deep-lying HOMO and LUMO energy levels, resulting in inefficient hole injection and suboptimal electron injection from conventional Au electrodes due to large Schottky barriers. Applying thin layers of CNT network at the charge injection interface of fm-rubrene crystals substantially reduces the contact resistance for both holes and electrons; consequently, benchmark ambipolar mobilities have been achieved, reaching 4.8 cm(2) V(-1) s(-1) for hole transport and 4.2 cm(2) V(-1) s(-1) for electron transport. We find that such improved injection efficiency in fm-rubrene is beneficial for ultimately unveiling its intrinsic charge transport properties so as to exceed those of its parent molecule, rubrene, in the current device architecture. Our studies suggest that CNT electrodes may provide a universal approach to ameliorate the charge injection obstacles in organic electronic devices regardless of charge carrier type, likely due to the electric field enhancement along the nanotube located at the crystal/electrode interface. PMID:24175573

  15. Leveraging the ambipolar transport in polymeric field-effect transistors via blending with liquid-phase exfoliated graphene.

    Science.gov (United States)

    El Gemayel, Mirella; Haar, Sébastien; Liscio, Fabiola; Schlierf, Andrea; Melinte, Georgian; Milita, Silvia; Ersen, Ovidiu; Ciesielski, Artur; Palermo, Vincenzo; Samorì, Paolo

    2014-07-23

    Enhancement in the ambipolar behavior of field-effect transistors based on an n-type polymer, P(NDI2OD-T2), is obtained by co-deposition with liquid-phase exfoliated graphene. This approach provides a prospective pathway for the application of graphene-based nanocomposites for logic circuits.

  16. Formation of a Stable p-n Junction in a Liquid-Gated MoS2 Ambipolar Transistor

    NARCIS (Netherlands)

    Zhang, Y. J.; Ye, J. T.; Yornogida, Y.; Takenobu, T.; Iwasa, Y.

    2013-01-01

    Molybdenum disulfide (MoS2) has gained attention because of its high mobility and circular dichroism. As a crucial step to merge these advantages into a single device, we present a method that electronically controls and locates p-n junctions in liquid-gated ambipolar MoS2 transistors. A bias-indepe

  17. Recent progress in photoactive organic field-effect transistors

    International Nuclear Information System (INIS)

    Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These are categorized according to their functionalities: phototransistors, non-volatile optical memories, and photochromism-based transistors. For both, various device configurations are introduced: thin-film based transistors for practical applications, single-crystalline transistors to investigate fundamental physics, nanowires, multi-layers, and vertical transistors based on new concepts. (review)

  18. Vertical organic transistors

    International Nuclear Information System (INIS)

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted. (topical review)

  19. Recent progress in photoactive organic field-effect transistors

    OpenAIRE

    Yutaka Wakayama; Ryoma Hayakawa; Hoon-Seok Seo

    2014-01-01

    Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These ar...

  20. Single-charge transport in ambipolar silicon nanoscale field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Filipp; Konstantaras, Georgios; Wiel, Wilfred G. van der; Zwanenburg, Floris A., E-mail: f.a.zwanenburg@utwente.nl [NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2015-04-27

    We report single-charge transport in ambipolar nanoscale MOSFETs, electrostatically defined in near-intrinsic silicon. We use the ambipolarity to demonstrate the confinement of either a few electrons or a few holes in exactly the same crystalline environment underneath a gate electrode. We find similar electron and hole quantum dot properties while the mobilities differ quantitatively like in microscale devices. The understanding and control of individual electrons and holes are essential for spin-based quantum information processing.

  1. Multi-color light-emitting transistors composed of organic single crystals

    NARCIS (Netherlands)

    Yomogida, Yohei; Sakai, Hayato; Sawabe, Kosuke; Gocho, Shota; Bisri, Satria Zulkarnaen; Nakanotani, Hajime; Adachi, Chihaya; Hasobe, Taku; Iwasa, Yoshihiro; Takenobu, Taishi

    2013-01-01

    We report a novel concept for multi-color light emission from an ambipolar organic single-crystal transistor using natural optical waveguides, the self-absorption effect, Davydov splitting and the unique alignment of the transition dipole moments. We used 9,10-bis(2,2-diphenylvinyl)-anthracene singl

  2. Organic Light-Emitting Transistors

    OpenAIRE

    Karg, Siegfried; Rost-Bietsch, Constance; Riess, Walter; Loi, Maria Antonietta; Murgia, Mauro; Muccini, Michele

    2005-01-01

    A light-emitting OFET with pronounced ambipolar current characteristic has been prepared by co-evaporation of α-quinquethiophene (α-5T) as hole-transport material and ditridecyl-perylene-tetracarboxylic diimide (P13) as electron-transport material. The light intensity is controlled by both the drain-source voltage VDS and the gate voltage VG. Here, we demonstrate the general concept of adjusting electron and hole mobilities by co-evaporation of two different organic semiconductors.

  3. Ambipolar charge carrier transport in organic semiconductor blends of C{sub 60} and CuPc; Ambipolarer Ladungstransport in organischen Halbleiter-Mischschichten bestehend aus C{sub 60} und CuPc

    Energy Technology Data Exchange (ETDEWEB)

    Bronner, Markus

    2008-06-20

    In this work ambipolar charge carrier transport is realised in organic field effect transistors using mixtures of p-conductive copper phthalocyanine and n-conductive buckminster fullerene as active layer. These blends are known from research on organic solar cells and can be considered as a model system for ambipolar transport. The field effect mobilities for electrons and holes can be adjusted by the variation of the mixing ratio. Thereby balanced mobilities for both charge carrier types are possible. In this work the variation of mobility, threshold voltage and electronic energy levels with the mixing ratio is discussed. The charge carrier mobilities are strongly reduced upon dilution of the respective conducting phase by the other species. This shows that transport of each carrier species occurs by percolation through the respective phase in the blend. A strong correlation between contact resistance and mobility indicates that carrier injection is diffusion limited. A charge redistribution in the copper phthalocyanine causes a hole accumulation at the organic/organic interface and affects thereby the threshold voltage for holes. The electronic structure was investigated by photoelectron spectroscopy. It was found that there is no chemical reaction between the different materials. The common work function of these blends changes linearly between the work functions of the neat materials. Moreover, a constant ionisation potential for the highest occupied molecular orbitals of the two materials and the core levels is obtained. Furthermore ambipolar inverters using mixed organic semiconductor layers were made and compared to complementary inverters consisting of discrete p- and n-channel transistors. The experimental findings and concomitant simulations demonstrate the need for balanced electron and hole mobilities in order to achieve symmetric inverter characteristics. However, they also reveal the superior performance of true complementary logic inverters towards

  4. High-performance ambipolar self-assembled Au/Ag nanowire based vertical quantum dot field effect transistor.

    Science.gov (United States)

    Song, Xiaoxian; Zhang, Yating; Zhang, Haiting; Yu, Yu; Cao, Mingxuan; Che, Yongli; Wang, Jianlong; Dai, Haitao; Yang, Junbo; Ding, Xin; Yao, Jianquan

    2016-10-01

    Most lateral PbSe quantum dot field effect transistors (QD FETs) show a low on current/off current (I on/I off) ratio in charge transport measurements. A new strategy to provide generally better performance is to design PbSe QD FETs with vertical architecture, in which the structure parameters can be tuned flexibly. Here, we fabricated a novel room-temperature operated vertical quantum dot field effect transistor with a channel of 580 nm, where self-assembled Au/Ag nanowires served as source transparent electrodes and PbSe quantum dots as active channels. Through investigating the electrical characterization, the ambipolar device exhibited excellent characteristics with a high I on/I off current ratio of about 1 × 10(5) and a low sub-threshold slope (0.26 V/decade) in the p-type regime. The all-solution processing vertical architecture provides a convenient way for low cost, large-area integration of the device. PMID:27578613

  5. Field-Effect Transistors Based on Few-Layered Ambipolar MoSe2 and α-MoTe2

    Science.gov (United States)

    Rhodes, Daniel; Pradhan, Nihar; Feng, Simin; Moon, Byoung-Hee; Xin, Yan; Memaran, Sharhriar; Siddiq, Muhandis; Bhaskaran, Lakshmi; Hill, Stephen; Terrones, Humberto; Terrones, Mauricio; Pulickel, Ajayan; Balicas, Luis

    2015-03-01

    We report a room temperature study on the electrical responses of field-effect transistors (FETs) based on few-layered MoSe2 and MoTe2, grown by chemical vapor transport, mechanically exfoliated onto SiO2. MoSe2 FETs electrically contacted with Ti display ambipolar behavior with current on/off ratios up to 106 for both hole and electron channels. For both channels the Hall effect indicates Hall mobilities μH ~= 250 cm2/(Vs), which are comparable to the corresponding field-effect mobilities, μFE ~ 175 cm2/(Vs), evaluated through two-terminal field-effect configuration. MoTe2 field-effect transistors are observed to be hole-doped, displaying on/off ratios of ~ 106 and subthreshold swings of ~140 mV per decade. Our results suggest that MoSe2 is a good candidate for single atomic layer p -n junctions and for low-power, complementary logic applications, with MoTe2 having similar properties. However, in MoTe2 we observe a field-effect mobility of only μFE ~ 20 cm2/(Vs) in a bilayer device and ~ 27 cm2/(Vs) in seven layers. This work was supported by the U.S. Army Research Office MURI Grant No. W911NF-11-1-0362. The NHMFL is supported by NSF through NSF-DMR-0084173 and the State of Florida.

  6. High-performance ambipolar self-assembled Au/Ag nanowire based vertical quantum dot field effect transistor

    Science.gov (United States)

    Song, Xiaoxian; Zhang, Yating; Zhang, Haiting; Yu, Yu; Cao, Mingxuan; Che, Yongli; Wang, Jianlong; Dai, Haitao; Yang, Junbo; Ding, Xin; Yao, Jianquan

    2016-10-01

    Most lateral PbSe quantum dot field effect transistors (QD FETs) show a low on current/off current (I on/I off) ratio in charge transport measurements. A new strategy to provide generally better performance is to design PbSe QD FETs with vertical architecture, in which the structure parameters can be tuned flexibly. Here, we fabricated a novel room-temperature operated vertical quantum dot field effect transistor with a channel of 580 nm, where self-assembled Au/Ag nanowires served as source transparent electrodes and PbSe quantum dots as active channels. Through investigating the electrical characterization, the ambipolar device exhibited excellent characteristics with a high I on/I off current ratio of about 1 × 105 and a low sub-threshold slope (0.26 V/decade) in the p-type regime. The all-solution processing vertical architecture provides a convenient way for low cost, large-area integration of the device.

  7. Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

    International Nuclear Information System (INIS)

    Ambipolar semiconducting polymers, characterized by both high electron (μe) and hole (μh) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μh = 0.29 cm2/V s and μe = 0.001 cm2/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μe = 0.12 cm2/V s and μh = 8 × 10−4 cm2/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic

  8. Tetracene dicarboxylic imide and its disulfide: synthesis of ambipolar organic semiconductors for organic photovoltaic cells.

    Science.gov (United States)

    Okamoto, Toshihiro; Suzuki, Tsuyoshi; Tanaka, Hideyuki; Hashizume, Daisuke; Matsuo, Yutaka

    2012-01-01

    We have designed and synthesized a new donor/acceptor-type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron-withdrawing and -donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long-wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face-to-face π-stacking, derived from dipole-dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron-donating and -accepting natures in p-n and p-i-n heterojunction organic thin-film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors.

  9. Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

    Energy Technology Data Exchange (ETDEWEB)

    Dell' Erba, Giorgio; Natali, Dario [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Luzio, Alessandro; Caironi, Mario, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Kim, Juhwan; Khim, Dongyoon; Kim, Dong-Yu [Heeger Center for Advanced Materials, School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Noh, Yong-Young, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Department of Energy and Materials Engineering, Dongguk University, 26 Pil-dong, 3-ga, Jung-gu, Seoul 100-715 (Korea, Republic of)

    2014-04-14

    Ambipolar semiconducting polymers, characterized by both high electron (μ{sub e}) and hole (μ{sub h}) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μ{sub h} = 0.29 cm{sup 2}/V s and μ{sub e} = 0.001 cm{sup 2}/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μ{sub e} = 0.12 cm{sup 2}/V s and μ{sub h} = 8 × 10{sup −4} cm{sup 2}/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic.

  10. N-type organic electrochemical transistors with stability in water

    Science.gov (United States)

    Giovannitti, Alexander; Nielsen, Christian B.; Sbircea, Dan-Tiberiu; Inal, Sahika; Donahue, Mary; Niazi, Muhammad R.; Hanifi, David A.; Amassian, Aram; Malliaras, George G.; Rivnay, Jonathan; McCulloch, Iain

    2016-10-01

    Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen. This new semiconducting polymer is designed specifically to facilitate ion transport and promote electrochemical doping. Stability measurements in water show no degradation when tested for 2 h under continuous cycling. This demonstration opens the possibility to develop complementary circuits based on OECTs and to improve the sophistication of bioelectronic devices.

  11. N-type organic electrochemical transistors with stability in water

    Science.gov (United States)

    Giovannitti, Alexander; Nielsen, Christian B.; Sbircea, Dan-Tiberiu; Inal, Sahika; Donahue, Mary; Niazi, Muhammad R.; Hanifi, David A.; Amassian, Aram; Malliaras, George G.; Rivnay, Jonathan; McCulloch, Iain

    2016-01-01

    Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen. This new semiconducting polymer is designed specifically to facilitate ion transport and promote electrochemical doping. Stability measurements in water show no degradation when tested for 2 h under continuous cycling. This demonstration opens the possibility to develop complementary circuits based on OECTs and to improve the sophistication of bioelectronic devices. PMID:27713414

  12. N-type organic electrochemical transistors with stability in water

    KAUST Repository

    Giovannitti, Alexander

    2016-10-07

    Organic electrochemical transistors (OECTs) are receiving significant attention due to their ability to efficiently transduce biological signals. A major limitation of this technology is that only p-type materials have been reported, which precludes the development of complementary circuits, and limits sensor technologies. Here, we report the first ever n-type OECT, with relatively balanced ambipolar charge transport characteristics based on a polymer that supports both hole and electron transport along its backbone when doped through an aqueous electrolyte and in the presence of oxygen. This new semiconducting polymer is designed specifically to facilitate ion transport and promote electrochemical doping. Stability measurements in water show no degradation when tested for 2 h under continuous cycling. This demonstration opens the possibility to develop complementary circuits based on OECTs and to improve the sophistication of bioelectronic devices.

  13. Interface engineering in organic transistors

    Directory of Open Access Journals (Sweden)

    Yeong Don Park

    2007-03-01

    Full Text Available Recent technological advances in organic field-effect transistors (OFETs have triggered intensive research into the molecular and mesoscale structures of organic semiconductor films that determine their charge-transport characteristics. Since the molecular structure and morphology of an organic semiconductor are largely determined by the properties of the interface between the organic film and the insulator, a great deal of research has focused on interface engineering. We review recent progress in interface engineering for the fabrication of high-performance OFETs and, in particular, engineering of the interfaces between semiconductors and insulators. The effects of interfacial characteristics on the molecular and mesoscale structures of π-conjugated molecules and the performance of OFET devices are discussed.

  14. Organic and polymer transistors for electronics

    Directory of Open Access Journals (Sweden)

    Ananth Dodabalapur

    2006-04-01

    Full Text Available Some of the major application areas for organic and polymeric transistors are reviewed. Organic complementary devices are promising on account of their lower power dissipation and ease of circuit design. The first organic large-scale integrated circuits have been implemented with this circuit approach. Organic transistor backplanes are ideally suited for electronic paper applications and other display schemes. Low-cost and other processing advantages, as well as improving performance, have led to organic-based radio frequency identification tag development. The chemical interaction between various organic and polymer semiconductors can be exploited in chemical and biological sensors based upon organic transistors.

  15. Equivalent ambipolar carrier injection of electrons and holes with Au electrodes in air-stable field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kanagasekaran, Thangavel, E-mail: kanagasekaran@gmail.com, E-mail: Shimotani@m.tohoku.ac.jp, E-mail: tanigaki@m.tohoku.ac.jp; Ikeda, Susumu; Kumashiro, Ryotaro [WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Shimotani, Hidekazu, E-mail: kanagasekaran@gmail.com, E-mail: Shimotani@m.tohoku.ac.jp, E-mail: tanigaki@m.tohoku.ac.jp; Shang, Hui [Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba, Sendai 980-8578 (Japan); Tanigaki, Katsumi, E-mail: kanagasekaran@gmail.com, E-mail: Shimotani@m.tohoku.ac.jp, E-mail: tanigaki@m.tohoku.ac.jp [WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577 (Japan); Department of Physics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba, Sendai 980-8578 (Japan)

    2015-07-27

    Carrier injection from Au electrodes to organic thin-film active layers can be greatly improved for both electrons and holes by nano-structural surface control of organic semiconducting thin films using long-chain aliphatic molecules on a SiO{sub 2} gate insulator. In this paper, we demonstrate a stark contrast for a 2,5-bis(4-biphenylyl)bithiophene (BP2T) active semiconducting layer grown on a modified SiO{sub 2} dielectric gate insulator between two different modifications of tetratetracontane and poly(methyl methacrylate) thin films. Important evidence that the field effect transistor (FET) characteristics are independent of electrode metals with different work functions is given by the observation of a conversion of the metal-semiconductor contact from the Schottky limit to the Bardeen limit. An air-stable light emitting FET with an Au electrode is demonstrated.

  16. Organic semiconductors for organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yoshiro Yamashita

    2009-01-01

    Full Text Available The advantages of organic field-effect transistors (OFETs, such as low cost, flexibility and large-area fabrication, have recently attracted much attention due to their electronic applications. Practical transistors require high mobility, large on/off ratio, low threshold voltage and high stability. Development of new organic semiconductors is key to achieving these parameters. Recently, organic semiconductors have been synthesized showing comparable mobilities to amorphous-silicon-based FETs. These materials make OFETs more attractive and their applications have been attempted. New organic semiconductors resulting in high-performance FET devices are described here and the relationship between transistor characteristics and chemical structure is discussed.

  17. Advancement in organic nanofiber based transistors

    DEFF Research Database (Denmark)

    Jensen, Per Baunegaard With; Kjelstrup-Hansen, Jakob; Tavares, Luciana;

    The focus of this project is to study the light emission from nanofiber based organic light-emitting transistors (OLETs) with the overall aim of developing efficient, nanoscale light sources with different colors integrated on-chip. The research performed here regards the fabrication and characte......The focus of this project is to study the light emission from nanofiber based organic light-emitting transistors (OLETs) with the overall aim of developing efficient, nanoscale light sources with different colors integrated on-chip. The research performed here regards the fabrication...

  18. Effects of germane flow rate in electrical properties of a-SiGe:H films for ambipolar thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, Miguel, E-mail: madominguezj@gmail.com [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Rosales, Pedro, E-mail: prosales@inaoep.mx [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Torres, Alfonso [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Flores, Francisco [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Molina, Joel; Moreno, Mario [National Institute for Astrophysics, Optics and Electronics (INAOE), Electronics Department, Luis Enrique Erro No. 1, Puebla 72840 (Mexico); Luna, Jose [Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla (BUAP), Puebla 72570 (Mexico); Orduña, Abdu [Centro de Investigación en Biotecnología Aplicada (CIBA), IPN, Tlaxcala, Tlaxcala 72197 (Mexico)

    2014-07-01

    In this work, the study of germane flow rate in electrical properties of a-SiGe:H films is presented. The a-SiGe:H films deposited by low frequency plasma-enhanced chemical vapor deposition at 300 °C were characterized by Fourier transform infrared spectroscopy, measurements of temperature dependence of conductivity and UV–visible spectroscopic ellipsometry. After finding the optimum germane flow rate conditions, a-SiGe:H films were deposited at 200 °C and analyzed. The use of a-SiGe:H films at 200 °C as active layer of low-temperature ambipolar thin-film transistors (TFTs) was demonstrated. The inverted staggered a-SiGe:H TFTs with Spin-On Glass as gate insulator were fabricated. These results suggest that there is an optimal Ge content in the a-SiGe:H films that improves its electrical properties. - Highlights: • As the GeH{sub 4} flow rate increases the content of oxygen decreases. • Ge-H bonds show the highest value in a-SiGe:H films with GeH{sub 4} flow of 105 sccm. • Films with GeH{sub 4} flow of 105 sccm show the highest activation energy. • An optimum incorporation of germanium is obtained with GeH{sub 4} flow rate of 105 sccm. • At 200 °C the optimum condition of the a-SiGe:H films remain with no changes.

  19. Transistors

    CERN Document Server

    Kendall, E J M

    2013-01-01

    Transistors covers the main thread of transistor development. This book is organized into 2 parts encompassing 19, and starts with an overview of the semi-conductor physics pertinent to the understanding of transistors, as well as features and applications of the point contact devices and junction devices. The subsequent part deals with the modulation of conductance of thin films of conductors by surface charges, the metal-semi conductor, and the semi-conductor triode. These topics are followed by discussions on the nature of the forward current, physical principles in transistor, the hole inj

  20. Electrical Characteristics of Copper Phthalocyanine Thin-Film Transistors with Polyamide-6/Polytetrafluoroethylene Gate Insulator

    Institute of Scientific and Technical Information of China (English)

    YU Shun-Yang; XU Shi-Ai; MA Dong-Ge

    2007-01-01

    Polyamide-6(PA 6)/polytetrafluoroethylene is studied as a potential gate dielectric for flexible organic thin film transistors.The salne method used for the formation of organic semiconductor and gate dielectric films greatly simplifies the fabrication process of devices.The fabricated transistors show good electrical characteristics.Ambipolar behaviour is observed even when the device is operated in air.

  1. Organic Thin-Film Transistor (OTFT-Based Sensors

    Directory of Open Access Journals (Sweden)

    Daniel Elkington

    2014-04-01

    Full Text Available Organic thin film transistors have been a popular research topic in recent decades and have found applications from flexible displays to disposable sensors. In this review, we present an overview of some notable articles reporting sensing applications for organic transistors with a focus on the most recent publications. In particular, we concentrate on three main types of organic transistor-based sensors: biosensors, pressure sensors and “e-nose”/vapour sensors.

  2. Organic Thin-Film Transistor (OTFT)-Based Sensors

    OpenAIRE

    Daniel Elkington; Nathan Cooling; Warwick Belcher; Paul C. Dastoor; Xiaojing Zhou

    2014-01-01

    Organic thin film transistors have been a popular research topic in recent decades and have found applications from flexible displays to disposable sensors. In this review, we present an overview of some notable articles reporting sensing applications for organic transistors with a focus on the most recent publications. In particular, we concentrate on three main types of organic transistor-based sensors: biosensors, pressure sensors and “e-nose”/vapour sensors.

  3. Organic transistors for electrophysiology (Presentation Recording)

    Science.gov (United States)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  4. Properties of polymer light-emitting transistors with Ag-nanowire source/drain electrodes fabricated on polymer substrate

    International Nuclear Information System (INIS)

    The properties of polymer light-emitting transistors with Ag-nanowire (AgNW) source/drain electrodes fabricated on a polymer substrate are investigated. Organic field-effect transistors (OFETs) based on poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) with AgNW source/drain electrodes exhibit ambipolar characteristics. For an ambipolar F8BT OFET, yellow-green light emission is observed. The maximum external quantum efficiency is 0.6%. We demonstrate the possibility of producing flexible polymer light-emitting transistors using AgNW electrodes. - Highlights: • Fluorene-type organic field-effect transistors (OFETs) are investigated. • We use Ag-nanowire (AgNW) source/drain electrodes in the OFETs. • These OFETs exhibit ambipolar and light-emitting characteristics. • The maximum external quantum efficiency is 0.6%. • We demonstrate flexible polymer light-emitting transistors using AgNW electrodes

  5. Fabrication and characterization of advanced Organic Thin Film Transistors

    OpenAIRE

    Scaldaferri, Rossana

    2009-01-01

    The thesis aims to the development of Organic Thin Film Transistors and more complex devices based on organic materials. The experimental work demonstrates the possibility to manufacture transistors and more complex circuits with innovative polymers and technologies, leading to an experimental validation of the possibility to realize all-organic devices.

  6. Printed shadow masks for organic transistors

    Science.gov (United States)

    Noguchi, Yoshiaki; Sekitani, Tsuyoshi; Someya, Takao

    2007-09-01

    We have manufactured organic field-effect transistors by using shadow masks that are patterned by a screen printing system. The 50-nm-thick pentacene layer is sublimed as a channel in the vacuum system through the shadow mask on the base film with a multilayer patterned by ink-jet. After the deposition of the pentacene layer, the shadow mask is peeled off from the base film without any mechanical damages to the lower structures. The mobility in the saturation regime is 0.4cm2/Vs and the on-off ratio exceeds 105.

  7. Low voltage and time constant organic synapse-transistor

    OpenAIRE

    Desbief, Simon; Kyndiah, Adrica; Guerin, David; Gentili, Denis; Murgia, Mauro; Lenfant, Stéphane; Alibart, Fabien; Cramer, Tobias; Biscarini, Fabio; Vuillaume, Dominique

    2015-01-01

    We report on an artificial synapse, an organic synapse-transistor (synapstor) working at 1 volt and with a typical response time in the range 100-200 ms. This device (also called NOMFET, Nanoparticle Organic Memory Field Effect Transistor) combines a memory and a transistor effect in a single device. We demonstrate that short-term plasticity (STP), a typical synaptic behavior, is observed when stimulating the device with input spikes of 1 volt. Both significant facilitating and depressing beh...

  8. High Performance Ambipolar Diketopyrrolopyrrole-Thieno[3,2-b]thiophene Copolymer Field-Effect Transistors with Balanced Hole and Electron Mobilities

    DEFF Research Database (Denmark)

    Chen, Zhuoying; Lee, Mi Jung; Ashraf, Raja Shahid;

    2012-01-01

    Ambipolar OFETs with balanced hole and electron field-effect mobilities both exceeding 1 cm2 V−1 s−1 are achieved based on a single-solution-processed conjugated polymer, DPPT-TT, upon careful optimization of the device architecture, charge injection, and polymer processing. Such high-performance...

  9. Organic Light-Emitting Diodes Driven by Organic Transistors

    Institute of Scientific and Technical Information of China (English)

    胡远川; 董桂芳; 王立铎; 梁琰; 邱勇

    2004-01-01

    Organic thin-film field-effect transistors (OTFTs) with pentacene as the semiconductor have been fabricated for driving an organic light-emitting diode (OLED). The driving circuit includes two OTFTs and one storage capacitor. The field-effect mobility of the transistors in the driving circuit is more than 0.3 cm2/Vs, and the on/off ratio is larger than 104. The light-emission area of the OLED is 0. 04mm2 and the brightness is larger than 400cd/m2 when the selected line voltage, data line voltage and drive voltage all are -40 V. The responding characteristics and holding characteristics are also researched when the selected line voltage and the date line voltage are changed.

  10. Progresses in organic field-effect transistors and molecular electronics

    Institute of Scientific and Technical Information of China (English)

    Wu Weiping; Xu Wei; Hu Wenping; Liu Yunqi; Zhu Daoben

    2006-01-01

    In the past years,organic semiconductors have been extensively investigated as electronic materials for organic field-effect transistors (OFETs).In this review,we briefly summarize the current status of organic field-effect transistors including materials design,device physics,molecular electronics and the applications of carbon nanotubes in molecular electronics.Future prospects and investigations required to improve the OFET performance are also involved.

  11. Wet Organic Field Effect Transistor as DNA sensor

    OpenAIRE

    Chiu, Yu-Jui

    2008-01-01

    Label-free detection of DNA has been successfully demonstrated on field effect transistor (FET) based devices. Since conducting organic materials was discovered and have attracted more and more research efforts by their profound advantages, this work will focus on utilizing an organic field effect transistor (OFET) as DNA sensor. An OFET constructed with a transporting fluidic channel, WetOFET, forms a fluid-polymer (active layer) interface where the probe DNA can be introduced. DNA hybridiza...

  12. Performance and processability of organic field effect transistors

    OpenAIRE

    Alt, Milan

    2015-01-01

    The present work addresses challenges with the performance and processability of organic semiconductors for their application in organic field-effect transistors (OFET). The results that are presented in this thesis show that combining advances in chemical material design and interface tailoring with advances in deposition and processing techniques, in order to unfold the potential of organic electronics, is a matter of engineering.

  13. SEMICONDUCTOR DEVICES: Humidity sensitive organic field effect transistor

    Science.gov (United States)

    Murtaza, I.; Karimov, Kh S.; Ahmad, Zubair; Qazi, I.; Mahroof-Tahir, M.; Khan, T. A.; Amin, T.

    2010-05-01

    This paper reports the experimental results for the humidity dependent properties of an organic field effect transistor. The organic field effect transistor was fabricated on thoroughly cleaned glass substrate, in which the junction between the metal gate and the organic channel plays the role of gate dielectric. Thin films of organic semiconductor copper phthalocynanine (CuPc) and semitransparent Al were deposited in sequence by vacuum thermal evaporation on the glass substrate with preliminarily deposited Ag source and drain electrodes. The output and transfer characteristics of the fabricated device were performed. The effect of humidity on the drain current, drain current-drain voltage relationship, and threshold voltage was investigated. It was observed that humidity has a strong effect on the characteristics of the organic field effect transistor.

  14. Organic transistors in optical displays and microelectronic applications

    NARCIS (Netherlands)

    Gelinck, G.H.; Heremans, P.; Nomoto, K.; Anthopoulos, T.D.

    2010-01-01

    Organic thin-film transistors (OTFTs) offer unprecedented opportunities for implementation in a broad range of technological applications spanning from large-volume microelectronics and optical displays to chemical and biological sensors. In this Progress Report, we review the application of organic

  15. Organic thin film transistor integration a hybrid approach

    CERN Document Server

    Li, Flora; Wu, Yiliang; Ong, Beng S

    2013-01-01

    Research on organic electronics (or plastic electronics) is driven by the need to create systems that are lightweight, unbreakable, and mechanically flexible. With the remarkable improvement in the performance of organic semiconductor materials during the past few decades, organic electronics appeal to innovative, practical, and broad-impact applications requiring large-area coverage, mechanical flexibility, low-temperature processing, and low cost. Thus, organic electronics appeal to a broad range of electronic devices and products including transistors, diodes, sensors, solar cells, lighting

  16. Flexible carbon-based ohmic contacts for organic transistors

    Science.gov (United States)

    Brandon, Erik (Inventor)

    2007-01-01

    The present invention relates to a system and method of organic thin-film transistors (OTFTs). More specifically, the present invention relates to employing a flexible, conductive particle-polymer composite material for ohmic contacts (i.e. drain and source).

  17. π-Conjugated Organic Semiconductors for Field-Effect Transistors

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-qi

    2005-01-01

    @@ 1Results and Discussion Organic semiconductors employed as active layers in field-effect transistors (FETs) are of great current interest because such FETs can potentially be fabricated at low cost, over large areas, and on flexible substrates. Such facile fabrication approaches offer a significant advantage over silicon technology in numerous applications.

  18. Conductance switching in organic ferroelectric field-effect transistors

    NARCIS (Netherlands)

    Asadi, K.; Blom, P.W.M.; Leeuw, D.M. de

    2011-01-01

    Staggered bottom-contact top-gate organic ferroelectric field-effect transistors are fabricated with poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) as ferroelectric gate and poly[bis(4-phenyl)(2,4,6- trimethylphenyl)amine] as semiconductor. Polarization reversal of the ferroelectric gate

  19. Physics of organic ferroelectric field-effect transistors

    NARCIS (Netherlands)

    Brondijk, Jakob J.; Asadi, Kamal; Blom, Paul W. M.; de Leeuw, Dago M.

    2012-01-01

    Most of the envisaged applications of organic electronics require a nonvolatile memory that can be programmed, erased, and read electrically. Ferroelectric field-effect transistors (FeFET) are especially suitable due to the nondestructive read-out and low power consumption. Here, an analytical model

  20. Electrolyte-Gated Graphene Ambipolar Frequency Multipliers for Biochemical Sensing.

    Science.gov (United States)

    Fu, Wangyang; Feng, Lingyan; Mayer, Dirk; Panaitov, Gregory; Kireev, Dmitry; Offenhäusser, Andreas; Krause, Hans-Joachim

    2016-04-13

    In this Letter, the ambipolar properties of an electrolyte-gated graphene field-effect transistor (GFET) have been explored to fabricate frequency-doubling biochemical sensor devices. By biasing the ambipolar GFETs in a common-source configuration, an input sinusoidal voltage at frequency f applied to the electrolyte gate can be rectified to a sinusoidal wave at frequency 2f at the drain electrode. The extraordinary high carrier mobility of graphene and the strong electrolyte gate coupling provide the graphene ambipolar frequency doubler an unprecedented unity gain, as well as a detection limit of ∼4 pM for 11-mer single strand DNA molecules in 1 mM PBS buffer solution. Combined with an improved drift characteristics and an enhanced low-frequency 1/f noise performance by sampling at doubled frequency, this good detection limit suggests the graphene ambipolar frequency doubler a highly promising biochemical sensing platform. PMID:26928906

  1. Organic Field-effect Transistors Based on Tetrathiafulvalene Derivatives

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Restults Tetrathiafulvalene (TTF) and its derivatives have been extensively investigated in the field of organic conductors and superconductors since 1973. Recently, their application in organic field-effect transistors (OFETs) has attracted considerable attention. So far, on the one hand, the fabrication techniques of the TTF-based FETs have been primarily limited to high vacuum evaporation, which is a relatively expensive process. On the other hand, low FET performances, such as the low on/off ratio...

  2. Advances in organic field-effect transistors and integrated circuits

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years. In this article we introduce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress. Finally, the prospects and problems of OFETs are discussed.

  3. Advances in organic field-effect transistors and integrated circuits

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; JI ZhuoYu; LIU Ming; SHANG LiWei; LIU Ge; LIU XingHua; LIU Jiang; PENG YingQuan

    2009-01-01

    Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years.In this article we intro-duce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress.Finally, the prospects and problems of OFETs are discussed.

  4. Vertical Organic Field-Effect Transistors for Integrated Optoelectronic Applications.

    Science.gov (United States)

    Yu, Hyeonggeun; Dong, Zhipeng; Guo, Jing; Kim, Doyoung; So, Franky

    2016-04-27

    Direct integration of a vertical organic field-effect transistor (VOFET) and an optoelectronic device offers a single stacked, low power optoelectronic VOFET with high aperture ratios. However, a functional optoelectronic VOFET could not be realized because of the difficulty in fabricating transparent source and gate electrodes. Here, we report a VOFET with an on/off ratio up to 10(5) as well as output current saturation by fabricating a transparent gate capacitor consisting of a perforated indium tin oxide (ITO) source electrode, HfO2 gate dielectric, and ITO gate electrode. Effects of the pore size and the pore depth within the porous ITO electrodes on the on/off characteristic of a VOFET are systematically explained in this work. By combining a phosphorescent organic light-emitting diode with an optimized VOFET structure, a vertical organic light-emitting transistor with a luminance on/off ratio of 10(4) can be fabricated. PMID:27082815

  5. Organic field-effect transistors using single crystals

    Directory of Open Access Journals (Sweden)

    Tatsuo Hasegawa and Jun Takeya

    2009-01-01

    Full Text Available Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs, the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20–40 cm2 Vs−1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps.

  6. Organic field-effect transistors using single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Tatsuo [Photonics Research Institute (PRI), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Takeya, Jun, E-mail: t-hasegawa@aist.go.j, E-mail: takeya@chem.sci.osaka-u.ac.j [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043 (Japan)

    2009-04-15

    Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm{sup 2} Vs{sup -1}, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps. (topical review)

  7. Organic field-effect transistors using single crystals

    International Nuclear Information System (INIS)

    Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm2 Vs-1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps. (topical review)

  8. TOPICAL REVIEW: Organic field-effect transistors using single crystals

    Science.gov (United States)

    Hasegawa, Tatsuo; Takeya, Jun

    2009-04-01

    Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm2 Vs-1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps.

  9. Organic single-crystal field-effect transistors

    Directory of Open Access Journals (Sweden)

    Colin Reese

    2007-03-01

    Full Text Available Organic molecular crystals hold great promise for the rational development of organic semiconductor materials. Their long-range order not only reveals the performance limits of organic materials, but also provides unique insight into their intrinsic transport properties. The field-effect transistor (FET has served as a versatile tool for electrical characterization of many facets of their performance. In the last few years, breakthroughs in single-crystal FET fabrication techniques have enabled the realization of field-effect mobilities far surpassing amorphous Si, observation of the Hall effect in an organic material, and the study of transport as an explicit function of molecular packing and chemical structure.

  10. Orientation selectivity in a multi-gated organic electrochemical transistor

    Science.gov (United States)

    Gkoupidenis, Paschalis; Koutsouras, Dimitrios A.; Lonjaret, Thomas; Fairfield, Jessamyn A.; Malliaras, George G.

    2016-06-01

    Neuromorphic devices offer promising computational paradigms that transcend the limitations of conventional technologies. A prominent example, inspired by the workings of the brain, is spatiotemporal information processing. Here we demonstrate orientation selectivity, a spatiotemporal processing function of the visual cortex, using a poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) organic electrochemical transistor with multiple gates. Spatially distributed inputs on a gate electrode array are found to correlate with the output of the transistor, leading to the ability to discriminate between different stimuli orientations. The demonstration of spatiotemporal processing in an organic electronic device paves the way for neuromorphic devices with new form factors and a facile interface with biology.

  11. Liquid crystals for organic thin-film transistors

    OpenAIRE

    Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-ichi

    2015-01-01

    Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,...

  12. Enhancement of ambipolar characteristics in single-walled carbon nanotubes using C{sub 60} and fabrication of logic gates

    Energy Technology Data Exchange (ETDEWEB)

    Park, Steve [Department of Materials Science and Engineering, Stanford University, Durand Building, 496 Lomita Mall, Stanford, California 94305-4034 (United States); Nam, Ji Hyun [Department of Electrical Engineering, Stanford University, David Packard Building, 350 Serra Mall, Mail Code: 9505, Stanford, California 94305-9505 (United States); Koo, Ja Hoon; Lei, Ting; Bao, Zhenan, E-mail: zbao@stanford.edu [Department of Chemical Engineering, Stanford University, Shriram Center, 443 Via Ortega, Room 307, Stanford, California 94305-4145 (United States)

    2015-03-09

    We demonstrate a technique to convert p-type single-walled carbon nanotube (SWNT) network transistor into ambipolar transistor by thermally evaporating C{sub 60} on top. The addition of C{sub 60} was observed to have two effects in enhancing ambipolar characteristics. First, C{sub 60} served as an encapsulating layer that enhanced the ambipolar characteristics of SWNTs. Second, C{sub 60} itself served as an electron transporting layer that contributed to the n-type conduction. Such a dual effect enables effective conversion of p-type into ambipolar characteristics. We have fabricated inverters using our SWNT/C{sub 60} ambipolar transistors with gain as high as 24, along with adaptive NAND and NOR logic gates.

  13. Inkjet printing of organic transistor devices

    OpenAIRE

    Basiricò, Laura

    2012-01-01

    In the last two decades inkjet printing passed from the field of graphic art and newspaper industry to that of organic and flexible electronics, as a manufacturing tool, becoming a major topic in scientific research. The appeal of this kind of technology is mainly due to its low cost, non-contact and additive approach, which makes it surely the most promising technique over the other technologies of Printed Electronics. The focus of this thesis is the optimization of the printing proces...

  14. AMBIPOLAR DIFFUSION REVISITED

    Directory of Open Access Journals (Sweden)

    F. C. Adams

    2009-01-01

    Full Text Available This contribution re-examines the problem of ambipolar di usion as a mechanism for the production and runaway evolution (collapse of centrally condensed molecular cloud cores. The principal calculation applies in the geometric limit of a highly attened core and allows for a semi-analytic treatment of the full problem. In this formulation, the ambipolar di usion regime of evolution for negative times (t 0. This treatment shows that the resulting cores display non-zero, but sub-magnetosonic, inward velocities at the end of the di usion epoch, in agreement with current observations. This work derives an analytic relationship between the dimensionless mass to ux ratio 0 = f0-1 0 of the central regions produced by runaway core condensation and the dimensionless rate of ambipolar di usion e; cores going into collapse typically have values of mass-to- ux ratio 0 = 2. Next we show that ambipolar di usion takes place more quickly in the presence of turbulent uctuations, i.e., the e ective value of the di usion constan E can be enhanced by turbulence. We also study self-similar collapse with the inclusion of nonzero initial inward velocities. Taken together, these ndings show that the resulting theory provides a viable working paradigm for the formation of molecular cloud cores and their subsequent collapse to form stars and planetary systems.

  15. Pentacene Organic-Thin-Film Field-Effect Transistors

    Institute of Scientific and Technical Information of China (English)

    张素梅; 石家纬; 刘明大; 李靖; 郭树旭; 王伟

    2004-01-01

    We have fabricated organic thin-film transistors using the small-molecule polycyclic aromatic hydrocarbon pentacene as an active material. Devices were fabricated on glass substrates by using rf-magnetron sputtered amorphous aluminium as the gate electrode, and gelatinized polyimide as the gate dielectric with physical vapour grown pentacene thin films pasted on it as the active layer, then using rf-magnetron sputtered amorphous aluminium as the source and drain contacts. Field effect mobility and threshold voltage is 0.092 cm2 /Vs and 14.5 V,respectively. On-off current ratio is nearly 103.

  16. Touching polymer chains by organic field-effect transistors

    OpenAIRE

    Wei Shao; Huanli Dong; Zhigang Wang; Wenping Hu

    2014-01-01

    Organic field-effect transistors (OFETs) are used to directly “touch” the movement and dynamics of polymer chains, and then determine Tg. As a molecular-level probe, the conducting channel of OFETs exhibits several unique advantages: 1) it directly detects the motion and dynamics of polymer chain at T g ; 2) it allows the measurement of size effects in ultrathin polymer films (even down to 6 nm), which bridges the gap in understanding effects between surface and interface. This facile and rel...

  17. Electrolyte-gated organic synapse transistor interfaced with neurons

    CERN Document Server

    Desbief, Simon; Casalini, Stefano; Guerin, David; Tortorella, Silvia; Barbalinardo, Marianna; Kyndiah, Adrica; Murgia, Mauro; Cramer, Tobias; Biscarini, Fabio; Vuillaume, Dominique

    2016-01-01

    We demonstrate an electrolyte-gated hybrid nanoparticle/organic synapstor (synapse-transistor, termed EGOS) that exhibits short-term plasticity as biological synapses. The response of EGOS makes it suitable to be interfaced with neurons: short-term plasticity is observed at spike voltage as low as 50 mV (in a par with the amplitude of action potential in neurons) and with a typical response time in the range of tens milliseconds. Human neuroblastoma stem cells are adhered and differentiated into neurons on top of EGOS. We observe that the presence of the cells does not alter short-term plasticity of the device.

  18. Multicolored Nanofiber Based Organic Light-Emitting Transistor

    DEFF Research Database (Denmark)

    With Jensen, Per Baunegaard; Kjelstrup-Hansen, Jakob; Tavares, Luciana;

    For optoelectronic applications, organic semiconductors have several advantages over their inorganic counterparts such as facile synthesis, tunability via synthetic chemistry, and low temperature processing. Self-assembled, molecular crystalline nanofibers are of particular interest as they could...... form ultra-small light-emitters in future nanophotonic applications. Such organic nanofibers exhibit many interesting optical properties including polarized photo- and electroluminescence, waveguiding, and emission color tunability. We here present a first step towards a multicolored, electrically...... driven device by combining nanofibers made from two different molecules, parahexaphenylene (p6P) and 5,5´-Di-4-biphenyl-2,2´-bithiophene (PPTTPP), which emits blue and green light, respectively. The organic nanofibers are implemented on a bottom gate/bottom contact field-effect transistor platform using...

  19. Dynamics of threshold voltage shifts in organic and amorphous silicon field-effect transistors

    NARCIS (Netherlands)

    Mathijssen, Simon G. J.; Colle, Michael; Gomes, Henrique; Smits, Edsger C. P.; de Boer, Bert; McCulloch, Iain; Bobbert, Peter A.; de Leeuw, Dago M.; Cölle, Michael

    2007-01-01

    The electrical instability of organic field-effect transistors is investigated. We observe that the threshold-voltage shift (see figure) shows a stretched-exponential time dependence under an applied gate bias. The activation energy of 0.6 eV is common for our and all other organic transistors repor

  20. Synaptic plasticity functions in an organic electrochemical transistor

    Science.gov (United States)

    Gkoupidenis, Paschalis; Schaefer, Nathan; Strakosas, Xenofon; Fairfield, Jessamyn A.; Malliaras, George G.

    2015-12-01

    Synaptic plasticity functions play a crucial role in the transmission of neural signals in the brain. Short-term plasticity is required for the transmission, encoding, and filtering of the neural signal, whereas long-term plasticity establishes more permanent changes in neural microcircuitry and thus underlies memory and learning. The realization of bioinspired circuits that can actually mimic signal processing in the brain demands the reproduction of both short- and long-term aspects of synaptic plasticity in a single device. Here, we demonstrate the implementation of neuromorphic functions similar to biological memory, such as short- to long-term memory transition, in non-volatile organic electrochemical transistors (OECTs). Depending on the training of the OECT, the device displays either short- or long-term plasticity, therefore, exhibiting non von Neumann characteristics with merged processing and storing functionalities. These results are a first step towards the implementation of organic-based neuromorphic circuits.

  1. Organic nano-floating-gate transistor memory with metal nanoparticles

    Science.gov (United States)

    Van Tho, Luu; Baeg, Kang-Jun; Noh, Yong-Young

    2016-04-01

    Organic non-volatile memory is advanced topics for various soft electronics applications as lightweight, low-cost, flexible, and printable solid-state data storage media. As a key building block, organic field-effect transistors (OFETs) with a nano-floating gate are widely used and promising structures to store digital information stably in a memory cell. Different types of nano-floating-gates and their various synthesis methods have been developed and applied to fabricate nanoparticle-based non-volatile memory devices. In this review, recent advances in the classes of nano-floating-gate OFET memory devices using metal nanoparticles as charge-trapping sites are briefly reviewed. Details of device fabrication, characterization, and operation mechanisms are reported based on recent research activities reported in the literature.

  2. Theoretical study of stability and charge-transport properties of coronene molecule and some of its halogenated derivatives: a path to ambipolar organic-based materials?

    Science.gov (United States)

    Sancho-García, J C; Pérez-Jiménez, A J

    2014-10-01

    We have carefully investigated the structural and electronic properties of coronene and some of its fluorinated and chlorinated derivatives, including full periphery substitution, as well as the preferred orientation of the non-covalent dimer structures subsequently formed. We have paid particular attention to a set of methodological details, to first obtain single-molecule magnitudes as accurately as possible, including next the use of modern dispersion-corrected methods to tackle the corresponding non-covalently bound dimers. Generally speaking, this class of compounds is expected to self-assembly in neighboring π-stacks with dimer stabilization energies ranging from -20 to -30 kcal mol(-1) at close distances around 3.0-3.3 Å. Then, in a further step, we have also calculated hole and electron transfer rates of some suitable candidates for ambipolar materials, and corresponding charge mobility values, which are known to critically depend on the supramolecular organization of the samples. For coronene and per-fluorinated coronene, we have found high values for their hopping rates, although slightly smaller for the latter due to an increase (decrease) of the reorganization energies (electronic couplings). PMID:25296829

  3. Probing electric fields within organic transistors by nonlinear optics

    Science.gov (United States)

    Miranda, Paulo B.; Motti, Silvia G.; Gomes, Douglas J. C.

    2015-03-01

    Organic field-effect transistors (OFETs) are important building blocks in many organic devices, but further improvements in their performance will require a detailed knowledge of their operation mechanism. Thus mapping the electric fields in OFETs, both in the active organic layer and inside the gate dielectric, will allow a direct comparison with theoretical OFET models and guide advances in device engineering. The nonlinear optical processes of sum-frequency generation (SFG) and second-harmonic generation (SHG) may be used to probe electric fields in OFETs. With a proper choice of pump wavelength, SHG can selectively probe the field component along the OFET channel, inside the organic semiconductor. In contrast, SFG may probe the field within any organic material by selecting a specific molecular vibration and monitoring the field-enhanced SFG signal. Here we investigate OFETs fabricated with a polythiophene derivative (P3HT) on silicon substrates and with the insulating polymer PMMA for the dielectric layer. Both the strength and sign of the electric field in PMMA can be determined, yielding a direct probe of charge accumulation along the OFET channel. An extension of this technique to map the spatial distribution of accumulated charge along the channel will also be discussed. Work funded by FAPESP and CNPq (Brazil).

  4. Preparation of organic thin-film field effect transistor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The organic thin-film field effect transistor was prepared through vacuum deposition by using teflon as di-electric material. Indium-tin-oxide acted as the source and drain electrodes. Copper phthalocyanine and teflon were used as the semiconductor layer and dielectric layer, respectively. The gate electrode was made of Ag. The channel length between the source and drain was 50 μm. After preparing the source and drain electrodes by lithography, the copper phthalocyanine layer, teflon layer and Ag layerwere prepared by vacuum deposition sequentially. The field effect electron mobility of the device reached 1.1×10ˉ6 cm2/(V@s), and the on/off current ratio reached 500.

  5. Ultrathin flexible memory devices based on organic ferroelectric transistors

    Science.gov (United States)

    Sugano, Ryo; Hirai, Yoshinori; Tashiro, Tomoya; Sekine, Tomohito; Fukuda, Kenjiro; Kumaki, Daisuke; Domingues dos Santos, Fabrice; Miyabo, Atsushi; Tokito, Shizuo

    2016-10-01

    Here, we demonstrate ultrathin, flexible nonvolatile memory devices with excellent durability under compressive strain. Ferroelectric-gate field-effect transistors (FeFETs) employing organic semiconductor and polymer ferroelectric layers are fabricated on a 1-µm-thick plastic film substrate. The FeFETs are characterized by measuring their transfer characteristics, programming time, and data retention time. The data retention time is almost unchanged even when a 50% compressive strain is applied to the devices. To clarify the origin of the excellent durability of the devices against compressive strain, an intermediate plane is calculated. From the calculation result, the intermediate plane is placed close to the channel region of the FeFETs. The high flexibility of the ferroelectric polymer and ultrathin device structure contributes to achieving a bending radius of 0.8 µm without the degradation of memory characteristics.

  6. Passive micromixers and organic electrochemical transistors for biosensor applications

    Science.gov (United States)

    Kanakamedala, Senaka Krishna

    Fluid handling at the microscale has greatly affected different fields such as biomedical, pharmaceutical, biochemical engineering and environmental monitoring due to its reduced reagent consumption, portability, high throughput, lower hardware cost and shorter analysis time compared to large devices. The challenges associated with mixing of fluids in microscale enabled us in designing, simulating, fabricating and characterizing various micromixers on silicon and flexible polyester substrates. The mixing efficiency was evaluated by injecting the fluids through the two inlets and collecting the sample at outlet. The images collected from the microscope were analyzed, and the absorbance of the color product at the outlet was measured to quantify the mixing efficacy. A mixing efficiency of 96% was achieved using a flexible disposable micromixer. The potential for low-cost processing and the device response tuning using chemical doping or synthesis opened doorways to use organic semiconductor devices as transducers in chemical and biological sensor applications. A simple, inexpensive organic electrochemical transistor (OECT) based on conducting polymer poly(3,4- ethyelenedioxythiphene) poly(styrene sulfonate) (PEDOT:PSS) was fabricated using a novel one step fabrication method. The developed transistor was used as a biosensor to detect glucose and glutamate. The developed glucose sensor showed a linear response for the glucose levels ranging from 1 muM-10 mM and showed a decent response for the glucose levels similar to those found in human saliva and to detect glutamate released from brain tumor cells. The developed glutamate sensor was used to detect the glutamate released from astrocytes and glioma cells after stimulation, and the results are compared with fluorescent spectrophotometer. The developed sensors employ simple fabrication, operate at low potentials, utilize lower enzyme concentrations, do not employ enzyme immobilization techniques, require only 5 muL of

  7. Low-Voltage, Low-Power, Organic Light-Emitting Transistors for Active Matrix Displays

    Science.gov (United States)

    McCarthy, M. A.; Liu, B.; Donoghue, E. P.; Kravchenko, I.; Kim, D. Y.; So, F.; Rinzler, A. G.

    2011-04-01

    Intrinsic nonuniformity in the polycrystalline-silicon backplane transistors of active matrix organic light-emitting diode displays severely limits display size. Organic semiconductors might provide an alternative, but their mobility remains too low to be useful in the conventional thin-film transistor design. Here we demonstrate an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors. The high level of performance is enabled by a single-wall carbon nanotube network source electrode that permits integration of the drive transistor and the light emitter into an efficient single stacked device. The performance demonstrated is comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.

  8. Printed organic thin-film transistor-based integrated circuits

    International Nuclear Information System (INIS)

    Organic electronics is moving ahead on its journey towards reality. However, this technology will only be possible when it is able to meet specific criteria including flexibility, transparency, disposability and low cost. Printing is one of the conventional techniques to deposit thin films from solution-based ink. It is used worldwide for visual modes of information, and it is now poised to enter into the manufacturing processes of various consumer electronics. The continuous progress made in the field of functional organic semiconductors has achieved high solubility in common solvents as well as high charge carrier mobility, which offers ample opportunity for organic-based printed integrated circuits. In this paper, we present a comprehensive review of all-printed organic thin-film transistor-based integrated circuits, mainly ring oscillators. First, the necessity of all-printed organic integrated circuits is discussed; we consider how the gap between printed electronics and real applications can be bridged. Next, various materials for printed organic integrated circuits are discussed. The features of these circuits and their suitability for electronics using different printing and coating techniques follow. Interconnection technology is equally important to make this product industrially viable; much attention in this review is placed here. For high-frequency operation, channel length should be sufficiently small; this could be achievable with a combination of surface treatment-assisted printing or laser writing. Registration is also an important issue related to printing; the printed gate should be perfectly aligned with the source and drain to minimize parasitic capacitances. All-printed organic inverters and ring oscillators are discussed here, along with their importance. Finally, future applications of all-printed organic integrated circuits are highlighted. (paper)

  9. Studying the operation characteristics and structure of vertical channel copper-phthalocyanine organic semiconductor transistor

    Institute of Scientific and Technical Information of China (English)

    ZHU Min; SONG Ming-xin; GUI Tai-long; WANG Xuan; YIN Jing-hua; WANG Dong-xing; ZHAO Hong

    2005-01-01

    The creation of Au/CuPc/Al/CuPc/structure is a perpendicular type electricity found in the channel of organic static induction transistor. In the following we analyze transistor operation characteristics and machine structural relation. The results express that the transistor drives the voltage low and has no-saturation currentvoltage characteristics. Its operation characteristics are dependant on gate bias voltage and the construction of the aluminum electrode.The vertical channel of organic static induction transistor (OSIT) , with structure of Au/CuPc/Al/CuPc/Cu, has been determined. According to the test results, the relation of its operation characteristics and device structure was analyzed. The results show that this transistor has a low driving voltage and unsaturation Ⅰ-Ⅴ characteristics. Its operation characteristics are dependant on gate bias voltage and the structure of the aluminum electrode.

  10. Stabilization of organic thin film transistors by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Fraboni, B., E-mail: beatrice.fraboni@unibo.it [CNISM and Dipartimento di Fisica, Universita di Bologna, viale Berti Pichat 6/2, 40127 Bologna (Italy); Cosseddu, P. [Dipartimento di Ingegneria Elettrica ed Elettronica, Universita di Cagliari, piazza d' Armi, 09123 Cagliari, Italy and CNR-INFM S3 via Campi 213/a 41100 Modena (Italy); Wang, Y.Q.; Schulze, R.K. [Los Alamos National Laboratory MS-K771 Los Alamos NM 87545 (United States); Cavallini, A. [CNISM and Dipartimento di Fisica, Universita di Bologna, viale Berti Pichat 6/2, 40127 Bologna (Italy); Nastasi, M. [Los Alamos National Laboratory MS-K771 Los Alamos NM 87545 (United States); Bonfiglio, A. [Dipartimento di Ingegneria Elettrica ed Elettronica, Universita di Cagliari, piazza d' Armi, 09123 Cagliari, Italy and CNR-INFM S3 via Campi 213/a 41100 Modena (Italy)

    2012-08-01

    We report on the effects of low energy ion implantation (N and Ne) in the reduction and control of the degradation of pentacene organic thin film transistors (OTFTs) due to the exposure to atmosphere (i.e. oxygen and water). We have observed that a controlled damage depth distribution preserves the functionality of the devices, even if ion implantation induces significant molecular structure modifications, in particular a combination of dehydrogenation and carbonification effects. No relevant changes in the pentacene thin film thickness have been observed. The two major transport parameters that characterize OTFT performance are the carrier mobility and the threshold voltage. We have monitored the effectiveness of this process in stabilizing the device by monitoring the carrier mobility and the threshold voltage over a long time (over 2000 h). Finally, we have assessed by depth resolved X-ray Photoemission Spectroscopy analyses that, by selectively implanting with ions that can react with the hydrocarbon matrix (e.g. N{sup +}), it is possible to locally modify the charge distribution within the organic layer.

  11. Tailoring Functional Interlayers in Organic Field-Effect Transistor Biosensors.

    Science.gov (United States)

    Magliulo, Maria; Manoli, Kyriaki; Macchia, Eleonora; Palazzo, Gerardo; Torsi, Luisa

    2015-12-01

    This review aims to provide an update on the development involving dielectric/organic semiconductor (OSC) interfaces for the realization of biofunctional organic field-effect transistors (OFETs). Specific focus is given on biointerfaces and recent technological approaches where biological materials serve as interlayers in back-gated OFETs for biosensing applications. Initially, to better understand the effects produced by the presence of biomolecules deposited at the dielectric/OSC interfacial region, the tuning of the dielectric surface properties by means of self-assembled monolayers is discussed. Afterward, emphasis is given to the modification of solid-state dielectric surfaces, in particular inorganic dielectrics, with biological molecules such as peptides and proteins. Special attention is paid on how the presence of an interlayer of biomolecules and bioreceptors underneath the OSC impacts on the charge transport and sensing performance of the device. Moreover, naturally occurring materials, such as carbohydrates and DNA, used directly as bulk gating materials in OFETs are reviewed. The role of metal contact/OSC interface in the overall performance of OFET-based sensors is also discussed. PMID:25429859

  12. Significant Improvement of Organic Thin-Film Transistor Mobility Utilizing an Organic Heterojunction Buffer Layer

    Institute of Scientific and Technical Information of China (English)

    PAN Feng; QIAN Xian-Rui; HUANG Li-Zhen; WANG Hai-Bo; YAN Dong-Hang

    2011-01-01

    High-mobility vanadyl phthalocyanine (VOPc)/5,5″′-bis(4-fluorophenyl)-2,2′:5′,2″:5″,2″′-quaterthiophene (F2-P4T) thin-film transistors are demonstrated by employing a copper hexadecafluorophthalocyanine (F16 CuPc)/copper phthalocyanine (CuPc) heterojunction unit,which are fabricated at different substrate temperatures,as a buffer layer. The highest mobility of 4.08cm2/Vs is achieved using a F16CuPc/CuPc organic heterojunction buffer layer fabricated at high substrate temperature.Compared with the random small grain-like morphology of the room-temperature buffer layer,the high-temperature organic heterojunction presents a large-sized fiber-like film morphology,resulting in an enhanced conductivity.Thus the contact resistance of the transistor is significantly reduced and an obvious improvement in device mobility is obtained.

  13. Theory aided design and analysis of dielectric and semiconductor components for organic field-effect transistors

    Science.gov (United States)

    Dibenedetto, Sara Arlene

    Perfluoroacyl/acyl-derivatized quaterthiophens are developed and synthesized. The frontier molecular orbital energies of these compounds are studied by optical spectroscopy and electrochemistry while solid-state/film properties are investigated by thermal analysis, x-ray diffraction, and scanning electron microscopy. Organic thin film transistors (OTFTs) performance parameters are discussed in terms of the interplay between semiconductor molecular energetics and film morphologies/microstructures. The majority charge carrier type and mobility exhibit a strong correlation with the regiochemistry of perfluoroarene incorporation. In quaterthiophene-based semiconductors, carbonyl-functionalization allows tuning of the majority carrier type from p-type to ambipolar and to n-type. In situ conversion of a p-type semiconducting film to n-type film is also demonstrated. The design of chemical and film microstructural alternative hybrid organic-inorganic gate dielectrics is described using the classic Clausius-Mossotti relation. The Maxwell-Wagner effective medium model is used to compute the effective dielectric permittivity of two types of dielectrics self-assembled nanodielectrics (SANDs) and crosslinked polymer blends (CPBs). In these calculations showing good agreement between theory and experiment, it is found that greater capacitances should be achievable with mixed composites than with layered composites. With this insight, a series of mixed metal oxide-polyolefin nanocomposites is synthesized via in-situ olefin polymerization using the single-site metallocene catalysts. By integrating organic and inorganic constituents, the resulting hybrid material exhibit high permittivity (from the inorganic inclusions) and high breakdown strength, mechanical flexibility, and facile processability (from the polymer matrices). In order to better optimize the capacitance and leakage current of hybrid organic-inorganic dielectrics, the capacitance, leakage current and OFET gate

  14. High mobility polymer gated organic field effect transistor using zinc phthalocyanine

    Indian Academy of Sciences (India)

    K R Rajesh; V Kannan; M R Kim; Y S Chae; J K Rhee

    2014-02-01

    Organic thin film transistors were fabricated using evaporated zinc phthalocyanine as the active layer. Parylene film prepared by chemical vapour deposition was used as the organic gate insulator. The annealing of the samples was performed at 120°C for 3 h. At room temperature, these transistors exhibit -type conductivity with field-effect mobilities ranging from 0.025–0.037 cm2/Vs and a (on/off) ratio of ∼ 103. The effect of annealing on transistor characteristics is discussed.

  15. Self-standing chitosan films as dielectrics in organic thin-film transistors

    Directory of Open Access Journals (Sweden)

    J. Morgado

    2013-12-01

    Full Text Available Organic thin film transistors, using self-standing 50 µm thick chitosan films as dielectric, are fabricated using sublimed pentacene or two conjugated polymers deposited by spin coating as semiconductors. Field-effect mobilities are found to be similar to values obtained with other dielectrics and, in the case of pentacene, a value (0.13 cm2/(V•s comparable to high performing transistors was determined. In spite of the low On/Off ratios (a maximum value of 600 was obtained for the pentacene-based transistors, these are promising results for the area of sustainable organic electronics in general and for biocompatible electronics in particular.

  16. Research Update: Electrical monitoring of cysts using organic electrochemical transistors

    Energy Technology Data Exchange (ETDEWEB)

    Huerta, M.; Rivnay, J.; Ramuz, M.; Hama, A.; Owens, R. M. [Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, MOC, 13541 Gardanne (France)

    2015-03-01

    Organotypic three-dimensional (3D) cell culture models have the potential to act as surrogate tissues in vitro, both for basic research and for drug discovery/toxicology. 3D cultures maintain not only 3D architecture but also cell-cell and cell extracellular matrix interactions, particularly when grown in cysts or spheroids. Characterization of cell cultures grown in 3D formats, however, provides a significant challenge for cell biologists due to the incompatibility of these structures with commonly found optical or electronic monitoring systems. Electronic impedance spectroscopy is a cell culture monitoring technique with great potential; however, it has not been possible to integrate 3D cultures with commercially available systems to date. Cyst-like 3D cultures are particularly challenging due to their small size and difficulty in manipulation. Herein, we demonstrate isolation of cyst-like 3D cultures by capillarity and subsequent integration with the organic electrochemical transistor for monitoring the integrity of these structures. We show not only that this versatile device can be adapted to the cyst format for measuring resistance and, therefore, the quality of the cysts, but also can be used for quantitative monitoring of the effect of toxic compounds on cells in a 3D format. The ability to quantitatively predict effects of drugs on 3D cultures in vitro has large future potential for the fields of drug discovery and toxicology.

  17. Research Update: Electrical monitoring of cysts using organic electrochemical transistors

    Directory of Open Access Journals (Sweden)

    M. Huerta

    2015-03-01

    Full Text Available Organotypic three-dimensional (3D cell culture models have the potential to act as surrogate tissues in vitro, both for basic research and for drug discovery/toxicology. 3D cultures maintain not only 3D architecture but also cell-cell and cell extracellular matrix interactions, particularly when grown in cysts or spheroids. Characterization of cell cultures grown in 3D formats, however, provides a significant challenge for cell biologists due to the incompatibility of these structures with commonly found optical or electronic monitoring systems. Electronic impedance spectroscopy is a cell culture monitoring technique with great potential; however, it has not been possible to integrate 3D cultures with commercially available systems to date. Cyst-like 3D cultures are particularly challenging due to their small size and difficulty in manipulation. Herein, we demonstrate isolation of cyst-like 3D cultures by capillarity and subsequent integration with the organic electrochemical transistor for monitoring the integrity of these structures. We show not only that this versatile device can be adapted to the cyst format for measuring resistance and, therefore, the quality of the cysts, but also can be used for quantitative monitoring of the effect of toxic compounds on cells in a 3D format. The ability to quantitatively predict effects of drugs on 3D cultures in vitro has large future potential for the fields of drug discovery and toxicology.

  18. Bioinspired peptide nanostructures for organic field-effect transistors.

    Science.gov (United States)

    Cipriano, Thiago; Knotts, Grant; Laudari, Amrit; Bianchi, Roberta C; Alves, Wendel A; Guha, Suchismita

    2014-12-10

    Peptide-based nanostructures derived from natural amino acids are superior building blocks for biocompatible devices as they can be used in a bottom-up process without the need for expensive lithography. A dense nanostructured network of l,l-diphenylalanine (FF) was synthesized using the solid-vapor-phase technique. Formation of the nanostructures and structure-phase relationship were investigated by electron microscopy and Raman scattering. Thin films of l,l-diphenylalanine micro/nanostructures (FF-MNSs) were used as the dielectric layer in pentacene-based field-effect transistors (FETs) and metal-insulator-semiconductor diodes both in bottom-gate and in top-gate structures. Bias stress studies show that FF-MNS-based pentacene FETs are more resistant to degradation than pentacene FETs using FF thin film (without any nanostructures) as the dielectric layer when both are subjected to sustained electric fields. Furthermore, it is demonstrated that the FF-MNSs can be functionalized for detection of enzyme-analyte interactions. This work opens up a novel and facile route toward scalable organic electronics using peptide nanostructures as scaffolding and as a platform for biosensing. PMID:25376495

  19. Textile Organic Electrochemical Transistors as a Platform for Wearable Biosensors

    Science.gov (United States)

    Gualandi, I.; Marzocchi, M.; Achilli, A.; Cavedale, D.; Bonfiglio, A.; Fraboni, B.

    2016-01-01

    The development of wearable chemical sensors is receiving a great deal of attention in view of non-invasive and continuous monitoring of physiological parameters in healthcare applications. This paper describes the development of a fully textile, wearable chemical sensor based on an organic electrochemical transistor (OECT) entirely made of conductive polymer (PEDOT:PSS). The active polymer patterns are deposited into the fabric by screen printing processes, thus allowing the device to actually “disappear” into it. We demonstrate the reliability of the proposed textile OECTs as a platform for developing chemical sensors capable to detect in real-time various redox active molecules (adrenaline, dopamine and ascorbic acid), by assessing their performance in two different experimental contexts: i) ideal operation conditions (i.e. totally dipped in an electrolyte solution); ii) real-life operation conditions (i.e. by sequentially adding few drops of electrolyte solution onto only one side of the textile sensor). The OECTs response has also been measured in artificial sweat, assessing how these sensors can be reliably used for the detection of biomarkers in body fluids. Finally, the very low operating potentials (<1 V) and absorbed power (~10−4 W) make the here described textile OECTs very appealing for portable and wearable applications. PMID:27667396

  20. Organic electrochemical transistors for cell-based impedance sensing

    Science.gov (United States)

    Rivnay, Jonathan; Ramuz, Marc; Leleux, Pierre; Hama, Adel; Huerta, Miriam; Owens, Roisin M.

    2015-01-01

    Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal.

  1. Organic electrochemical transistors for cell-based impedance sensing

    Energy Technology Data Exchange (ETDEWEB)

    Rivnay, Jonathan, E-mail: rivnay@emse.fr, E-mail: owens@emse.fr; Ramuz, Marc; Hama, Adel; Huerta, Miriam; Owens, Roisin M., E-mail: rivnay@emse.fr, E-mail: owens@emse.fr [Department of Bioelectronics, Ecole des Mines de St. Etienne, 13541 Gardanne (France); Leleux, Pierre [Department of Bioelectronics, Ecole des Mines de St. Etienne, 13541 Gardanne (France); Microvitae Technologies, Pole d' Activite Y. Morandat, 13120 Gardanne (France)

    2015-01-26

    Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal.

  2. Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole, and fluorene units

    Science.gov (United States)

    Pearson, Christopher; Bowen, Leon; Lee, Myung Won; Fisher, Alison L.; Linton, Katherine E.; Bryce, Martin R.; Petty, Michael C.

    2013-01-01

    We report on the mechanism of operation of organic thin film resistive memory architectures based on an ambipolar compound consisting of oxadiazole, carbazole, and fluorene units. Cross-sections of the devices have been imaged by electron microscopy both before and after applying a voltage. The micrographs reveal the growth of filaments, with diameters of 50 nm–100 nm, on the metal cathode. We suggest that these are formed by the drift of aluminium ions from the anode and are responsible for the observed switching and negative differential resistance phenomena in the memory devices.

  3. Temperature Dependence of Field-Effect Mobility in Organic Thin-Film Transistors: Similarity to Inorganic Transistors.

    Science.gov (United States)

    Okada, Jun; Nagase, Takashi; Kobayashi, Takashi; Naito, Hiroyoshi

    2016-04-01

    Carrier transport in solution-processed organic thin-film transistors (OTFTs) based on dioctylbenzothienobenzothiophene (C8-BTBT) has been investigated in a wide temperature range from 296 to 10 K. The field-effect mobility shows thermally activated behavior whose activation energy becomes smaller with decreasing temperature. The temperature dependence of field-effect mobility found in C8-BTBT is similar to that of others materials: organic semiconducting polymers, amorphous oxide semiconductors and hydrogenated amorphous silicon. These results indicate that hopping transport between isoenergetic localized states becomes dominated in a low temperature regime in these materials. PMID:27451607

  4. Charge transfer at organic-organic heterojunctions, and remote doping of a pentacene transistor

    Science.gov (United States)

    Zhao, Wei

    (tfd)3). A remotely doped pentacene transistor, based on this type of hetero-structure, exhibits increased conductivity, decreased activation energy for carrier hopping, and enhanced mobility, compared to an undoped transistor. Another featured improvement of the remotely doped transistor is that it can be reasonably switched off by placing an undoped interlayer in the structure. Our preliminary results show chemical doping technology can potentially benefit the organic thin film transistors.

  5. Photoactive self-assembled monolayers for optically switchable organic thin-film transistors

    OpenAIRE

    Salinas, Michael; Halik, Marcus

    2013-01-01

    We investigate the photoconductive and photovoltaic effects in organic thin-film transistors with thin hybrid dielectrics composed of aluminum oxide and self-assembled monolayers (SAMs). By using SAM molecules with an electro-optical functionality tuning of the photoinduced charge transfer at the interface of semiconductor and SAM upon illumination with laser light can be achieved. Control of the threshold voltage by the SAM composition enables the optical operation of the transistors without...

  6. Exciton-polaron quenching in organic thin-film transistors studied by fluorescence lifetime imaging microscopy

    DEFF Research Database (Denmark)

    Jensen, Per Baunegaard With; Leißner, Till; Osadnik, Andreas;

    Organic semiconductors show great potential in electronic and optical applications. However, a major challenge is the degradation of the semiconductor materials that cause a reduction in device performance. Here, we present our investigations of Organic Thin Film Transistors (OTFT) based on the m......Organic semiconductors show great potential in electronic and optical applications. However, a major challenge is the degradation of the semiconductor materials that cause a reduction in device performance. Here, we present our investigations of Organic Thin Film Transistors (OTFT) based...

  7. Charge transport in disordered organic field-effect transistors

    NARCIS (Netherlands)

    Tanase, C; Blom, PWM; Meijer, EJ; de Leeuw, DM; Jabbour, GE; Carter, SA; Kido, J; Lee, ST; Sariciftci, NS

    2002-01-01

    The transport properties of poly(2,5-thienylene vinylene) (PTV) field-effect transistors (FET) have been investigated as a function of temperature under controlled atmosphere. In a disordered semiconductor as PTV the charge carrier mobility, dominated by hopping between localized states, is dependen

  8. Determination of optimal ionic liquid for organic single-crystal field-effect transistors

    Science.gov (United States)

    Ono, S.; Miwa, K.; Seki, S.

    2016-02-01

    We investigate organic single-crystal field-effect transistors with various ionic liquids as gate dielectric. We find that the mobility of the field-effect transistors for both p-type and n-type organic semiconductors increases with decreasing total capacitance of the ionic liquid. However, it does not depend on the ion species at the interface between the organic semiconductor and the ionic liquid. By choosing an appropriate ionic liquid, a high carrier mobility of 12.4 cm2/V s in rubrene single crystals (p-type) and 0.13 cm2/V s in 7.7.8.8-Tetracyanoquinodimethane single crystals (n-type) are achieved. This study clarifies the influence of ionic liquids on the device performance of organic field-effect transistors and shows a way to maximize carrier mobility at the solid/liquid interface.

  9. Unidirectional coating technology for organic field-effect transistors: materials and methods

    International Nuclear Information System (INIS)

    Solution-processed organic field-effect transistors (OFETs) are essential for developing organic electronics. The encouraging development in solution-processed OFETs has attracted research interest because of their potential in low-cost devices with performance comparable to polycrystalline-silicon-based transistors. In recent years, unidirectional coating technology, featuring thin-film coating along only one direction and involving specific materials as well as solution-assisted fabrication methods, has attracted intensive interest. Transistors with organic semiconductor layers, which are deposited via unidirectional coating methods, have achieved high performance. In particular, carrier mobility has been greatly enhanced to values much higher than 10 cm2 V−1 s−1. Such significant improvement is mainly attributed to better control in morphology and molecular packing arrangement of organic thin film. In this review, typical materials that are being used in OFETs are discussed, and demonstrations of unidirectional coating methods are surveyed. (invited review)

  10. Large scale dynamos with ambipolar diffusion nonlinearity

    CERN Document Server

    Brandenburg, A; Brandenburg, Axel; Subramanian, Kandaswamy

    2000-01-01

    It is shown that ambipolar diffusion as a toy nonlinearity leads to very similar behaviour of large scale turbulent dynamos as full MHD. This is demonstrated using both direct simulations in a periodic box and a closure model for the magnetic correlation functions applicable to infinite space. Large scale fields develop via a nonlocal inverse cascade as described by the alpha-effect. However, because magnetic helicity can only change on a resistive timescale, the time it takes to organize the field into large scales increases with magnetic Reynolds number.

  11. Organic-inorganic proximity effect in the magneto-conductance of vertical organic field effect transistors

    Science.gov (United States)

    Khachatryan, B.; Greenman, M.; Devir-Wolfman, A. H.; Tessler, N.; Ehrenfreund, E.

    2016-07-01

    Vertical organic field effect transistors having a patterned source electrode and an a-SiO2 insulation layer show high performance as a switching element with high transfer characteristics. By measuring the low field magneto-conductance under ambient conditions at room temperature, we show here that the proximity of the inorganic a-SiO2 insulation to the organic conducting channel affects considerably the magnetic response. We propose that in n-type devices, electrons in the organic conducting channel and spin bearing charged defects in the inorganic a-SiO2 insulation layer (e.g., O2 = Si+.) form oppositely charged spin pairs whose singlet-triplet spin configurations are mixed through the relatively strong hyperfine field of 29Si. By increasing the contact area between the insulation layer and the conducting channel, the ˜2% magneto-conductance response may be considerably enhanced.

  12. 2D Mica Crystal as Electret in Organic Field-Effect Transistors for Multistate Memory.

    Science.gov (United States)

    Zhang, Xiaotao; He, Yudong; Li, Rongjin; Dong, Huanli; Hu, Wenping

    2016-05-01

    Organic nonvolatile multistate storage devices based on organic field-effect transistors using mica as the 2D single-crystal electrets are developed. A4-paper-sized 2D mica crystals with flat surface are prepared successfully. Devices with mica electrets exhibit a typical memory effect and show ideal output curves on both the on and the off states.

  13. Integration of silk protein in organic and light-emitting transistors.

    Science.gov (United States)

    Capelli, R; Amsden, J J; Generali, G; Toffanin, S; Benfenati, V; Muccini, M; Kaplan, D L; Omenetto, F G; Zamboni, R

    2011-07-01

    We present the integration of a natural protein into electronic and optoelectronic devices by using silk fibroin as a thin film dielectric in an organic thin film field-effect transistor (OFET) ad an organic light emitting transistor device (OLET) structures. Both n- (perylene) and p-type (thiophene) silk-based OFETs are demonstrated. The measured electrical characteristics are in agreement with high-efficiency standard organic transistors, namely charge mobility of the order of 10(-2) cm(2)/Vs and on/off ratio of 10(4). The silk-based optolectronic element is an advanced unipolar n-type OLET that yields a light emission of 100nW. PMID:22899899

  14. A flexible organic active matrix circuit fabricated using novel organic thin film transistors and organic light-emitting diodes

    KAUST Repository

    Gutiérrez-Heredia, Gerardo

    2010-10-04

    We present an active matrix circuit fabricated on plastic (polyethylene naphthalene, PEN) and glass substrates using organic thin film transistors and organic capacitors to control organic light-emitting diodes (OLEDs). The basic circuit is fabricated using two pentacene-based transistors and a capacitor using a novel aluminum oxide/parylene stack (Al2O3/ parylene) as the dielectric for both the transistor and the capacitor. We report that our circuit can deliver up to 15 μA to each OLED pixel. To achieve 200 cd m-2 of brightness a 10 μA current is needed; therefore, our approach can initially deliver 1.5× the required current to drive a single pixel. In contrast to parylene-only devices, the Al2O 3/parylene stack does not fail after stressing at a field of 1.7 MV cm-1 for >10 000 s, whereas \\'parylene only\\' devices show breakdown at approximately 1000 s. Details of the integration scheme are presented. © 2010 IOP Publishing Ltd.

  15. A flexible organic active matrix circuit fabricated using novel organic thin film transistors and organic light-emitting diodes

    Science.gov (United States)

    Gutiérrez-Heredia, G.; González, L. A.; Alshareef, H. N.; Gnade, B. E.; Quevedo-López, M.

    2010-11-01

    We present an active matrix circuit fabricated on plastic (polyethylene naphthalene, PEN) and glass substrates using organic thin film transistors and organic capacitors to control organic light-emitting diodes (OLEDs). The basic circuit is fabricated using two pentacene-based transistors and a capacitor using a novel aluminum oxide/parylene stack (Al2O3/parylene) as the dielectric for both the transistor and the capacitor. We report that our circuit can deliver up to 15 µA to each OLED pixel. To achieve 200 cd m-2 of brightness a 10 µA current is needed; therefore, our approach can initially deliver 1.5× the required current to drive a single pixel. In contrast to parylene-only devices, the Al2O3/parylene stack does not fail after stressing at a field of 1.7 MV cm-1 for >10 000 s, whereas 'parylene only' devices show breakdown at approximately 1000 s. Details of the integration scheme are presented.

  16. Ambipolar potential formation in TMX

    International Nuclear Information System (INIS)

    TMX experimental data on ambipolar potential control and on the accompanying electrostatic confinement are reported. New results on the radial dependence of the central-cell confining potential are given. Radial and axial particle losses as well as scaling of the central-cell axial confinement are discussed

  17. High mobility organic thin-film transistors based on p-p heterojunction buffer layer

    Science.gov (United States)

    Qian, Xianrui; Wang, Tong; Yan, Donghang

    2013-10-01

    The p-p heterojunction of 5, 6, 11, 12-tetraphenylnaphthacene/vanadyl phthalocyanine, which has been used as the buffer layer, is demonstrated. The highest field-effect mobility is 5.1 cm2/Vs, which is one of the highest reported for polycrystalline rubrene thin film transistors. Current versus voltage characteristics of heterojunction diodes are utilized to investigate the charge injection mechanism, revealing the factors that bring about the improvement of carrier injection and the reduction of contact resistance. These results suggest that our approach is very promising to fabricate high performance organic thin-film transistors for practical applications in organic electronics.

  18. Performance of Organic Field Effect Transistors with Self-Improved Cu/Organic Interfaces

    Institute of Scientific and Technical Information of China (English)

    HU Zi-Yang; CHENG Xiao-Man; WU Ren-Lei; WANG Zhong-Qiang; YIN Shou-Gen

    2009-01-01

    We fabricate pentacene-based organic field effect transistors (OFETs) with Cu as source and drain (S-D) electrodes.The fabricated devices stored for ten hours under ambient atmospheric conditions exhibit superior performance compared with the as-prepared devices.The field-effect mobility increases from 0.012 to 0.03 cm2 V-1 s-1,and the threshold voltage downshifts from -14 to -9 V.The on/off current ratios are close to the order of 104.The improved performance of the stored devices is attributed to the formation of thin Cu oxide at the Cu electrodes/organic interfaces.These results suggest a simple and available way to optimize device properties and to reduce fabrication cost for OFETs.

  19. A hydrogel capsule as gate dielectric in flexible organic field-effect transistors

    International Nuclear Information System (INIS)

    A jellified alginate based capsule serves as biocompatible and biodegradable electrolyte system to gate an organic field-effect transistor fabricated on a flexible substrate. Such a system allows operating thiophene based polymer transistors below 0.5 V through an electrical double layer formed across an ion-permeable polymeric electrolyte. Moreover, biological macro-molecules such as glucose-oxidase and streptavidin can enter into the gating capsules that serve also as delivery system. An enzymatic bio-reaction is shown to take place in the capsule and preliminary results on the measurement of the electronic responses promise for low-cost, low-power, flexible electronic bio-sensing applications using capsule-gated organic field-effect transistors

  20. A hydrogel capsule as gate dielectric in flexible organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Dumitru, L. M.; Manoli, K.; Magliulo, M.; Torsi, L., E-mail: luisa.torsi@uniba.it [Department of Chemistry, University of Bari “Aldo Moro”, Via Orabona 4, Bari I-70126 (Italy); Ligonzo, T. [Department of Physics, University of Bari “Aldo Moro”, Via Orabona 4, Bari I-70126 (Italy); Palazzo, G. [Department of Chemistry, University of Bari “Aldo Moro”, Via Orabona 4, Bari I-70126 (Italy); Center of Colloid and Surface Science—CSGI—Bari Unit, Via Orabona 4, Bari I-70126 (Italy)

    2015-01-01

    A jellified alginate based capsule serves as biocompatible and biodegradable electrolyte system to gate an organic field-effect transistor fabricated on a flexible substrate. Such a system allows operating thiophene based polymer transistors below 0.5 V through an electrical double layer formed across an ion-permeable polymeric electrolyte. Moreover, biological macro-molecules such as glucose-oxidase and streptavidin can enter into the gating capsules that serve also as delivery system. An enzymatic bio-reaction is shown to take place in the capsule and preliminary results on the measurement of the electronic responses promise for low-cost, low-power, flexible electronic bio-sensing applications using capsule-gated organic field-effect transistors.

  1. Unipolar organic transistor circuits made robust by dual-gate technology

    NARCIS (Netherlands)

    Myny, K.; Beenhakkers, M.J.; Aerle, N.A.J.M. van; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2011-01-01

    Dual-gate organic transistor technology is used to increase the robustness of digital circuits as illustrated by higher inverter gains and noise margins. The additional gate in the technology functions as a VT-control gate. Both zero-VGS-load and diode-load logic are investigated. The noise margin o

  2. PROBING STRESS EFFECTS IN SINGLE CRYSTAL ORGANIC TRANSISTORS BY SCANNING KELVIN PROBE MICROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Teague, L

    2010-06-11

    We report scanning Kelvin probe microscopy (SKPM) of single crystal difluoro bis(triethylsilylethynyl) anthradithiophene (diF-TESADT) organic transistors. SKPM provides a direct measurement of the intrinsic charge transport in the crystals independent of contact effects and reveals that degradation of device performance occurs over a time period of minutes as the diF-TESADT crystal becomes charged.

  3. Enhance the lifetime and bias stress reliability in organic vertical transistor by UV/Ozone treatment

    Science.gov (United States)

    Lin, Hung-Cheng; Chang, Ming-Yu; Zan, Hsiao-Wen; Meng, Hsin-Fei; Chao, Yu-Chiang

    In this paper, we use UV/Ozone treatment to improve the lifetime and bias stress reliability of organic transistor with vertical channel. Even if vertical organic transistor exhibits better bias stress reliability than organic field effect transistor (OFET) due to bulk conduction mechanism, poor lifetime performance is still a challenge. Adding octadecyltrichlorosilane (OTS) to treat the vertical channel can reduce the trapping state and hence improve the bias stress ability. However, off-current is much higher after 6 days and lifetime performance is degraded. On the other hand, after 4000-s on-state bias stress, stable output current and on/off current ratio are demonstrated by using UV/Ozone to treat vertical channels. Threshold voltage shift is only -0.02 V which is much smaller than OFET with the same organic semiconductor material. Furthermore, the output current is also an order enhanced. Nevertheless, unlike device with OTS treatment, no obvious degradation is observed for UV/Ozone treated devices even after 170 days. With UV/Ozone treatment, the output current, bias stress reliability and lifetime were all improved. It makes vertical transistor become a promising device for the further application in display technology and flexible electronics.

  4. Organic field-effect transistor-based biosensors functionalized with protein receptors

    NARCIS (Netherlands)

    Maddalena, Francesco; Kuiper, Marjon J.; Poolman, Bert; Brouwer, Frank; Hummelen, Jan C.; de Leeuw, Dagobert; Boer, Bert de; Blom, Paul W.M.

    2010-01-01

    An organic field-effect transistor with integrated proteins (Bio-FET) for sensing of sulfate ions is presented. A sulfate receptor was engineered to contain a thiol group for surface-anchoring without affecting its binding activity. The modified receptor was covalently coupled to a maleimide-functio

  5. Organic field-effect transistor-based biosensors functionalized with protein receptors

    NARCIS (Netherlands)

    Maddalena, F.; Kuiper, M.J.; Poolman, B.; Brouwer, F.; Hummelen, J.C.; Leeuw, D.M. de; Boer, B. de; Blom, P.W.M.

    2010-01-01

    An organic field-effect transistor with integrated proteins (Bio-FET) for sensing of sulfate ions is presented. A sulfate receptor was engineered to contain a thiol group for surface-anchoring without affecting its binding activity. The modified receptor was covalently coupled to a maleimide- functi

  6. DNA adsorption measured with ultra-thin film organic field effect transistors

    NARCIS (Netherlands)

    Stoliar, P.; Bystrenova, E.; Quiroga, S.D.; Annibale, P.; Facchini, M.; Spijkman, M.; Setayesh, S.; Leeuw, D. de; Biscarini, F.

    2009-01-01

    Organic ultra-thin film field effect transistors (FET) are operated as label-free sensors of deoxyribonucleic acid (DNA) adsorption. Linearized plasmid DNA molecules (4361 base pairs) are deposited froma solution on two monolayers thick pentacene FET. The amount of adsorbed DNA is measured by AFM an

  7. Organic nanofibers integrated by transfer technique in field-effect transistor devices

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob; Thilsing-Hansen, Kasper;

    2011-01-01

    The electrical properties of self-assembled organic crystalline nanofibers are studied by integrating these on field-effect transistor platforms using both top and bottom contact configurations. In the staggered geometries, where the nanofibers are sandwiched between the gate and the source...

  8. Organic thin film transistors with polymer brush gate dielectrics synthesized by atom transfer radical polymerization

    DEFF Research Database (Denmark)

    Pinto, J.C.; Whiting, G.L.; Khodabakhsh, S.;

    2008-01-01

    Low operating voltage is an important requirement that must be met for industrial adoption of organic field-effect transistors (OFETs). We report here solution fabricated polymer brush gate insulators with good uniformity, low surface roughness and high capacitance. These ultra thin polymer films...

  9. Single-crystal organic field-effect transistors based on dibenzo-tetrathiafulvalene

    NARCIS (Netherlands)

    Mas-Torrent, M.; Hadley, P.; Bromley, S.T.; Crivillers, N.; Veciana, J.; Rovira, C.

    2004-01-01

    We report on the fabrication and characterization of field-effect transistors based on single crystals of the organic semiconductor dibenzo-tetrathiafulvalene (DB-TTF). We demonstrate that it is possible to prepare very-good-quality DB-TTF crystals from solution. These devices show high field-effect

  10. Detection of saliva-range glucose concentrations using organic thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Elkington, D.; Belcher, W. J.; Dastoor, P. C.; Zhou, X. J. [Centre for Organic Electronics, University of Newcastle, Callaghan, New South Wales 2308 (Australia)

    2014-07-28

    We describe the development of a glucose sensor through direct incorporation of an enzyme (glucose oxidase) into the gate of an organic thin film transistor (OTFT). We show that glucose diffusion is the key determinant of the device response time and present a mechanism of glucose sensing in these devices that involves protonic doping of the transistor channel via enzymatic oxidation of glucose. The integrated OTFT sensor is sensitive across 4 decades of glucose concentration; a range that encompasses both the blood and salivary glucose concentration levels. As such, this work acts as a proof-of-concept for low-cost printed biosensors for salivary glucose.

  11. Field-effect transistors based on self-organized molecular nanostripes

    DEFF Research Database (Denmark)

    Cavallini, M.; Stoliare, P.; Moulin, J.-F.;

    2005-01-01

    Charge transport properties in organic semiconductors depend strongly on molecular order. Here we demonstrate field-effect transistors where drain current flows through a precisely defined array of nanostripes made of crystalline and highly ordered molecules. The molecular stripes are fabricated...... across the channel of the transistor by a stamp-assisted deposition of the molecular semiconductors from a solution. As the solvent evaporates, the capillary forces drive the solution to form menisci under the stamp protrusions. The solute precipitates only in the regions where the solution is confined...

  12. Preparation and operation characteristics of organic semiconductor transistor using thin film Al gate and copper phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The organic static induction transistors (OSITs) are fabricated by the method of evaporating and plating in a vacuum with copper phthalocyanine (CuPc) dye, and has a five layered structure of Au/CuPc/AL/CuPc/Au. The experiment reveals that OSITs have obtained a low driving voltage, high current density and high switch speed such as IDs = 1.2 × 10-6A/mm2 , and the degree of 1 000 Hz. The OSITs have excellent operation characteristics of typical static induction transistors.

  13. Detection of saliva-range glucose concentrations using organic thin-film transistors

    Science.gov (United States)

    Elkington, D.; Belcher, W. J.; Dastoor, P. C.; Zhou, X. J.

    2014-07-01

    We describe the development of a glucose sensor through direct incorporation of an enzyme (glucose oxidase) into the gate of an organic thin film transistor (OTFT). We show that glucose diffusion is the key determinant of the device response time and present a mechanism of glucose sensing in these devices that involves protonic doping of the transistor channel via enzymatic oxidation of glucose. The integrated OTFT sensor is sensitive across 4 decades of glucose concentration; a range that encompasses both the blood and salivary glucose concentration levels. As such, this work acts as a proof-of-concept for low-cost printed biosensors for salivary glucose.

  14. Study of top and bottom contact resistance in one organic field-effect transistor

    Institute of Scientific and Technical Information of China (English)

    Liu Ge; Liu Ming; Wang Hong; Shang Li-Wei; Ji Zhuo-Yu; Liu Xing-Hua; Liu Jiang

    2009-01-01

    This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated,in whic hthe top electrodes and the bottom electrodes were combined in parallel resistances within one transistor.With the facility of the novel structure,the difference of contact resistance between the top contact geometry and the bottom contact geometry was studied.The hybrid contact devices showed similar characteristics with the top contact configuration devices,which provide helpful evidence on the lower contact resistance of the top contact configuration device.The origin of the different contact resistance between the top contact device and the bottom contact device was discussed.

  15. Metal nanoparticles in organic field-effect transistor: Transition from charge trapping to conduction mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Keanchuan, E-mail: lee.kc@petronas.com.my [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Weis, Martin [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-03-03

    Self-assembled monolayers of metal nanoparticles (NPs) are envisioned for various devices and have been investigated for possible applications. However, organic envelope of NPs which is required for self-assembling must be often removed prior further device fabrication. Here, we report on effect of ozonolysis on monolayer of silver NPs (Ag NPs) with size of 8 nm and its impact on Ag NPs utilization in organic field-effect transistor. It was found that Ag NPs covered by organics serve like a traps and removal of insulating organics decreases number of traps and consequently increases Ag NPs monolayer conductivity. - Highlights: • Organic field-effect transistor (OFET) with nanoparticle (NP) film was fabricated • Electrical and optical properties of NP and OFET were studied upon UV irradiation • We report a transition from charge trapping to conduction mechanism of NPs in OFET.

  16. Metal nanoparticles in organic field-effect transistor: Transition from charge trapping to conduction mechanism

    International Nuclear Information System (INIS)

    Self-assembled monolayers of metal nanoparticles (NPs) are envisioned for various devices and have been investigated for possible applications. However, organic envelope of NPs which is required for self-assembling must be often removed prior further device fabrication. Here, we report on effect of ozonolysis on monolayer of silver NPs (Ag NPs) with size of 8 nm and its impact on Ag NPs utilization in organic field-effect transistor. It was found that Ag NPs covered by organics serve like a traps and removal of insulating organics decreases number of traps and consequently increases Ag NPs monolayer conductivity. - Highlights: • Organic field-effect transistor (OFET) with nanoparticle (NP) film was fabricated • Electrical and optical properties of NP and OFET were studied upon UV irradiation • We report a transition from charge trapping to conduction mechanism of NPs in OFET

  17. Preparation and characteristics of flexible all-organic thin-film field-effect transistor

    Institute of Scientific and Technical Information of China (English)

    QIU Yong; HU Yuanchuan; Dong Guifang; WANG Liduo; Xie Junfeng; MA Yaning

    2003-01-01

    All-organic thin-film field-effect transistor was prepared on flexible poly(ethylene-terephthalate) (PET) substrate. Poly(methyl-methacrylate) (PMMA) and pentacene are used as a dielectric layer and a semiconductor layer, respectively. The hole mobility of the transistor can reach 2.10×10-2 cm2/Vs, and the on/off current ratio was larger than 105. The performances of the transistor, when the substrate is cured under different radius, were also measured. It was found that the device performance did not change when the curly direction was vertical to the channel length direction and when the curly direction was parallel to the channel length direction with 3.67 cm curvature radius, the mobility of the device increased by more than 20% and the on/off ratio decreased more than one order.

  18. Materials and devices with applications in high-end organic transistors

    International Nuclear Information System (INIS)

    The development of functional materials typically benefits from an understanding of the microscopic mechanisms by which those materials operate. To accelerate the development of organic semiconductor devices with industrial applications in flexible and printed electronics, it is essential to elucidate the mechanisms of charge transport associated with molecular-scale charge transfer. In this study, we employed Hall effect measurements to differentiate coherent band transport from site-to-site hopping. The results of tests using several different molecular systems as the active semiconductor layers demonstrate that high-mobility charge transport in recently-developed solution-crystallized organic transistors is the result of a band-like mechanism. These materials, which have the potential to be organic transistors exhibiting the highest speeds ever obtained, are significantly different from the conventional lower-mobility organic semiconductors with incoherent hopping-like transport mechanisms which were studied in the previous century. They may be categorized as “high-end” organic semiconductors, characterized by their coherent electronic states and high values of mobility which are close to or greater than 10 cm2/Vs. - Highlights: • Transport in high-mobility solution-crystallized organic transistors is band-like. • High-end organic semiconductors carry coherent electrons with mobility > 10 cm2/Vs. • Hall-effect measurement differentiates coherent band transport from hopping. • We found an anomalous pressure effect in organic semiconductors

  19. Multifunctional Self-Assembled Monolayers for Organic Field-Effect Transistors

    Science.gov (United States)

    Cernetic, Nathan

    Organic field effect transistors (OFETs) have the potential to reach commercialization for a wide variety of applications such as active matrix display circuitry, chemical and biological sensing, radio-frequency identification devices and flexible electronics. In order to be commercially competitive with already at-market amorphous silicon devices, OFETs need to approach similar performance levels. Significant progress has been made in developing high performance organic semiconductors and dielectric materials. Additionally, a common route to improve the performance metric of OFETs is via interface modification at the critical dielectric/semiconductor and electrode/semiconductor interface which often play a significant role in charge transport properties. These metal oxide interfaces are typically modified with rationally designed multifunctional self-assembled monolayers. As means toward improving the performance metrics of OFETs, rationally designed multifunctional self-assembled monolayers are used to explore the relationship between surface energy, SAM order, and SAM dipole on OFET performance. The studies presented within are (1) development of a multifunctional SAM capable of simultaneously modifying dielectric and metal surface while maintaining compatibility with solution processed techniques (2) exploration of the relationship between SAM dipole and anchor group on graphene transistors, and (3) development of self-assembled monolayer field-effect transistor in which the traditional thick organic semiconductor is replaced by a rationally designed self-assembled monolayer semiconductor. The findings presented within represent advancement in the understanding of the influence of self-assembled monolayers on OFETs as well as progress towards rationally designed monolayer transistors.

  20. Organic thin-film transistor arrays for active-matrix organic light emitting diode

    Science.gov (United States)

    Lee, Sangyun; Moon, Hyunsik; Kim, Do H.; Koo, Bon-Won; Jeong, Eun-Jeong; Lee, Bang-Lin; Kim, Joo-Young; Lee, Eunkyung; Hahn, Kook-Min; Han, Jeong-Seok; Park, Jung-Il; Seon, Jong-Baek; Kim, Jung-Woo; Chun, Young-Tea; Kim, Sangyeol; Kang, Sung K.

    2007-09-01

    We developed an active matrix organic light-emitting diodes (AMOLEDs) on a glass using two organic thin-film transistors (OTFTs) and a capacitor in a pixel. OTFTs switching-arrays with 64 scan lines and 64 (RGB) data lines were designed and fabricated to drive OLED arrays. In this study, OTFT devices have bottom contact structures with an ink-jet printed polymer semiconductor and an organic insulator as a gate dielectric. The width and length of the switching OTFT is 500μm and 10μm, respectively and the driving OTFT has 900μm channel width with the same channel length. The characteristics of the OTFTs were examined using test cells around display area. On/off ratio, mobility, on-current of switching OTFT and on-current of driving OTFT were 10 6, 0.1 cm2/V-sec, order of 8μA and over 70 μA respectively. These properties were enough to drive the AMOLEDs over 60 Hz frame rate. AMOLEDs composed of the OTFT switching arrays and OLEDs made by deposition of small molecule materials were fabricated and driven to make moving images, successfully.

  1. Concept of rewritable organic ferroelectric random access memory in two lateral transistors-in-one cell architecture

    International Nuclear Information System (INIS)

    We propose a concept of rewritable ferroelectric random access memory (RAM) with two lateral organic transistors-in-one cell architecture. Lateral integration of a paraelectric organic field-effect transistor (OFET), being a selection transistor, and a ferroelectric OFET as a memory transistor is realized using a paraelectric depolarizing layer (PDL) which is patterned on a ferroelectric insulator by transfer-printing. For the selection transistor, the key roles of the PDL are to reduce the dipolar strength and the surface roughness of the gate insulator, leading to the low memory on–off ratio and the high switching on–off current ratio. A new driving scheme preventing the crosstalk between adjacent memory cells is also demonstrated for the rewritable operation of the ferroelectric RAM. (paper)

  2. Concept of rewritable organic ferroelectric random access memory in two lateral transistors-in-one cell architecture

    Science.gov (United States)

    Kim, Min-Hoi; Lee, Gyu Jeong; Keum, Chang-Min; Lee, Sin-Doo

    2014-02-01

    We propose a concept of rewritable ferroelectric random access memory (RAM) with two lateral organic transistors-in-one cell architecture. Lateral integration of a paraelectric organic field-effect transistor (OFET), being a selection transistor, and a ferroelectric OFET as a memory transistor is realized using a paraelectric depolarizing layer (PDL) which is patterned on a ferroelectric insulator by transfer-printing. For the selection transistor, the key roles of the PDL are to reduce the dipolar strength and the surface roughness of the gate insulator, leading to the low memory on-off ratio and the high switching on-off current ratio. A new driving scheme preventing the crosstalk between adjacent memory cells is also demonstrated for the rewritable operation of the ferroelectric RAM.

  3. Polymer brush and inorganic oxide hybrid nanodielectrics for high performance organic transistors.

    Science.gov (United States)

    Li, Liqiang; Hu, Wenping; Chi, Lifeng; Fuchs, Harald

    2010-04-29

    A novel covalence-linked PMMA-SiO(2) hybrid nanodielectrics was prepared by grafting approximately 10 nm PMMA brush onto the SiO(2) (approximately 9 nm) surface, which effectively combines the respective merits of PMMA and SiO(2). As a result, the hybrid nanodielectrics exhibit excellent dielectric performance (e.g., low leakage density (<10(-7) A/cm(2) at 6 MV/cm), high breakdown voltage (7 MV/cm), high capacitance (142 nF/cm(2)), good operational stability, and good compatibility with organic semiconductors), and enable organic field-effect transistors (OFETs) to work with high performance and low voltage. These results may open a way to build ultrathin dielectrics for high performance transistor and circuit, as well as for microelectronics, nanoelectronics, and organic electronics.

  4. Patterning technology for solution-processed organic crystal field-effect transistors

    International Nuclear Information System (INIS)

    Organic field-effect transistors (OFETs) are fundamental building blocks for various state-of-the-art electronic devices. Solution-processed organic crystals are appreciable materials for these applications because they facilitate large-scale, low-cost fabrication of devices with high performance. Patterning organic crystal transistors into well-defined geometric features is necessary to develop these crystals into practical semiconductors. This review provides an update on recent development in patterning technology for solution-processed organic crystals and their applications in field-effect transistors. Typical demonstrations are discussed and examined. In particular, our latest research progress on the spin-coating technique from mixture solutions is presented as a promising method to efficiently produce large organic semiconducting crystals on various substrates for high-performance OFETs. This solution-based process also has other excellent advantages, such as phase separation for self-assembled interfaces via one-step spin-coating, self-flattening of rough interfaces, and in situ purification that eliminates the impurity influences. Furthermore, recommendations for future perspectives are presented, and key issues for further development are discussed. (review)

  5. Organic single-crystal field-effect transistors

    NARCIS (Netherlands)

    De Boer, R.W.I.

    2005-01-01

    Organic electronics constitute an innovative field, with interesting applications complementary to the silicon semiconductor technology. From a scientific perspective, there is large interest in the fundamental understanding of electrical transport in organic semiconductors. However, a well-develope

  6. Flexible Textile-Based Organic Transistors Using Graphene/Ag Nanoparticle Electrode

    Directory of Open Access Journals (Sweden)

    Youn Kim

    2016-08-01

    Full Text Available Highly flexible and electrically-conductive multifunctional textiles are desirable for use in wearable electronic applications. In this study, we fabricated multifunctional textile composites by vacuum filtration and wet-transfer of graphene oxide films on a flexible polyethylene terephthalate (PET textile in association with embedding Ag nanoparticles (AgNPs to improve the electrical conductivity. A flexible organic transistor can be developed by direct transfer of a dielectric/semiconducting double layer on the graphene/AgNP textile composite, where the textile composite was used as both flexible substrate and conductive gate electrode. The thermal treatment of a textile-based transistor enhanced the electrical performance (mobility = 7.2 cm2·V−1·s−1, on/off current ratio = 4 × 105, and threshold voltage = −1.1 V due to the improvement of interfacial properties between the conductive textile electrode and the ion-gel dielectric layer. Furthermore, the textile transistors exhibited highly stable device performance under extended bending conditions (with a bending radius down to 3 mm and repeated tests over 1000 cycles. We believe that our simple methods for the fabrication of graphene/AgNP textile composite for use in textile-type transistors can potentially be applied to the development of flexible large-area electronic clothes.

  7. Thiophene-fused tetracene diimide with low band gap and ambipolar behavior

    KAUST Repository

    Ye, Qun

    2011-11-18

    The first tetracene diimide derivative fused with four thiophene rings, TT-TDI, was synthesized by an FeCl3 mediated oxidative cyclodehydrogenation reaction. TT-TDI exhibited a low band gap of 1.52 eV and amphoteric redox behavior. TT-TDI also showed a liquid crystalline property and ambipolar charge transport in thin film field-effect transistors. © 2011 American Chemical Society.

  8. The Integration and Applications of Organic Thin Film Transistors and Ferroelectric Polymers

    Science.gov (United States)

    Hsu, Yu-Jen

    Organic thin film transistors and ferroelectric polymer (polyvinylidene difluoride) sheet material are integrated to form various sensors for stress/strain, acoustic wave, and Infrared (heat) sensing applications. Different from silicon-based transistors, organic thin film transistors can be fabricated and processed in room-temperature and integrated with a variety of substrates. On the other hand, polyvinylidene difluoride (PVDF) exhibits ferroelectric properties that are highly useful for sensor applications. The wide frequency bandwidth (0.001 Hz to 10 GHz), vast dynamic range (100n to 10M psi), and high elastic compliance (up to 3 percent) make PVDF a more suitable candidate over ceramic piezoelectric materials for thin and flexible sensor applications. However, the low Curie temperature may have impeded its integration with silicon technology. Organic thin film transistors, however, do not have the limitation of processing temperature, hence can serve as transimpedance amplifiers to convert the charge signal generated by PVDF into current signal that are more measurable and less affected by any downstream parasitics. Piezoelectric sensors are useful for a range of applications, but passive arrays suffer from crosstalk and signal attenuation which have complicated the development of array-based PVDF sensors. We have used organic field effect transistors, which are compatible with the low Curie temperature of a flexible piezoelectric polymer,PVDF, to monolithically fabricate transimpedance amplifiers directly on the sensor surface and convert the piezoelectric charge signal into a current signal which can be detected even in the presence of parasitic capacitances. The device couples the voltage generated by the PVDF film under strain into the gate of the organic thin film transistors (OFET) using an arrangement that allows the full piezoelectric voltage to couple to the channel, while also increasing the charge retention time. A bipolar detector is created by

  9. Direct visualization and modeling of carrier distribution in organic light emitting transistor

    Energy Technology Data Exchange (ETDEWEB)

    Mashiko, Yasuhiro; Taguchi, Dai; Manaka, Takaaki [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8552 (Japan); Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo, 152-8552 (Japan); Weis, Martin [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia)

    2014-03-03

    By using microscopic electric field induced second harmonic generation (EFISHG) measurement, we studied the carrier distribution in the channel of organic light emitting transistors with an active layer of poly(9,9-di-n-octylfluorene-alt-benzothiadiazole). EFISHG signals were clearly observed in the point where the electroluminescence is generated. Results suggested that the highest enhancement of the electric field is on zero-potential position in the channel, which represents the meeting point of electrons and holes and is an origin of the electroluminescence. The transmission line model analysis of the carrier distribution of the channel supported this conclusion. - Highlights: • Carrier distribution in organic light emitting transistor channel was determined. • Second-harmonic generation images were clearly observed in the emission region. • A transmission line model well accounted for the observed carrier behavior.

  10. Performance improvement in pentacene organic thin film transistors by inserting a C60 ultrathin layer

    Institute of Scientific and Technical Information of China (English)

    Sun Qin-Jun; Xu Zheng; Zhao Su-Ling; Zhang Fu-Jun; Gao Li-Yan

    2011-01-01

    The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification,the injection harrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact of OTFTs should be carried out.

  11. Diketopyrrolopyrrole-diketopyrrolopyrrole-based conjugated copolymer for high-mobility organic field-effect transistors

    KAUST Repository

    Kanimozhi, Catherine K.

    2012-10-10

    In this communication, we report the synthesis of a novel diketopyrrolopyrrole-diketopyrrolopyrrole (DPP-DPP)-based conjugated copolymer and its application in high-mobility organic field-effect transistors. Copolymerization of DPP with DPP yields a copolymer with exceptional properties such as extended absorption characteristics (up to ∼1100 nm) and field-effect electron mobility values of >1 cm 2 V -1 s -1. The synthesis of this novel DPP-DPP copolymer in combination with the demonstration of transistors with extremely high electron mobility makes this work an important step toward a new family of DPP-DPP copolymers for application in the general area of organic optoelectronics. © 2012 American Chemical Society.

  12. Ambipolar Transport and Gate-Induced Superconductivity in Layered Transition Metal Dichalcogenides

    Science.gov (United States)

    Shi, Wu; Ye, Jianting; Zhang, Yijing; Suzuki, Ryuji; Saito, Yu; Iwasa, Yoshihiro

    2014-03-01

    Transition metal dichalcogenides (TMDs) are well known van der Waals layered materials that are easy to be exfoliated into atomically flat nano scale flakes. Owing to high efficiency of electrical double layer (EDL) dielectrics, thin flakes of TMDs have achieved high performance ambipolar transistor operation and established metallic states with high mobility, which are ideal for inducing superconductivity. Here, we report a comprehensive study of ambipolar transport behaviors in the EDL transistors (EDLTs) of MoS2, MoSe2 and MoTe2 thin flakes down to 2 K. In comparison, MoSe2 EDLT displayed a well-balanced ambipolar transistor operation while the other two showed opposite predominance in electron and hole accumulation, respectively. By modulation of carrier densities, the metal insulator transition (MIT) was observed in both electron and hole transport measurements. Particularly, superconducting transitions were reached after the formation of metallic states in the electron side. The phase diagram of transition temperature-carrier density was established and a dome-shaped structure was confirmed, revealing a universal feature of gate-induce superconductivity in layered band insulators. Present address: University of Groningen.

  13. Monolithically integrated, flexible display of polymer-dispersed liquid crystal driven by rubber-stamped organic thin-film transistors

    International Nuclear Information System (INIS)

    This letter describes the monolithic integration of rubber-stamped thin-film organic transistors with polymer-dispersed liquid crystals (PDLCs) to create a multipixel, flexible display with plastic substrates. We report the electro-optic switching behavior of the PDLCs as driven by the organic transistors, and we show that our displays operate robustly under flexing and have a contrast comparable to that of newsprint. [copyright] 2001 American Institute of Physics

  14. Printable Biosensors based on Organic Electrochemical Transistors with a Platinized Gate Electrode

    OpenAIRE

    Broman, Eva

    2012-01-01

    There is a great demand for low-cost disposable sensors in a variety of markets, such as the food chainand health care. No assay is performed more than that of glucose and approximately 85 % of the entirebiosensor market accounts for glucose biosensors. Each year, 6 billion glucose assays are performed andthe majority of them are based on electrochemical detection. Organic electrochemical transistors(OECTs) have favorable properties in terms of low operating voltages and have previously been ...

  15. An ion sensitive organic field-effect transistor incorporating the ionophore valinomycin.

    OpenAIRE

    Ritjareonwattu, S.; Yun, Y.; Pearson, C.; Petty, M.C.

    2012-01-01

    We report on the effect of depositing the ionophore valinomycin onto the polymethylmethacrylate (PMMA) gate insulator of an ion-sensitive organic field-effect transistor (ISOFET) based on poly(3-hexylthiophene). The ionophore was deposited onto the PMMA using the Langmuir-Blodgett (LB) technique; thin films based on pure valinomycin and those in which valinomycin was mixed with arachidic acid were investigated. The pH sensitivity of the reference ISOFET could be improved significantly when th...

  16. Fabrication of pentacene organic field-effect transistors with polyimide gate dielectric layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The organic field effect transistors had been fabricated using the pentacene by vacuum evaporation as the active layer, the polyimide by spin coating as insulator layer, and aluminum by vacuum evaporation as gate, source and drain electrodes respectively. The field-effect mobility of 0.079 cm2/V.s was tested at Vds=70 V, and on/off radio up to 1.7×104.

  17. Improved sensor selectivity for chemical vapors using organic thin-film transistors

    OpenAIRE

    Royer, James Edward

    2012-01-01

    Organic thin-film transistors (OTFTs) offer unique methods for chemical vapor detection due to multiple device parameters which are influenced by reactive gases. The simplest conventional readout for OTFT sensors is the drain current; however, the drain current is dependent on changes in fundamental device characteristics such as mobility and/or threshold voltage. The chemical properties of the analyte determine whether the mobility or threshold voltage response is dominant for the OTFT. The ...

  18. Nonlinear Transport in Organic Thin Film Transistors with Soluble Small Molecule Semiconductor.

    Science.gov (United States)

    Kim, Hyeok; Song, Dong-Seok; Kwon, Jin-Hyuk; Jung, Ji-Hoon; Kim, Do-Kyung; Kim, SeonMin; Kang, In Man; Park, Jonghoo; Tae, Heung-Sik; Battaglini, Nicolas; Lang, Philippe; Horowitz, Gilles; Bae, Jin-Hyuk

    2016-03-01

    Nonlinear transport is intensively explained through Poole-Frenkel (PF) transport mechanism in organic thin film transistors with solution-processed small molecules, which is, 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene. We outline a detailed electrical study that identifies the source to drain field dependent mobility. Devices with diverse channel lengths enable the extensive exhibition of field dependent mobility due to thermal activation of carriers among traps. PMID:27455707

  19. A Strained Organic Field-Effect-Transistor with a Gate-Tunable Superconducting Channel

    OpenAIRE

    Yamamoto, Hiroshi M.; Nakano, Masaki; Suda, Masayuki; Iwasa, Yoshihiro; Kawasaki, Masashi; Kato, Reizo

    2013-01-01

    In state-of-the-art silicon devices, mobility of the carrier is enhanced by the lattice strain from the back substrate. Such an extra control of device performance is significant in realizing high performance computing and should be valid for electric-field-induced superconducting devices, too. However, so far, the carrier density is the sole parameter for field-induced superconducting interfaces. Here we show an active organic superconducting field-effect-transistor whose lattice is modulate...

  20. Nonlinear Transport in Organic Thin Film Transistors with Soluble Small Molecule Semiconductor.

    Science.gov (United States)

    Kim, Hyeok; Song, Dong-Seok; Kwon, Jin-Hyuk; Jung, Ji-Hoon; Kim, Do-Kyung; Kim, SeonMin; Kang, In Man; Park, Jonghoo; Tae, Heung-Sik; Battaglini, Nicolas; Lang, Philippe; Horowitz, Gilles; Bae, Jin-Hyuk

    2016-03-01

    Nonlinear transport is intensively explained through Poole-Frenkel (PF) transport mechanism in organic thin film transistors with solution-processed small molecules, which is, 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene. We outline a detailed electrical study that identifies the source to drain field dependent mobility. Devices with diverse channel lengths enable the extensive exhibition of field dependent mobility due to thermal activation of carriers among traps.

  1. An organic transistor-based system for reference-less electrophysiological monitoring of excitable cells

    Science.gov (United States)

    Spanu, A.; Lai, S.; Cosseddu, P.; Tedesco, M.; Martinoia, S.; Bonfiglio, A.

    2015-03-01

    In the last four decades, substantial advances have been done in the understanding of the electrical behavior of excitable cells. From the introduction in the early 70's of the Ion Sensitive Field Effect Transistor (ISFET), a lot of effort has been put in the development of more and more performing transistor-based devices to reliably interface electrogenic cells such as, for example, cardiac myocytes and neurons. However, depending on the type of application, the electronic devices used to this aim face several problems like the intrinsic rigidity of the materials (associated with foreign body rejection reactions), lack of transparency and the presence of a reference electrode. Here, an innovative system based on a novel kind of organic thin film transistor (OTFT), called organic charge modulated FET (OCMFET), is proposed as a flexible, transparent, reference-less transducer of the electrical activity of electrogenic cells. The exploitation of organic electronics in interfacing the living matters will open up new perspectives in the electrophysiological field allowing us to head toward a modern era of flexible, reference-less, and low cost probes with high-spatial and high-temporal resolution for a new generation of in-vitro and in-vivo monitoring platforms.

  2. High-Resolution ac Measurements of the Hall Effect in Organic Field-Effect Transistors

    Science.gov (United States)

    Chen, Y.; Yi, H. T.; Podzorov, V.

    2016-03-01

    We describe a high resolving power technique for Hall-effect measurements, efficient in determining Hall mobility and carrier density in organic field-effect transistors and other low-mobility systems. We utilize a small low-frequency ac magnetic field (BrmsHall voltage, with the necessary corrections for Faraday induction. This method significantly enhances the signal-to-noise ratio and eliminates the necessity of using high magnetic fields in Hall-effect studies. With the help of this method, we are able to obtain the Hall mobility and carrier density in organic transistors with a mobility as low as μ ˜0.3 cm2 V-1 s-1 by using a compact desktop apparatus and low magnetic fields. We find a good agreement between Hall-effect and electric-field-effect measurements, indicating that, contrary to the common belief, certain organic semiconductors with mobilities below 1 cm2 V-1 s-1 can still exhibit a fully developed, band-semiconductor-like Hall effect, with the Hall mobility and carrier density matching those obtained in longitudinal transistor measurements. This suggests that, even when μ Hall-effect studies in a wide range of low-mobility materials and devices, where it is typically very difficult to resolve the Hall effect even in very high dc magnetic fields.

  3. Ion sensors based on novel fiber organic electrochemical transistors for lead ion detection.

    Science.gov (United States)

    Wang, Yuedan; Zhou, Zhou; Qing, Xing; Zhong, Weibing; Liu, Qiongzhen; Wang, Wenwen; Li, Mufang; Liu, Ke; Wang, Dong

    2016-08-01

    Fiber organic electrochemical transistors (FECTs) based on polypyrrole and nanofibers have been prepared for the first time. FECTs exhibited excellent electrical performances, on/off ratios up to 10(4) and low applied voltages below 2 V. The ion sensitivity behavior of the fiber organic electrochemical transistors was investigated. It exhibited that the transfer curve of FECTs shifted to lower gate voltage with increasing cations concentration, the sensitivity reached to 446 μA/dec in the 10(-5)-10(-2) M Pb(2+) concentration range. The ion selective properties of the FECTs have also been systematically studied for the detection of potassium, calcium, aluminum, and lead ions. The devices with different cations showed great difference in response curves. It was suitable for selectively monitoring Pb(2+) with respect to other cations. The results indicated FECTs were very effective for electrochemical sensing of lead ion, which opened a promising perspective for wearable electronics in healthcare and biological application. Graphical Abstract The schematic diagram of fiber organic electrochemical transistors based on polypyrrole and nanofibers for ion sensing. PMID:27342794

  4. Organic nanodielectrics for low voltage carbon nanotube thin film transistors and complementary logic gates.

    Science.gov (United States)

    Hur, Seung-Hyun; Yoon, Myung-Han; Gaur, Anshu; Shim, Moonsub; Facchetti, Antonio; Marks, Tobin J; Rogers, John A

    2005-10-12

    We report the implementation of three dimensionally cross-linked, organic nanodielectric multilayers as ultrathin gate dielectrics for a type of thin film transistor device that uses networks of single-walled carbon nanotubes as effective semiconductor thin films. Unipolar n- and p-channel devices are demonstrated by use of polymer coatings to control the behavior of the networks. Monolithically integrating these devices yields complementary logic gates. The organic multilayers provide exceptionally good gate dielectrics for these systems and allow for low voltage, low hysteresis operation. The excellent performance characteristics suggest that organic dielectrics of this general type could provide a promising path to SWNT-based thin film electronics.

  5. Organic single crystals or crystalline micro/nanostructures: Preparation and field-effect transistor applications

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Organic single crystals hold great promise for the development of organic semiconductor materials,because they could reveal the intrinsic electronic properties of these materials,providing high-performance electronic devices and probing the structureproperty relationships.This article reviews the preparation methods for organic single crystals or crystalline micro/nanostructures,including vapor phase growth methods and solution-processed methods,and summarizes a few methods employed in the fabrication of field-effect transistors along with dozens of examples concerning both small molecules and polymers with high field-effect performance.

  6. The design and synthesis of fused thiophenes and their applications in organic field-effect transistors

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Fused thiophenes refer to oligothienoacenes in which several thiophenes are coupled together via twoor multi-positions and their derivatives. The synthesized organic semiconductors based on fused thiophenes exhibit excellent field effect properties due to their efficient intermolecular S…S interactions and π…π stacking. The performances of organic field-effect transistors (OFETs) depend not only on the materials but also on the devices. Such factors which influence the device performances as device structures, fabrication technologies and interface engineering are extensively investigated based on the fused thiophenes. Searching for new organic semiconductors and improving the device fabrication technologies are two major issues in the development of OFETs.

  7. An Organic Nanoparticle Transistor Behaving as a Biological Spiking Synapse

    OpenAIRE

    Alibart, F.; Pleutin, S.; Guerin, D.; Novembre, C.; Lenfant, S.; Lmimouni, K.; Gamrat, C.; Vuillaume, D.

    2010-01-01

    Molecule-based devices are envisioned to complement silicon devices by providing new functions or already existing functions at a simpler process level and at a lower cost by virtue of their self-organization capabilities. Moreover, they are not bound to von Neuman architecture and this feature may open the way to other architectural paradigms. Neuromorphic electronics is one of them. Here we demonstrate a device made of molecules and nanoparticles, a nanoparticle organic memory filed-effect ...

  8. Self-Aligned Metal Electrodes in Fully Roll-to-Roll Processed Organic Transistors

    Directory of Open Access Journals (Sweden)

    Marja Vilkman

    2016-01-01

    Full Text Available We demonstrate the production of organic bottom gate transistors with self-aligned electrodes, using only continuous roll-to-roll (R2R techniques. The self-alignment allows accurate <5 µm layer-to-layer registration, which is usually a challenge in high-speed R2R environments as the standard registration methods are limited to the millimeter range—or, at best, to tens of µm if online cameras and automatic web control are utilized. The improved registration enables minimizing the overlap between the source/drain electrodes and the gate electrode, which is essential for minimizing the parasitic capacitance. The complete process is a combination of several techniques, including evaporation, reverse gravure, flexography, lift-off, UV exposure and development methods—all transferred to a continuous R2R pilot line. Altogether, approximately 80 meters of devices consisting of thousands of transistors were manufactured in a roll-to-roll fashion. Finally, a cost analysis is presented in order to ascertain the main costs and to predict whether the process would be feasible for the industrial production of organic transistors.

  9. High capacitance organic field-effect transistors with modified gate insulator surface

    Science.gov (United States)

    Majewski, L. A.; Schroeder, R.; Grell, M.; Glarvey, P. A.; Turner, M. L.

    2004-11-01

    In this paper, we report on flexible, high capacitance, pentacene, and regioregular poly(3-hexylthiophene) (rr-P3HT) organic field-effect transistors fabricated on metallized Mylar films. The gate insulator, Al2O3, was prepared by means of anodization. We show that covering the anodized gate insulator with an octadecyltrichlorosilane self-assembled monolayer or apoly(α-methylstyrene) capping layer has the same effect on carrier mobility as for thermally grown silicon oxide. In addition, temperature-dependent measurements of mobility were performed on transistors fabricated with and without modification of the gate dielectric. In the case of both the pentacene and the rr-P3HT transistors, the μ(T ) behavior shows that the cause of the mobility enhancement through surface modification is not a reduction in the level of energetic disorder (σ in Bässler's model), as in the case of the fully amorphous organic semiconductor poly(triarylamine) [Veres et al., Adv. Funct. Mater. 13, 199 (2003)]. It appears that the surface modification improves mobility by changing the morphology of the semiconducting films.

  10. Studies on different configurations of cobalt phthalocyanine based flexible organic field effect transistor

    Science.gov (United States)

    Kumar, A.; Jha, P.; Samanta, S.; Singh, A.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K.

    2016-05-01

    Organic Field Effect Transistors (OFETs) are being investigated for a number of low-cost, large area applications; particularly those that are compatible with flexible plastic substrates. Development of low temperature processes can make way for OFETs to be integrated on flexible plastic substrates. Here we have made systematic studies on OFETs in different configurations wherein we have chosen Cobalt Phthalocyanine (CoPc) as active material. We have found the best mobility (1.86 × 10-5 cm2/V-s) in Bottom Gate Top Contact configuration. However, threshold voltage (-5V) and On off ratio (62)were found to be better in Top Gate Bottom Contact configuration The electromechanical properties of the Bottom Gate Top Contact transistors were studied by measuring the transfer characteristics of the devices in bend condition and thereby calculating mobility under different radii of bending. No significant change in the mobility of the device was observed under bent conditions.

  11. Solution-processed hybrid organic-inorganic complementary thin-film transistor inverter

    Science.gov (United States)

    Cheong, Heajeong; Kuribara, Kazunori; Ogura, Shintaro; Fukuda, Nobuko; Yoshida, Manabu; Ushijima, Hirobumi; Uemura, Sei

    2016-04-01

    We investigated hybrid organic-inorganic complementary inverters with a solution-processed indium-gallium-zinc-oxide (IGZO) n-channel thin-film transistor (TFT) and p-channel TFTs using the high-uniformity polymer poly[2,5-bis(alkyl)pyrrolo[3,4-c]pyrrolo-1,4(2H,5H)-dione-alt-5,5-di(thiophene-2-yl)-2,2-(E)-2-(2-(thiophen-2-yl)vinyl)thiophene] (PDVT-10). The IGZO TFT was fabricated at 150 °C for 1 min. It showed a high field-effect mobility of 0.9 cm2·V-1·s-1 and a high on/off current ratio of 107. A hybrid complementary inverter was fabricated by combining IGZO with a PDVT-10 thin-film transistor and its operation was confirmed.

  12. Solution-Processed Organic Thin-Film Transistor Array for Active-Matrix Organic Light-Emitting Diode

    Science.gov (United States)

    Harada, Chihiro; Hata, Takuya; Chuman, Takashi; Ishizuka, Shinichi; Yoshizawa, Atsushi

    2013-05-01

    We developed a 3-in. organic thin-film transistor (OTFT) array with an ink-jetted organic semiconductor. All layers except electrodes were fabricated by solution processes. The OTFT performed well without hysteresis, and the field-effect mobility in the saturation region was 0.45 cm2 V-1 s-1, the threshold voltage was 3.3 V, and the on/off current ratio was more than 106. We demonstrated a 3-in. active-matrix organic light-emitting diode (AMOLED) display driven by the OTFT array. The display could provide clear moving images. The peak luminance of the display was 170 cd/m2.

  13. Effect of Electron-Beam Irradiation on Organic Semiconductor and Its Application for Transistor-Based Dosimeters.

    Science.gov (United States)

    Kim, Jae Joon; Ha, Jun Mok; Lee, Hyeok Moo; Raza, Hamid Saeed; Park, Ji Won; Cho, Sung Oh

    2016-08-01

    The effects of electron-beam irradiation on the organic semiconductor rubrene and its application as a dosimeter was investigated. Through the measurements of photoluminescence and the ultraviolet photoelectron spectroscopy, we found that electron-beam irradiation induces n-doping of rubrene. Additionally, we fabricated rubrene thin-film transistors with pristine and irradiated rubrene, and discovered that the decrease in transistor properties originated from the irradiation of rubrene and that the threshold voltages are shifted to the opposite directions as the irradiated layers. Finally, a highly sensitive and air-stable electron dosimeter was fabricated based on a rubrene transistor. PMID:27399874

  14. Integrated Materials Design of Organic Semiconductors for Field-Effect Transistors

    KAUST Repository

    Mei, Jianguo

    2013-05-08

    The past couple of years have witnessed a remarkable burst in the development of organic field-effect transistors (OFETs), with a number of organic semiconductors surpassing the benchmark mobility of 10 cm2/(V s). In this perspective, we highlight some of the major milestones along the way to provide a historical view of OFET development, introduce the integrated molecular design concepts and process engineering approaches that lead to the current success, and identify the challenges ahead to make OFETs applicable in real applications. © 2013 American Chemical Society.

  15. Detection of glutamate and acetylcholine with organic electrochemical transistors based on conducting polymer/platinum nanoparticle composites.

    Science.gov (United States)

    Kergoat, Loïg; Piro, Benoît; Simon, Daniel T; Pham, Minh-Chau; Noël, Vincent; Berggren, Magnus

    2014-08-27

    The aim of the study is to open a new scope for organic electrochemical transistors based on PEDOT:PSS, a material blend known for its stability and reliability. These devices can leverage molecular electrocatalysis by incorporating small amounts of nano-catalyst during the transistor manufacturing (spin coating). This methodology is very simple to implement using the know-how of nanochemistry and results in efficient enzymatic activity transduction, in this case utilizing choline oxidase and glutamate oxidase.

  16. Thickness dependence of surface morphology and charge carrier mobility in organic field-effect transistors

    International Nuclear Information System (INIS)

    With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit. (cross-disciplinary physics and related areas of science and technology)

  17. Mobility overestimation due to gated contacts in organic field-effect transistors

    Science.gov (United States)

    Bittle, Emily G.; Basham, James I.; Jackson, Thomas N.; Jurchescu, Oana D.; Gundlach, David J.

    2016-03-01

    Parameters used to describe the electrical properties of organic field-effect transistors, such as mobility and threshold voltage, are commonly extracted from measured current-voltage characteristics and interpreted by using the classical metal oxide-semiconductor field-effect transistor model. However, in recent reports of devices with ultra-high mobility (>40 cm2 V-1 s-1), the device characteristics deviate from this idealized model and show an abrupt turn-on in the drain current when measured as a function of gate voltage. In order to investigate this phenomenon, here we report on single crystal rubrene transistors intentionally fabricated to exhibit an abrupt turn-on. We disentangle the channel properties from the contact resistance by using impedance spectroscopy and show that the current in such devices is governed by a gate bias dependence of the contact resistance. As a result, extracted mobility values from d.c. current-voltage characterization are overestimated by one order of magnitude or more.

  18. Low dielectric constant-based organic field-effect transistors and metal-insulator-semiconductor capacitors

    Science.gov (United States)

    Ukah, Ndubuisi Benjamin

    This thesis describes a study of PFB and pentacene-based organic field-effect transistors (OFET) and metal-insulator-semiconductor (MIS) capacitors with low dielectric constant (k) poly(methyl methacrylate) (PMMA), poly(4-vinyl phenol) (PVP) and cross-linked PVP (c-PVP) gate dielectrics. A physical method -- matrix assisted pulsed laser evaporation (MAPLE) -- of fabricating all-polymer field-effect transistors and MIS capacitors that circumvents inherent polymer dissolution and solvent-selectivity problems, is demonstrated. Pentacene-based OFETs incorporating PMMA and PVP gate dielectrics usually have high operating voltages related to the thickness of the dielectric layer. Reduced PMMA layer thickness (≤ 70 nm) was obtained by dissolving the PMMA in propylene carbonate (PC). The resulting pentacene-based transistors exhibited very low operating voltage (below -3 V), minimal hysteresis in their transfer characteristics, and decent electrical performance. Also low voltage (within -2 V) operation using thin (≤ 80 nm) low-k and hydrophilic PVP and c-PVP dielectric layers obtained via dissolution in high dipole moment and high-k solvents -- PC and dimethyl sulfoxide (DMSO), is demonstrated to be a robust means of achieving improved electrical characteristics and high operational stability in OFETs incorporating PVP and c-PVP dielectrics.

  19. Processing and performance of organic insulators as a gate layer in organic thin film transistors fabricated on polyethylene terephthalate substrate

    Indian Academy of Sciences (India)

    Saumen Mandal; Monica Katiyar

    2013-08-01

    Fabrication of organic thin film transistor (OTFT) on flexible substrates is a challenge, because of its low softening temperature, high roughness and flexible nature. Although several organic dielectrics have been used as gate insulator, it is difficult to choose one in absence of a comparative study covering processing of dielectric layer on polyethylene terephthalate (PET), characterization of dielectric property, pentacene film morphology and OTFT characterization. Here, we present the processing and performance of three organic dielectrics, poly(4-vinylphenol) (PVPh), polyvinyl alcohol (PVA) and poly(methylmethacrylate) (PMMA), as a gate layer in pentacene-based organic thin film transistor on PET substrate. We have used thermogravimetric analysis of organic dielectric solution to determine annealing temperature for spin-coated films of these dielectrics. Comparison of the leakage currents for the three dielectrics shows PVA exhibiting lowest leakage (in the voltage range of −30 to +30 V). This is partly because solvent is completely eliminated in the case of PVA as observed by differential thermogravimetric analysis (DTGA). We propose that DTGA can be a useful tool to optimize processing of dielectric layers. From organic thin film transistor point of view, crystal structure, morphology and surface roughness of pentacene film on all the dielectric layers were studied using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM).We observe pyramidal pentacene on PVPh whereas commonly observed dendritic pentacene on PMMA and PVA surface. Pentacene morphology development is discussed in terms of surface roughness, surface energy and molecular nature of the dielectric layer.

  20. Organic Semiconductors and Nanodielectrics for Flexible, Low Voltage Thin-Film Transistors

    Science.gov (United States)

    Marks, Tobin

    2006-03-01

    Molecular materials scientists are skilled at designing and constructing individual molecules with the goal of imbuing them with predetermined chemical and physical properties. However, the subsequent task of rationally assembling them into organized, functional supramolecular architectures with precise, nanometer-level control of bulk opt-electronic properties presents another level of challenge. In this lecture, synthetic and computational approaches to addressing such problems are described in which the ultimate goal is the fabrication of flexible electronic circuits employing unconventional materials classes and unconventional fabrication techniques. The issues here concern not only the rational design, realization, and understanding of high-mobility p- and n-type organic semiconductors, but also robust enabling nanoscopic gate dielectrics having ultra-high capacitance, low leakage, and high breakdown fields. In the former area, routes to and properties of, new high-mobility heterocyclic materials are described. These materials are then used to fabricate high-performance organic thin film transistors and CMOS circuits. In the latter topic, the design, synthesis, and characterization of new high-k nanoscopic gate dielectrics are described. It is then shown how these dielectrics can be employed to significantly enhance the performance of thin-film transistors and other devices fabricated from a wide variety of both organic as well as inorganic semiconductors.

  1. Free-Standing Organic Transistors and Circuits with Sub-Micron Thicknesses

    Science.gov (United States)

    Fukuda, Kenjiro; Sekine, Tomohito; Shiwaku, Rei; Morimoto, Takuya; Kumaki, Daisuke; Tokito, Shizuo

    2016-06-01

    The realization of wearable electronic devices with extremely thin and flexible form factors has been a major technological challenge. While substrates typically limit the thickness of thin-film electronic devices, they are usually necessary for their fabrication and functionality. Here we report on ultra-thin organic transistors and integrated circuits using device components whose substrates that have been removed. The fabricated organic circuits with total device thicknesses down to 350 nm have electrical performance levels close to those fabricated on conventional flexible substrates. Moreover, they exhibit excellent mechanical robustness, whereby their static and dynamic electrical characteristics do not change even under 50% compressive strain. Tests using systematically applied compressive strains reveal that these free-standing organic transistors possess anisotropic mechanical stability, and a strain model for a multilayer stack can be used to describe the strain in this sort of ultra-thin device. These results show the feasibility of ultimate-thin organic electronic devices using free-standing constructions.

  2. Orthogonal Ambipolar Semiconductor Nanostructures for Complementary Logic Gates.

    Science.gov (United States)

    Huang, Weiguo; Markwart, Jens C; Briseno, Alejandro L; Hayward, Ryan C

    2016-09-27

    We report orthogonal ambipolar semiconductors that exhibit hole and electron transport in perpendicular directions based on aligned films of nanocrystalline "shish-kebabs" containing poly(3-hexylthiophene) (P3HT) and N,N'-di-n-octyl-3,4,9,10-perylenetetracarboxylic diimide (PDI) as p- and n-type components, respectively. Polarized optical microscopy, scanning electron microscopy, and X-ray diffraction measurements reveal a high degree of in-plane alignment. Relying on the orientation of interdigitated electrodes to enable efficient charge transport from either the respective p- or n-channel materials, we demonstrate semiconductor films with high anisotropy in the sign of charge carriers. Films of these aligned crystalline semiconductors were used to fabricate complementary inverter devices, which exhibited good switching behavior and a high noise margin of 80% of 1/2 Vdd. Moreover, complementary "NAND" and "NOR" logic gates were fabricated and found to exhibit excellent voltage transfer characteristics and low static power consumption. The ability to optimize the performance of these devices, simply by adjusting the solution concentrations of P3HT and PDI, makes this a simple and versatile method for preparing ambipolar organic semiconductor devices and high-performance logic gates. Further, we demonstrate that this method can also be applied to mixtures of PDI with another conjugated polymer, poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]) (PBTTT), with better hole transport characteristics than P3HT, opening the door to orthogonal ambipolar semiconductors with higher performance.

  3. Efficient and Hysteresis-Free Field Effect Modulation of Ambipolarly Doped Vanadium Dioxide Nanowires

    Science.gov (United States)

    Peng, Xingyue; Yang, Yiming; Hou, Yasen; Travaglini, Henry C.; Hellwig, Luke; Hihath, Sahar; van Benthem, Klaus; Lee, Kathleen; Liu, Weifeng; Yu, Dong

    2016-05-01

    The subpicosecond metal-insulator phase transition in vanadium dioxide (VO2 ) has attracted extensive attention with potential applications in ultrafast Mott transistors, which are based on electric-field-induced phase transition. However, the development of VO2 -based transistors lags behind, owing to inefficient and hysteretic gate modulation. Here we report ambipolar doping and strong field effects free of hysteresis in single-crystal VO2 nanowires synthesized via catalyst-free chemical vapor deposition. The ambipolarly doped VO2 nanowires are achieved by controlling the oxygen vacancy density during the synthesis and show strong gate effects because of their relatively low doping level. Both the doping type of the nanowires and the band-bending direction at the metal-insulator domain walls are reversibly switched by electrochemical gating, as revealed by scanning photocurrent microscopy. Furthermore, we eliminate the hysteresis in gate sweep via a hybrid gating method, which combines the merits of liquid-ionic and solid gating. The capability of efficient field effect modulation of ambipolar conduction and band alignment offers opportunities on understanding the phase transition mechanism and enables electronic applications based on VO2 .

  4. Current saturation and Coulomb interactions in organic single-crystal transistors

    Energy Technology Data Exchange (ETDEWEB)

    Fratini, S [Institut Neel-CNRS and Universite Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Xie, H; Hulea, I N; Morpurgo, A F [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Ciuchi, S [INFM-SMC, CNISM and Dipartimento di Fisica, Universita dell' Aquila, via Vetoio, I-67010 Coppito-L' Aquila (Italy)], E-mail: simone.fratini@grenoble.cnrs.fr

    2008-03-15

    Electronic transport through rubrene single-crystal field-effect transistors (FETs) is investigated experimentally in the high carrier density regime (n{approx_equal}0.1 carrier molecule{sup -1}). In this regime, we find that the current does not increase linearly with the density of charge carriers, and tends to saturate. At the same time, the activation energy for transport unexpectedly increases with increasing n. We perform a theoretical analysis in terms of a well-defined microscopic model for interacting Froehlich polarons, which quantitatively accounts for our experimental observations. This work is particularly significant for our understanding of electronic transport through organic FETs.

  5. A better understanding of organic electrochemical transistors for biosensing applications (Presentation Recording)

    Science.gov (United States)

    Friedlein, Jacob T.; Malliaras, George G.; Shaheen, Sean E.; McLeod, Robert R.

    2015-10-01

    Due to their biocompatibility, high transconductance, and low operating voltages, organic electrochemical transistors (OECTs) are promising platforms for biosensing applications. They have been used for measuring enzymes such as glucose and lactate, detecting disruptions of epithelial cell integrity, and amplifying epileptic voltage signals in rat brains. Accelerating the development of OECTs in this diverse range of potential applications, and those unforeseen, requires continued investigation of the device physics and material properties. In this presentation, we will describe our work to better understand OECT behavior, and we will discuss how this understanding can be used to develop more effective biosensors.

  6. All solution processed organic thin film transistor-backplane with printing technology for electrophoretic display

    Science.gov (United States)

    Lee, Myung W.; Song, C.K.

    2012-01-01

    In this study, solution processes were developed for backplane using an organic thin film transistor (OTFT) as a driving device for an electrophoretic display (EPD) panel. The processes covered not only the key device of OTFTs but also interlayer and pixel electrodes. The various materials and printing processes were adopted to achieve the requirements of devices and functioning layers. The performance of OTFT of the backplane was sufficient to drive EPD sheet by producing a mobility of 0.12 cm2/v x sec and on/off current ratio of 10(5).

  7. Demonstration of high current carbon nanotube enabled vertical organic field effect transistors at industrially relevant voltages

    Science.gov (United States)

    McCarthy, Mitchell

    The display market is presently dominated by the active matrix liquid crystal display (LCD). However, the active matrix organic light emitting diode (AMOLED) display is argued to become the successor to the LCD, and is already beginning its way into the market, mainly in small size displays. But, for AMOLED technology to become comparable in market share to LCD, larger size displays must become available at a competitive price with their LCD counterparts. A major issue preventing low-cost large AMOLED displays is the thin-film transistor (TFT) technology. Unlike the voltage driven LCD, the OLEDs in the AMOLED display are current driven. Because of this, the mature amorphous silicon TFT backplane technology used in the LCD must be upgraded to a material possessing a higher mobility. Polycrystalline silicon and transparent oxide TFT technologies are being considered to fill this need. But these technologies bring with them significant manufacturing complexity and cost concerns. Carbon nanotube enabled vertical organic field effect transistors (CN-VFETs) offer a unique solution to this problem (now known as the AMOLED backplane problem). The CN-VFET allows the use of organic semiconductors to be used for the semiconductor layer. Organics are known for their low-cost large area processing compatibility. Although the mobility of the best organics is only comparable to that of amorphous silicon, the CN-VFET makes up for this by orienting the channel vertically, as opposed to horizontally (like in conventional TFTs). This allows the CN-VFET to achieve sub-micron channel lengths without expensive high resolution patterning. Additionally, because the CN-VFET can be easily converted into a light emitting transistor (called the carbon nanotube enabled vertical organic light emitting transistor---CN-VOLET) by essentially stacking an OLED on top of the CN-VFET, more potential benefits can be realized. These potential benefits include, increased aperture ratio, increased OLED

  8. Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville

    2011-01-01

    Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

  9. Flexible All-organic, All-solution Processed Thin Film Transistor Array with Ultrashort Channel

    Science.gov (United States)

    Xu, Wei; Hu, Zhanhao; Liu, Huimin; Lan, Linfeng; Peng, Junbiao; Wang, Jian; Cao, Yong

    2016-07-01

    Shrinking the device dimension has long been the pursuit of the semiconductor industry to increase the device density and operation speed. In the application of thin film transistors (TFTs), all-organic TFT arrays made by all-solution process are desired for low cost and flexible electronics. One of the greatest challenges is how to achieve ultrashort channel through a cost-effective method. In our study, ultrashort-channel devices are demonstrated by direct inkjet printing conducting polymer as source/drain and gate electrodes without any complicated substrate’s pre-patterning process. By modifying the substrate’s wettability, the conducting polymer’s contact line is pinned during drying process which makes the channel length well-controlled. An organic TFT array of 200 devices with 2 μm channel length is fabricated on flexible substrate through all-solution process. The simple and scalable process to fabricate high resolution organic transistor array offers a low cost approach in the development of flexible and wearable electronics.

  10. Flexible All-organic, All-solution Processed Thin Film Transistor Array with Ultrashort Channel.

    Science.gov (United States)

    Xu, Wei; Hu, Zhanhao; Liu, Huimin; Lan, Linfeng; Peng, Junbiao; Wang, Jian; Cao, Yong

    2016-01-01

    Shrinking the device dimension has long been the pursuit of the semiconductor industry to increase the device density and operation speed. In the application of thin film transistors (TFTs), all-organic TFT arrays made by all-solution process are desired for low cost and flexible electronics. One of the greatest challenges is how to achieve ultrashort channel through a cost-effective method. In our study, ultrashort-channel devices are demonstrated by direct inkjet printing conducting polymer as source/drain and gate electrodes without any complicated substrate's pre-patterning process. By modifying the substrate's wettability, the conducting polymer's contact line is pinned during drying process which makes the channel length well-controlled. An organic TFT array of 200 devices with 2 μm channel length is fabricated on flexible substrate through all-solution process. The simple and scalable process to fabricate high resolution organic transistor array offers a low cost approach in the development of flexible and wearable electronics. PMID:27378163

  11. X-ray imager using solution processed organic transistor arrays and bulk heterojunction photodiodes on thin, flexible plastic substrate

    NARCIS (Netherlands)

    Gelinck, G.H.; Kumar, A.; Moet, D.; Steen, J.L. van der; Shafique, U.; Malinowski, P.E.; Myny, K.; Rand, B.P.; Simon, M.; Rütten, W.; Douglas, A.; Jorritsma, J.; Heremans, P.L.; Andriessen, H.A.J.M.

    2013-01-01

    We describe the fabrication and characterization of large-area active-matrix X-ray/photodetector array of high quality using organic photodiodes and organic transistors. All layers with the exception of the electrodes are solution processed. Because it is processed on a very thin plastic substrate o

  12. Initial time-dependent current growth phenomenon in n-type organic transistors induced by interfacial dipole effects

    Science.gov (United States)

    Lin, Yi-Sheng; Yeh, Bo-Liang; Tsai, Min-Ruei; Cheng, Horng-Long; Liu, Shyh-Jiun; Tang, Fu-Ching; Chou, Wei-Yang

    2015-03-01

    We describe an unusual phenomenon of time-dependent current growth in organic transistors, particularly n-type transistors. For an organic transistor based on N,N-ditridecyl-3,4,9,10-perylene tetracarboxylic diimide with a polyimide dielectric layer, the time-dependent increase in the drain current and an approximately hysteresis-free electricity were obtained under dc-bias stress. These phenomena could be attributed to (a) reduction in the trap-state density located at the interface between polyimide and semiconductor, (b) gate field effect enhanced by electric dipoles within polyimide, and (c) a low interface trap lifetime. This study reveals that polymer dielectrics with moderate polar groups are suitable for application in stable organic devices.

  13. Synaptic organic transistors with a vacuum-deposited charge-trapping nanosheet

    Science.gov (United States)

    Kim, Chang-Hyun; Sung, Sujin; Yoon, Myung-Han

    2016-09-01

    Organic neuromorphic devices hold great promise for unconventional signal processing and efficient human-machine interfaces. Herein, we propose novel synaptic organic transistors devised to overcome the traditional trade-off between channel conductance and memory performance. A vacuum-processed, nanoscale metallic interlayer provides an ultra-flat surface for a high-mobility molecular film as well as a desirable degree of charge trapping, allowing for low-temperature fabrication of uniform device arrays on plastic. The device architecture is implemented by widely available electronic materials in combination with conventional deposition methods. Therefore, our results are expected to generate broader interests in incorporation of organic electronics into large-area neuromorphic systems, with potential in gate-addressable complex logic circuits and transparent multifunctional interfaces receiving direct optical and cellular stimulation.

  14. Synaptic organic transistors with a vacuum-deposited charge-trapping nanosheet

    Science.gov (United States)

    Kim, Chang-Hyun; Sung, Sujin; Yoon, Myung-Han

    2016-01-01

    Organic neuromorphic devices hold great promise for unconventional signal processing and efficient human-machine interfaces. Herein, we propose novel synaptic organic transistors devised to overcome the traditional trade-off between channel conductance and memory performance. A vacuum-processed, nanoscale metallic interlayer provides an ultra-flat surface for a high-mobility molecular film as well as a desirable degree of charge trapping, allowing for low-temperature fabrication of uniform device arrays on plastic. The device architecture is implemented by widely available electronic materials in combination with conventional deposition methods. Therefore, our results are expected to generate broader interests in incorporation of organic electronics into large-area neuromorphic systems, with potential in gate-addressable complex logic circuits and transparent multifunctional interfaces receiving direct optical and cellular stimulation. PMID:27645425

  15. The effect of pH and DNA concentration on organic thin-film transistor biosensors

    KAUST Repository

    Khan, Hadayat Ullah

    2012-03-01

    Organic electronics are beginning to attract more interest for biosensor technology as they provide an amenable interface between biology and electronics. Stable biosensor based on electronic detection platform would represent a significant advancement in technology as costs and analysis time would decrease immensely. Organic materials provide a route toward that goal due to their compatibility with electronic applications and biological molecules. In this report, we detail the effects of experimental parameters, such as pH and concentration, toward the selective detection of DNA via surface-bound peptide nucleic acid (PNA) sequences on organic transistor biosensors. The OTFT biosensors are fabricated with thin-films of the organic semiconductor, 5,5′-bis-(7-dodecyl-9H-fluoren-2-yl)-2,2′-bithiophene (DDFTTF), in which they exhibit a stable mobility of 0.2 cm 2 V -1 s -1 in buffer solutions (phosphate-buffer saline, pH 7.4 or sodium acetate, pH 7). Device performance were optimized to minimize the deleterious effects of pH on gate-bias stress such that the sensitivity toward DNA detection can be improved. In titration experiments, the surface-bound PNA probes were saturated with 50 nM of complementary target DNA, which required a 10-fold increase in concentration of single-base mismatched target DNA to achieve a similar surface saturation. The binding constant of DNA on the surface-bound PNA probes was determined from the concentration-dependent response (titration measurements) of our organic transistor biosensors. © 2011 Elsevier B.V. All rights reserved.

  16. In-situ study of pn-heterojunction interface states in organic thin film transistors

    International Nuclear Information System (INIS)

    In this paper, we have investigated the density of pn-heterojunction interface states by evaluating the threshold voltage shift with in-situ measurement of electrical characteristics of a sandwich fluorinated copper phthalocyanine/pentacene thin film transistor with various thicknesses of pentacene thin films. A threshold voltage (VT) undergoes a significant shift from + 20.6 to + 0.53 V with increasing the thickness of pentacene. When the thickness of pentacene is more than a critical thickness of 15 nm, VT undergoes hardly any shift. On the other hand, the value of mobility is lightly decreased with increasing the thickness of pentacene due to the effect of the bulk current. Thus the VT shift is attributed to the increase of drain current in the sandwich device. In order to explain the VT shift, a model was assumed in the linear region of thin film transistor operation and the VT shift agrees with a tan−1 function of film thickness. The total charge density (Q0) of 1.53 × 10−7 C/cm2 (9.56 × 1011 electrons or holes/cm2) was obtained. Furthermore, the VT shift and Q0 could be adjusted by selecting a p-type semiconductor. - Highlights: • A threshold voltage was in-situ measured in an organic sandwich thin film transistor. • Density of pn-heterojunction interface states by evaluating the threshold voltage shift. • The threshold voltage shift attributes to the increase of drain current. • In order to explain the threshold voltage shift, a model was assumed

  17. Pentacene organic ferroelectric transistors with [P(VDF-TrFE)] gate by Langmuir-Blodgett process

    Science.gov (United States)

    Sun, Yilin; Xie, Dan; Xu, Jianlong; Feng, Tingting; Zang, Yongyuan; Zhang, Cheng; Dai, Ruixuan; Meng, Xiangjian; Ji, Zhuoyu

    2015-09-01

    We report the fabrication and electrical properties of pentacene-based ferroelectric organic field-effect transistors (FeOFETs) with ultrathin poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] gate insulators. A ultrathin and uniform P(VDF-TrFE) film was successfully deposited by Langmuir-Blodgett (LB) deposition with well-defined ferroelectric microdomains at the interface between P(VDF-TrFE) films and pentacene active layers. The P(VDF-TrFE) films derived by LB deposition significantly enhance the crystallization of the upper pentacene channel films and thus the performance of our FeOFETs. Our FeOFET device achieves a threshold voltage shift of 8.56 V induced by ferroelectric polarization under different voltage sweeping directions and such enhancement indicates a great potential for future organic nonvolatile memory applications.

  18. Effect of Processing Parameters on Performance of Spray-Deposited Organic Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Jack W. Owen

    2011-01-01

    Full Text Available The performance of organic thin-film transistors (OTFTs is often strongly dependent on the fabrication procedure. In this study, we fabricate OTFTs of soluble small-molecule organic semiconductors by spray-deposition and explore the effect of processing parameters on film morphology and device mobility. In particular, we report on the effect of the nature of solvent, the pressure of the carrier gas used in deposition, and the spraying distance. We investigate the surface morphology using scanning force microscopy and show that the molecules pack along the π-stacking direction, which is the preferred charge transport direction. Our results demonstrate that we can tune the field-effect mobility of spray-deposited devices two orders of magnitude, from 10−3 cm2/Vs to 10−1 cm2/Vs, by controlling fabrication parameters.

  19. Percolation of Carbon Nanoparticles in Poly(3-Hexylthiophene Enhancing Carrier Mobility in Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Chang-Hung Lee

    2014-01-01

    Full Text Available To improve the field-effect mobility of all-inkjet-printed organic thin film transistors (OTFTs, a composite material consisted of carbon nanoparticles (CNPs and poly(3-hexylthiophene (P3HT was reported by using homemade inkjet-printing system. These all-inkjet-printed composite OTFTs represented superior characteristics compared to the all-inkjet-printed pristine P3HT OTFTs. To investigate the enhancement mechanism of the blended materials, the percolation model was established and experimentally verified to illustrate the enhancement of the electrical properties with different blending concentrations. In addition, experimental results of OTFT contact resistances showed that both contact resistance and channel resistance were halved. At the same time, X-ray diffraction measurements, Fourier transform infrared spectra, ultraviolet-visible light, and photoluminescence spectra were also accomplished to clarify the material blending effects. Therefore, this study demonstrates the potential and guideline of carbon-based nanocomposite materials in all-inkjet-printed organic electronics.

  20. Interface Engineering of Organic Thin Film Transistors with Self-assembled Organophosphonic Acids

    Science.gov (United States)

    Liu, Danqing

    Organic thin film transistors (OTFTs) are interface devices with their performance highly dependent on the interface between organic semiconductors and gate dielectrics no matter whether the organic semiconductors are processed by vacuum deposition or solution-based methods. Detailed in this thesis are studies of interface engineering for OTFTs with self-assembled organophosphonic acids, which play important roles in tuning the properties of the dielectric surface for high-performance OTFTs. The poor crystallinity of rubrene in conventional vacuum deposited films is a well-known obstacle limiting practical applications of rubrene in thin film transistors. As described in Chapter 2, a template layer of diazapentacene (DAP) is introduced to induce crystallization of rubrene in thin film transistors. This study demonstrates that DAP is a suitable template molecule with negligible contribution to the conduction channel leading to polycrystalline thin films of rubrene with field effect mobility as high as 0.68 cm2 V --1 s--1. This induced-crystallization strategy highly depends on a unique octadecylphosphonic acid (ODPA) bilayer-step surface, which plays important roles in controlling the growth of both DAP and rubrene. In solution-processed OTFTs, one key factor that affects the nucleation and growth of semiconductor molecules during solution-based processing is the wetting behavior of the semiconductor solution on the dielectric surface. Reported in Chapter 3 is a new strategy for preparing solution-processed OTFTs based on enhancing the surface energy of self-assembled monolayers (SAMs) by inserting polar oxygen atoms into the long alkyl chain of phosphonic acids. SAMs of these phosphonic acids on a high-k metal oxide layer of AlOy /TiOx lead to solution-processed n-channel OTFTs with high field effect mobility of up to 2.5 cm2 V--1 s--1 and low operational voltage. Chapter 4 puts forth a new design of SAMs for interface engineering of high-performance OTFTs. This

  1. High-mobility solution-processed copper phthalocyanine-based organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Nandu B Chaure, Andrew N Cammidge, Isabelle Chambrier, Michael J Cook, Markys G Cain, Craig E Murphy, Chandana Pal and Asim K Ray

    2011-01-01

    Full Text Available Solution-processed films of 1,4,8,11,15,18,22,25-octakis(hexyl copper phthalocyanine (CuPc6 were utilized as an active semiconducting layer in the fabrication of organic field-effect transistors (OFETs in the bottom-gate configurations using chemical vapour deposited silicon dioxide (SiO2 as gate dielectrics. The surface treatment of the gate dielectric with a self-assembled monolayer of octadecyltrichlorosilane (OTS resulted in values of 4×10−2 cm2 V−1 s−1 and 106 for saturation mobility and on/off current ratio, respectively. This improvement was accompanied by a shift in the threshold voltage from 3 V for untreated devices to -2 V for OTS treated devices. The trap density at the interface between the gate dielectric and semiconductor decreased by about one order of magnitude after the surface treatment. The transistors with the OTS treated gate dielectrics were more stable over a 30-day period in air than untreated ones.

  2. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Jooyeok Seo

    2014-09-01

    Full Text Available We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4′-pentylbiphenyl - 5CB on top of the 50 nm thick channel layer (poly(3-hexylthiophene - P3HT that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO. As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm2/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (VD and gate (VG voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of VD and VG. The best voltage combination was VD = −0.2 V and VG = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio. The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.

  3. Low operating voltage n-channel organic field effect transistor using epoxy based photoresist gate dielectric

    International Nuclear Information System (INIS)

    We report a systematic study on the dielectric properties of epoxy based positive tone photoresist and its use as a gate dielectric for n-channel organic field effect transistors (OFETs) made with N,N’-Dioctyl-3,4,9,10-perylenedicarboximinde (PTCDI-C8) as the active semiconducting layer. We find that the photoresist has high dielectric constant (k = 12 at 10 kHz) and thus can be used in fabricating low operating voltage OFET devices. Highly smooth gate dielectric surface was obtained using the photoresist with the highest root mean square (rms) roughness of 0.239 nm for the films annealed at 200 °C. Consequently, the semiconducting layer (on photoresist dielectric annealed at 100 °C) also exhibited highly uniform surface with rms roughness of 0.382 nm. The turn-on voltage (VT), inverse subthreshold slope (S) and saturation mobility of electrons (μsat) of the transistor device were estimated to be 4.3 V, 13 V decade−1 and 6 × 10−5 cm2 Vs−1, respectively, when the device was operated in ambient, which is better than some of the earlier reported works under similar experimental conditions. (paper)

  4. Controlled Growth of Ultrathin Film of Organic Semiconductors by Balancing the Competitive Processes in Dip-Coating for Organic Transistors.

    Science.gov (United States)

    Wu, Kunjie; Li, Hongwei; Li, Liqiang; Zhang, Suna; Chen, Xiaosong; Xu, Zeyang; Zhang, Xi; Hu, Wenping; Chi, Lifeng; Gao, Xike; Meng, Yancheng

    2016-06-28

    Ultrathin film with thickness below 15 nm of organic semiconductors provides excellent platform for some fundamental research and practical applications in the field of organic electronics. However, it is quite challenging to develop a general principle for the growth of uniform and continuous ultrathin film over large area. Dip-coating is a useful technique to prepare diverse structures of organic semiconductors, but the assembly of organic semiconductors in dip-coating is quite complicated, and there are no reports about the core rules for the growth of ultrathin film via dip-coating until now. In this work, we develop a general strategy for the growth of ultrathin film of organic semiconductor via dip-coating, which provides a relatively facile model to analyze the growth behavior. The balance between the three direct factors (nucleation rate, assembly rate, and recession rate) is the key to determine the growth of ultrathin film. Under the direction of this rule, ultrathin films of four organic semiconductors are obtained. The field-effect transistors constructed on the ultrathin film show good field-effect property. This work provides a general principle and systematic guideline to prepare ultrathin film of organic semiconductors via dip-coating, which would be highly meaningful for organic electronics as well as for the assembly of other materials via solution processes. PMID:27267545

  5. Controlled Growth of Ultrathin Film of Organic Semiconductors by Balancing the Competitive Processes in Dip-Coating for Organic Transistors.

    Science.gov (United States)

    Wu, Kunjie; Li, Hongwei; Li, Liqiang; Zhang, Suna; Chen, Xiaosong; Xu, Zeyang; Zhang, Xi; Hu, Wenping; Chi, Lifeng; Gao, Xike; Meng, Yancheng

    2016-06-28

    Ultrathin film with thickness below 15 nm of organic semiconductors provides excellent platform for some fundamental research and practical applications in the field of organic electronics. However, it is quite challenging to develop a general principle for the growth of uniform and continuous ultrathin film over large area. Dip-coating is a useful technique to prepare diverse structures of organic semiconductors, but the assembly of organic semiconductors in dip-coating is quite complicated, and there are no reports about the core rules for the growth of ultrathin film via dip-coating until now. In this work, we develop a general strategy for the growth of ultrathin film of organic semiconductor via dip-coating, which provides a relatively facile model to analyze the growth behavior. The balance between the three direct factors (nucleation rate, assembly rate, and recession rate) is the key to determine the growth of ultrathin film. Under the direction of this rule, ultrathin films of four organic semiconductors are obtained. The field-effect transistors constructed on the ultrathin film show good field-effect property. This work provides a general principle and systematic guideline to prepare ultrathin film of organic semiconductors via dip-coating, which would be highly meaningful for organic electronics as well as for the assembly of other materials via solution processes.

  6. Ta2O5 as gate dielectric material for low-voltage organic thin-film transistors

    NARCIS (Netherlands)

    Bartic, Carmen; Jansen, H.; Campitelli, Andrew; Borghs, Staf

    2002-01-01

    In this paper we report the use of Ta2O5 as gate dielectric material for organic thin-film transistors. Ta2O5 has already attracted a lot of attention as insulating material for VLSI applications. We have deposited Ta2O5 thin-films with different thickness by means of electron-beam evaporation. Bein

  7. Controlling of the surface energy of the gate dielectric in organic field-effect transistors by polymer blend

    NARCIS (Netherlands)

    Gao, Jia; Asadi, Kamal; Xu, Jian Bin; An, Jin

    2009-01-01

    In this letter, we demonstrate that by blending insulating polymers, one can fabricate an insulating layer with controllable surface energy for organic field-effect transistors. As a model system, we used copper phthalocyanine evaporated on layers of polymethyl metacrylate blended with polystyrene w

  8. Revealing Buried Interfaces to Understand the Origins of Threshold Voltage Shifts in Organic Field-Effect Transistors

    NARCIS (Netherlands)

    Mathijssen, Simon G. J.; Spijkman, Mark-Jan; Andringa, Anne-Marije; van Hal, Paul A.; McCulloch, Iain; Kemerink, Martijn; Janssen, Rene A. J.; de Leeuw, Dago M.

    2010-01-01

    The semiconductor of an organic field-effect transistor is stripped with adhesive tape, yielding an exposed gate dielectric, accessible for various characterization techniques. By using scanning Kelvin probe microscopy we reveal that trapped charges after gate bias stress are located at the gate die

  9. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors

    KAUST Repository

    Nielsen, Christian B.

    2016-07-22

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous envi-ronment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially availa-ble conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, elec-trochromic properties, operational voltage and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT based devices, and show stability under aqueous oper-ation without the need for formulation additives and cross-linkers.

  10. Effects of P3HT concentration on the performance of organic field effect transistors

    Institute of Scientific and Technical Information of China (English)

    JIANG Chun-xia; CHENG Xiao-man; WU Xiao-ming; YANG Xiao-yan; YIN Bin; HUA Yu-lin; WEI Jun; YIN Shou-gen

    2011-01-01

    @@ Top-contact organic field effect transistors (OFETs) based on poly(3-hexylthiophene) (P3HT) with different concentrations in chloroform (CHCl3) are fabricated.The output characteristics indicate that the P3HT concentration has significant influence on the OFET devices.The performance of the devices firstly is enhanced with increasing the P3HT concentration, and then decreases.The optimized devices with the P3HT concentration of 2 mg/mL show the best performance.The fieldeffect mobility is up to 1.4 × 10-2 cm2/Vs, the threshold voltage (Vt) is as low as -20 V, and the current on/off ratio (Ion/off) is close to the order of 104.The resu1ts suggest that the P3HT aggregation patterns induced by different concentrations can improve the performance of the OFETs.

  11. Performance of pentacene-based organic field effect transistors using different polymer gate dielectrics

    Institute of Scientific and Technical Information of China (English)

    WU Ren-lei; CHENG Xiao-man; ZHENG Hong; YIN Shou-gen

    2009-01-01

    Pentacene-based organic field effect transistors (OFETs) are fabricated using poly(methyl methacrylate) (PMMA) and polyimide (PI) as gate dielectrics, respectively. The fabricated OFETs exhibit reasonable device characteristics. The field-effect mobility, threshold voltage, and on/off current radio are determined to be 3.214 × 10-2 cm2 / Vs, -28 V, and 1 × 103 respectively for OFETs with PMMA as gate dielectrics, and 7.306×10-3cm2 / Vs, -21 V, and 2 ×102 for OFETs with PI. Furthermore, the dielectric properties of gate insulator layer are tested and the dipole effect at the semiconductor/dielectrics interface is also analyzed by a model of energy level diagram.

  12. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors.

    Science.gov (United States)

    Nielsen, Christian B; Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Bandiello, Enrico; Niazi, Muhammad R; Hanifi, David A; Sessolo, Michele; Amassian, Aram; Malliaras, George G; Rivnay, Jonathan; McCulloch, Iain

    2016-08-17

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers. PMID:27444189

  13. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors.

    Science.gov (United States)

    Nielsen, Christian B; Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Bandiello, Enrico; Niazi, Muhammad R; Hanifi, David A; Sessolo, Michele; Amassian, Aram; Malliaras, George G; Rivnay, Jonathan; McCulloch, Iain

    2016-08-17

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers.

  14. Thienoacene-fused pentalenes: Syntheses, structures, physical properties and applications for organic field-effect transistors

    KAUST Repository

    Dai, Gaole

    2014-11-27

    Three soluble and stable thienoacene-fused pentalene derivatives (1-3) with different π-conjugation lengths were synthesized. X-ray crystallographic analysis and density functional theory (DFT) calculations revealed their unique geometric and electronic structures due to the interaction between the aromatic thienoacene units and antiaromatic pentalene moiety. As a result, they all possess a small energy gap and show amphoteric redox behaviour. Time dependent (TD) DFT calculations were used to explain their unique electronic absorption spectra. These new compounds exhibited good thermal stability and ordered packing in solid state and thus their applications in organic field-effect transistors (OFETs) were also investigated. The highest field-effect hole mobility of 0.016, 0.036 and 0.001 cm2 V-1 s-1 was achieved for solution-processed thin films of 1-3, respectively.

  15. Hysteresis mechanism and control in pentacene organic field-effect transistors with polymer dielectric

    Directory of Open Access Journals (Sweden)

    Wei Huang

    2013-05-01

    Full Text Available Hysteresis mechanism of pentacene organic field-effect transistors (OFETs with polyvinyl alcohol (PVA and/or polymethyl methacrylate (PMMA dielectrics is studied. Through analyzing the electrical characteristics of OFETs with various PVA/PMMA arrangements, it shows that charge, which is trapped in PVA bulk and at the interface of pentacene/PVA, is one of the origins of hysteresis. The results also show that memory window is proportional to both trap amount in PVA and charge density at the gate/PVA or PVA/pentacene interfaces. Hence, the controllable memory window of around 0 ∼ 10 V can be realized by controlling the thickness and combination of triple-layer polymer dielectrics.

  16. Improved Performance by a Double-Insulator Layer in Organic Thin-Film Transistors

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; SHI Jia-Wei; GUO Shu-Xu; ZHANG Hong-Mei; QUAN Bao-Fu; MA Dong-Ge

    2006-01-01

    @@ Organic thin film transistors based on pentacene are fabricated by the method of full evaporation. The thickness of insulator film can be controlled accurately, which influences the device operation voltage markedly. Compared to the devices with a single-insulator layer, the electric performance of devices by using a double-insulator as the gate dielectric has good improvement. It is found that the gate leakage current can be reduced over one order of magnitude, and the on-state current can be enhanced over one order of magnitude. The devices with double-insulator layer exhibit field-effect mobility as large as 0.14 cm2/Vs and near the zero threshold voltage.The results demonstrate that using a proper double insulator as the gate dielectrics is an effective method to fabricate OTFTs with high electrical performance.

  17. Internal additive noise effects in stochastic resonance using organic field effect transistor

    Science.gov (United States)

    Suzuki, Yoshiharu; Matsubara, Kiyohiko; Asakawa, Naoki

    2016-08-01

    Stochastic resonance phenomenon was observed in organic field effect transistor using poly(3-hexylthiophene), which enhances performance of signal transmission with application of noise. The enhancement of correlation coefficient between the input and output signals was low, and the variation of correlation coefficient was not remarkable with respect to the intensity of external noise, which was due to the existence of internal additive noise following the nonlinear threshold response. In other words, internal additive noise plays a positive role on the capability of approximately constant signal transmission regardless of noise intensity, which can be said "homeostatic" behavior or "noise robustness" against external noise. Furthermore, internal additive noise causes emergence of the stochastic resonance effect even on the threshold unit without internal additive noise on which the correlation coefficient usually decreases monotonically.

  18. High performance organic transistor active-matrix driver developed on paper substrate

    Science.gov (United States)

    Peng, Boyu; Ren, Xiaochen; Wang, Zongrong; Wang, Xinyu; Roberts, Robert C.; Chan, Paddy K. L.

    2014-09-01

    The fabrication of electronic circuits on unconventional substrates largely broadens their application areas. For example, green electronics achieved through utilization of biodegradable or recyclable substrates, can mitigate the solid waste problems that arise at the end of their lifespan. Here, we combine screen-printing, high precision laser drilling and thermal evaporation, to fabricate organic field effect transistor (OFET) active-matrix (AM) arrays onto standard printer paper. The devices show a mobility and on/off ratio as high as 0.56 cm2V-1s-1 and 109 respectively. Small electrode overlap gives rise to a cut-off frequency of 39 kHz, which supports that our AM array is suitable for novel practical applications. We demonstrate an 8 × 8 AM light emitting diode (LED) driver with programmable scanning and information display functions. The AM array structure has excellent potential for scaling up.

  19. Persistent photocurrent (PPC) in solution-processed organic thin film transistors: Mechanisms of gate voltage control

    Science.gov (United States)

    Singh, Subhash; Mohapatra, Y. N.

    2016-07-01

    There is a growing need to understand mechanisms of photoresponse in devices based on organic semiconductor thin films and interfaces. The phenomenon of persistent photocurrent (PPC) has been systematically investigated in solution processed TIPS-Pentacene based organic thin film transistors (OTFTs) as an important example of an organic semiconductor material system. With increasing light intensity from dark to 385 mW/cm2, there is a significant shift in threshold voltage (VTh) while the filed-effect mobility remains unchanged. The OTFT shows large photoresponse under white light illumination due to exponential tail states with characteristic energy parameter of 86 meV. The photo-induced current is observed to persist even for several hours after turning the light off. To investigate the origin of PPC, its quenching mechanism is investigated by a variety of methods involving a combination of gate bias, illumination and temperature. We show that a coherent model of trap-charge induced carrier concentration is able to account for the quenching behavior. Analysis of isothermal transients using time-analyzed transient spectroscopy shows that the emission rates are activated and are also field enhanced due to Poole-Frankel effect. The results shed light on the nature, origin, and energetic distribution of the traps controlling PPC in solution processed organic semiconductors and their interfaces.

  20. Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

    Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

  1. Interface Dipole : Effects on Threshold Voltage and Mobility for both Amorphous and Poly-crystalline Organic Field Effect Transistors

    OpenAIRE

    Celle, C.; Suspene, C.; Ternisien, M.; Lenfant, S.; Guerin, D.; Smaali, K.; Lmimouni, K.; Simonato, J. P.; Vuillaume, D.

    2014-01-01

    We report a detailed comparison on the role of a self-assembled monolayer (SAM) of dipolar molecules on the threshold voltage and charge carrier mobility of organic field-effect transistor (OFET) made of both amorphous and polycrystalline organic semiconductors. We show that the same relationship between the threshold voltage and the dipole-induced charges in the SAM holds when both types of devices are fabricated on strictly identical base substrates. Charge carrier mobilities, almost consta...

  2. High-performance nonvolatile organic transistor memory devices using the electrets of semiconducting blends.

    Science.gov (United States)

    Chiu, Yu-Cheng; Chen, Tzu-Ying; Chen, Yougen; Satoh, Toshifumi; Kakuchi, Toyoji; Chen, Wen-Chang

    2014-08-13

    Organic nonvolatile transistor memory devices of the n-type semiconductor N,N'-bis(2-phenylethyl)-perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI) were prepared using various electrets (i.e., three-armed star-shaped poly[4-(diphenylamino)benzyl methacrylate] (N(PTPMA)3) and its blends with 6,6-phenyl-C61-butyric acid methyl ester (PCBM), 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pen) or ferrocene). In the device using the PCBM:N(PTPMA)3 blend electret, it changed its memory feature from a write-once-read-many (WORM) type to a flash type as the PCBM content increased and could be operated repeatedly based on a tunneling process. The large shifts on the reversible transfer curves and the hysteresis after implementing a gate bias indicated the considerable charge storage in the electret layer. On the other hand, the memory characteristics showed a flash type and a WORM characteristic, respectively, using the donor/donor electrets TIPS-pen:N(PTPMA)3 and ferrocene:N(PTPMA)3. The variation on the memory characteristics was attributed to the difference of energy barrier at the interface when different types of electret materials were employed. All the studied memory devices exhibited a long retention over 10(4) s with a highly stable read-out current. In addition, the afore-discussed memory devices by inserting another electret layer of poly(methacrylic acid) (PMAA) between the BPE-PTCDI layer and the semiconducting blend layer enhanced the write-read-erase-read (WRER) operation cycle as high as 200 times. This study suggested that the energy level and charge transfer in the blend electret had a significant effect on tuning the characteristics of nonvolatile transistor memory devices.

  3. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jooyeok; Lee, Chulyeon; Han, Hyemi; Lee, Sooyong; Nam, Sungho; Kim, Youngkyoo, E-mail: ykimm@knu.ac.kr [Organic Nanoelectronics Laboratory, Department of Chemical Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Kim, Hwajeong [Organic Nanoelectronics Laboratory, Department of Chemical Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Priority Research Center, Research Institute of Advanced Energy Technology, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Lee, Joon-Hyung [School of Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Park, Soo-Young; Kang, Inn-Kyu [Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of)

    2014-09-15

    We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET) structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4{sup ′}-pentylbiphenyl - 5CB) on top of the 50 nm thick channel layer (poly(3-hexylthiophene) - P3HT) that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO). As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s) was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm{sup 2}/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (V{sub D}) and gate (V{sub G}) voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of V{sub D} and V{sub G}. The best voltage combination was V{sub D} = −0.2 V and V{sub G} = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio). The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.

  4. Impact of semiconductor/metal interfaces on contact resistance and operating speed of organic thin film transistors

    KAUST Repository

    Wondmagegn, Wudyalew T.

    2010-09-24

    The contact resistance of field effect transistors based on pentacene and parylene has been investigated by experimental and numerical analysis. The device simulation was performed using finite element two-dimensional drift-diffusion simulation taking into account field-dependent mobility, interface/bulk trap states and fixed charge density at the organic/insulator interface. The width-normalized contact resistance extracted from simulation which included an interface dipole layer between the gold source/drain electrodes and pentacene was 91 kΩcm. However, contact resistance extracted from the simulation, without consideration of interface dipole was 52.4 kΩcm, which is about half of the experimentally extracted 108 kΩcm. This indicates that interface dipoles are critical effects which degrade performances of organic field effect transistors by increasing the contact resistance. Using numerical calculations and circuit simulations, we have predicted a 1 MHz switching frequency for a 1 μm channel length transistor without dipole interface between gold and pentacene. The transistor with dipole interface is predicted, via the same methods, to exhibit an operating frequency of less than 0.5 MHz. © 2010 Springer Science+Business Media LLC.

  5. Temperature and layer thickness dependent in situ investigations on epindolidione organic thin-film transistors

    Science.gov (United States)

    Lassnig, R.; Striedinger, B.; Jones, A.O.F.; Scherwitzl, B.; Fian, A.; Głowacl, E.D.; Stadlober, B.; Winkler, A.

    2016-01-01

    We report on in situ performance evaluations as a function of layer thickness and substrate temperature for bottom-gate, bottom-gold contact epindolidione organic thin-film transistors on various gate dielectrics. Experiments were carried out under ultra-high vacuum conditions, enabling quasi-simultaneous electrical and surface analysis. Auger electron spectroscopy and thermal desorption spectroscopy (TDS) were applied to characterize the quality of the substrate surface and the thermal stability of the organic films. Ex situ atomic force microscopy (AFM) was used to gain additional information on the layer formation and surface morphology of the hydrogen-bonded organic pigment. The examined gate dielectrics included SiO2, in its untreated and sputtered forms, as well as the spin-coated organic capping layers poly(vinyl-cinnamate) (PVCi) and poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE, from the class of polynorbornenes). TDS and AFM revealed Volmer-Weber island growth dominated film formation with no evidence of a subjacent wetting layer. This growth mode is responsible for the comparably high coverage required for transistor behavior at 90–95% of a monolayer composed of standing molecules. Surface sputtering and an increased sample temperature during epindolidione deposition augmented the surface diffusion of adsorbing molecules and therefore led to a lower number of better-ordered islands. Consequently, while the onset of charge transport was delayed, higher saturation mobility was obtained. The highest, bottom-contact configuration, mobilities of approximately 2.5 × 10−3cm2/Vs were found for high coverages (50 nm) on sputtered samples. The coverage dependence of the mobility showed very different characteristics for the different gate dielectrics, while the change of the threshold voltage with coverage was approximately the same for all systems. An apparent decrease of the mobility with increasing coverage on the

  6. Organic field-effect transistors based on a crosslinkable polymer blend as the semiconducting layer

    Science.gov (United States)

    Yan, He; Yoon, Myung-Han; Facchetti, Antonio; Marks, Tobin J.

    2005-10-01

    For fabrication of top-gate polymer-based organic field-effect transistors (OFETs), it is essential that the semiconducting layer remain intact during spin coating of the overlying dielectric layer. This requirement severely limits the applicable solvent and materials combinations. We show here that a crosslinkable polymer blend consisting of a p-type semiconducting polymer {e.g., TFB; poly[9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine]} and an electroactive crosslinkable silyl reagent {e.g., TPDSi2; 4,4'-bis[(p-trichloro-silylpropylphenyl)phenylamino]biphenyl} is effective as the semiconducting layer in a top-gate bottom-contact OFET device. The TFB +TPDSi2 semiconducting blend is prepared by spin-coating in ambient. The crosslinking process occurs during spin-coating in air and is completed by curing at 90 °C, which renders the resulting film insoluble in common organic solvents and allows subsequent deposition of dielectric layers from a wide range of organic solvents. We also show that the presence of TPDSi2 in the semiconductor layer significantly reduces typical TFB-source-drain threshold voltages in bottom-contact devices, likely due to favorable interfacial TPDSi2-gold electrode interactions.

  7. Organic ferroelectric gate field-effect transistor memory using high-mobility rubrene thin film

    Science.gov (United States)

    Kanashima, Takeshi; Katsura, Yuu; Okuyama, Masanori

    2014-01-01

    An organic ferroelectric gate field-effect transistor (FET) memory has been fabricated using an organic semiconductor of rubrene thin film with a high mobility and a gate insulating layer of poly(vinylidene fluoride-tetrafluoroethylene) [P(VDF-TeFE)] thin film. A rubrene thin-film sheet was grown by physical vapor transport (PVT), and placed onto a spin-coated P(VDF-TeFE) thin-film layer, and Au source and drain electrodes were formed on this rubrene thin film. A hysteresis loop of the drain current-gate voltage (ID-VG) characteristic has been clearly observed in the ferroelectric gate FET, and is caused by the ferroelectricity. The maximum drain current is 1.5 × 10-6 A, which is about two orders of magnitude larger than that of the P(VDF-TeFE) gate FET using a pentacene thin film. Moreover, the mobility of this organic ferroelectric gate FET using rubrene thin film is 0.71 cm2 V-1 s-1, which is 35 times larger than that of the FET with pentacene thin film.

  8. Solution-processible organic-inorganic hybrid bipolar field-effect transistors

    Science.gov (United States)

    Chae, Gil Jo; Kim, Kang Dae; Cho, Shinuk; Walker, Bright; Seo, Jung Hwa

    2016-04-01

    Organic-inorganic hybrid bipolar field-effect transistors (HBFETs) comprising a layer of p-type organic poly(3-hexylthiophene) (P3HT) separated from a parallel layer of n-type inorganic zinc oxide (ZnO) were demonstrated by solution processing. In order to achieve balanced hole and electron mobilities, we initially optimized the hole-transporting P3HT channel by the addition of the polar non-solvent acetonitrile (AN) to P3HT solutions in chloroform, which induced a selfassembled nano-fibril morphology and an enhancement of hole mobilities. For the electron channel, a wet-chemically-prepared ZnO layer was optimized by thermal annealing. Unipolar P3HT FET with 5% AN exhibited the highest hole mobility of 7.20 × 10-2 cm2V-1s-1 while the highest electron mobility (3.64 × 10-2 cm2V-1s-1) was observed in unipolar ZnO FETs annealed at 200°C. The organic-inorganic HBFETs consisting of the P3HT layer with 5% AN and ZnO annealed at 200°C exhibited well-balanced hole and electron mobilities of 1.94 × 10-2 cm2V-1s-1 and 1.98 × 10-2 cm2V-1s-1, respectively.

  9. Flexible suspended gate organic thin-film transistors for ultra-sensitive pressure detection

    Science.gov (United States)

    Zang, Yaping; Zhang, Fengjiao; Huang, Dazhen; Gao, Xike; di, Chong-An; Zhu, Daoben

    2015-03-01

    The utilization of organic devices as pressure-sensing elements in artificial intelligence and healthcare applications represents a fascinating opportunity for the next-generation electronic products. To satisfy the critical requirements of these promising applications, the low-cost construction of large-area ultra-sensitive organic pressure devices with outstanding flexibility is highly desired. Here we present flexible suspended gate organic thin-film transistors (SGOTFTs) as a model platform that enables ultra-sensitive pressure detection. More importantly, the unique device geometry of SGOTFTs allows the fine-tuning of their sensitivity by the suspended gate. An unprecedented sensitivity of 192 kPa-1, a low limit-of-detection pressure of <0.5 Pa and a short response time of 10 ms were successfully realized, allowing the real-time detection of acoustic waves. These excellent sensing properties of SGOTFTs, together with their advantages of facile large-area fabrication and versatility in detecting various pressure signals, make SGOTFTs a powerful strategy for spatial pressure mapping in practical applications.

  10. Fabrication of water-stable organic transistors using crystalline rubrene thin-film and polymer-treated dielectric (Presentation Recording)

    Science.gov (United States)

    Kim, Jaejoon; Lee, Hyoek Moo; Cho, Sung Oh

    2015-10-01

    For the real application of organic electronics, stable operation of electronic devices in humid or aqueous condition is essential and desirable. However, most of organic semiconductors were very weak to the oxygen or water and especially, cannot be operated well in aqueous condition without an encapsulation. Here, we present water-stable organic thin-film transistors with highly crystallized rubrene and polymer-treated dielectrics. These high water-stability could be achieved by two factors. First, rubrene, a well-known p-type semiconducting material, showed high air and water stability after the crystallization of `abrupt heating'. By the fabrication and aqueous operation of rubrene thin film transistor, we could show the water stability of crystallized thin-film rubrene. Such high environmental stability is attributed to the fact that rubrene has comparatively low HOMO level of -5.4 eV and large bandgap energy of 3.2 eV and that the rubrene thin-film is composed of well-interconnected orthorhombic rubrene crystals. Second, the polymer-treatment of dielectrics can enhance long-term water stability of fabricated rubrene thin-film transistor. By the complete immersion test of transistors, we could characterize the increase of water-stability after the treatment of dielectrics with cross-linked polymer. For this purpose, polystyrene is cross-linked by electron irradiation and the water penetration into semiconductor/dielectric interface was decreased due to the decreased surface energy of polymer dielectric compared to the SiO₂. The fabricated rubrene thin-film transistors showed a field-effect mobility of ~0.5 cm2V-1s-1 and long-term stability under ambient and aqueous conditions. Also, we investigated their potential applications in chemical or bio sensors.

  11. Organic Memory Devices: 2D Mica Crystal as Electret in Organic Field-Effect Transistors for Multistate Memory (Adv. Mater. 19/2016).

    Science.gov (United States)

    Zhang, Xiaotao; He, Yudong; Li, Rongjin; Dong, Huanli; Hu, Wenping

    2016-05-01

    R. Li, H. Dong, and co-workers describe the exfoliation of cheap and abundant minerals, such as mica, into nanometer-thick 2D crystals with atomically flat surfaces. As described on page 3755, the application of the 2D electret in organic field-effect transistors is well-suited for flexible nonvolatile memory devices. Stored information can be retrieved even after power cycling. Moreover, the devices can be used as full-function transistors with a low-resistance and a high-resistance state.

  12. High-performance controllable ambipolar infrared phototransistors based on graphene-quantum dot hybrid

    CERN Document Server

    Wang, Ran; Wang, Haiyang; Song, Xiaoxian; Jin, Lufan; Dai, Haitao; Wu, Sen; Yao, Jianquan

    2014-01-01

    The field effect transistors (FETs) exhibited ultrahigh responsivity (107 A/W) to infrared light with great improvement of mobility in graphene / PbS quantum dot (QD) hybrid. These reported transistors are either unipolar or depletion mode devices. In this paper, we presented and fabricated conveniently-controlled grapheme / PbS QD hybrid FETs. Through the investigation on electric and optoelectronic properties, the ambipolar FETs (normally OFF) can be switched ON by raising gate voltage (VG) up to 3.7 V and -0.8 V in the first and third quadrants. Near these thresholds (VT) each carrier species shows comparable mobility (~ 300 cm2V-1s-1). Photo-responsivity reach ~ 107 A/W near each threshold and it will linearly increases with (VG-VT). These hybrid FETs become strongly competitive candidates for devices in flexible integrated circuits with low cost, large area, low-energy consumption and high performances.

  13. Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Jaekyun Kim

    2015-10-01

    Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

  14. Heterogeneous nucleation promotes carrier transport in solution-processed organic field-effect transistors

    KAUST Repository

    Li, Ruipeng

    2012-09-04

    A new way to investigate and control the growth of solution-cast thin films is presented. The combination of in situ quartz crystal microbalance measurements with dissipation capabilities (QCM-D) and in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) in an environmental chamber provides unique quantitative insights into the time-evolution of the concentration of the solution, the onset of nucleation, and the mode of growth of the organic semiconductor under varied drying conditions. It is demonstrated that careful control over the kinetics of solution drying enhances carrier transport significantly by promoting phase transformation predominantly via heterogeneous nucleation and sustained surface growth of a highly lamellar structure at the solid-liquid interface at the expense of homogeneous nucleation. A new way to investigate and control the growth of drop-cast thin films is presented. The solution-processing of small-molecule thin films of TIPS-pentacene is investigated using time-resolved techniques to reveal the mechanisms of nucleation and growth leading to solid film formation. By tuning the drying speed of the solution, the balance between surface and bulk growth modes is altered, thereby controlling the lamellar formation and tuning the carrier mobility in organic field-effect transistors Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Temperature and composition-dependent density of states in organic small-molecule/polymer blend transistors

    Science.gov (United States)

    Hunter, Simon; Mottram, Alexander D.; Anthopoulos, Thomas D.

    2016-07-01

    The density of trap states (DOS) in organic p-type transistors based on the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TES ADT), the polymer poly(triarylamine) and blends thereof are investigated. The DOS in these devices are measured as a function of semiconductor composition and operating temperature. We show that increasing operating temperature causes a broadening of the DOS below 250 K. Characteristic trap depths of ˜15 meV are measured at 100 K, increasing to between 20 and 50 meV at room-temperature, dependent on the semiconductor composition. Semiconductor films with high concentrations of diF-TES ADT exhibit both a greater density of trap states as well as broader DOS distributions when measured at room-temperature. These results shed light on the underlying charge transport mechanisms in organic blend semiconductors and the apparent freezing-out of hole conduction through the polymer and mixed polymer/small molecule phases at temperatures below 225 K.

  16. Polysilsesquioxanes for Gate-Insulating Materials of Organic Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Kimihiro Matsukawa

    2012-01-01

    Full Text Available Printable organic thin-film transistor (O-TFT is one of the most recognized technical issues nowadays. Our recent progress on the formation of organic-inorganic hybrid thin films consists of polymethylsilsesquioxane (PMSQ, and its applications for the gate-insulating layer of O-TFTs are introduced in this paper. PMSQ synthesized in toluene solution with formic acid catalyst exhibited the electric resistivity of higher than 1014 Ω cm after thermal treatment at 150°C, and the very low concentration of residual silanol groups in PMSQ was confirmed. The PMSQ film contains no mobile ionic impurities, and this is also important property for the practical use for the gate-insulating materials. In the case of top-contact type TFT using poly(3-hexylthiophene (P3HT with PMSQ gate-insulating layer, the device properties were comparable with the TFTs having thermally grown SiO2 gate-insulating layer. The feasibility of PMSQ as a gate-insulating material for O-TFTs, which was fabricated on a flexible plastic substrate, has been demonstrated. Moreover, by the modification of PMSQ, further functionalities, such as surface hydrophobicity, high permittivity that allows low driving voltage, and photocurability that allows photolithography, could be appended to the PMSQ gate-insulating layers.

  17. Sensing of EGTA Mediated Barrier Tissue Disruption with an Organic Transistor

    Directory of Open Access Journals (Sweden)

    Scherrine Tria

    2013-01-01

    Full Text Available Barrier tissue protects the body against external factors by restricting the passage of molecules. The gastrointestinal epithelium is an example of barrier tissue with the primary purpose of allowing the passage of ions and nutrients, while restricting the passage of pathogens and toxins. It is well known that the loss of barrier function can be instigated by a decrease in extracellular calcium levels, leading to changes in protein conformation and an increase in paracellular transport. In this study, ethylene glycol-bis(beta-aminoethyl ether-N,N,N',N'-tetra acetic acid (EGTA, a calcium chelator, was used to disrupt the gastrointestinal epithelial barrier. The effect of EGTA on barrier tissue was monitored by a novel label-free method based on an organic electrochemical transistor (OECT integrated with living cells and validated against conventional methods for measuring barrier tissue integrity. We demonstrate that the OECT can detect breaches in barrier tissue upon exposure to EGTA with the same sensitivity as existing methods but with increased temporal resolution. Due to the potential of low cost processing techniques and the flexibility in design associated with organic electronics, the OECT has great potential for high-throughput, disposable sensing and diagnostics.

  18. Roll-to-roll compatible organic thin film transistor manufacturing technique by printing, lamination, and laser ablation

    International Nuclear Information System (INIS)

    We present roll-to-roll printing compatible techniques for manufacturing organic thin film transistors using two separately processed foils that are laminated together. The introduction of heat-assisted lamination opens up possibilities for material and processing combinations. The lamination of two separately processed substrates together will allow usage of pre-patterned electrodes on both substrates and materials with non-compatible solvents. Also, the surface microstructure is formed differently when laminating dry films together compared to film formation from liquid phase. Demonstrator transistors, inverters and ring oscillators were produced using lamination techniques. Finally, a roll-to-roll compatible lamination concept is proposed where also the source and drain electrodes are patterned by laser ablation. The demonstrator transistors have shown very good lifetime in air, which is contributed partly to the good material combination and partly to the enhanced interface formation in heat-assisted lamination process. - Highlights: • A roll-to-roll compatible lamination technique for printed electronics is proposed. • Laser ablation allows highly defined metal top and bottom electrodes. • Method opens up processing possibilities for incompatible materials and solvents. • Shearing forces may enhance molecular orientation and packing. • An air stable polymer transistor is demonstrated with a lifetime of years

  19. A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications

    Science.gov (United States)

    Someya, Takao; Sekitani, Tsuyoshi; Iba, Shingo; Kato, Yusaku; Kawaguchi, Hiroshi; Sakurai, Takayasu

    2004-07-01

    It is now widely accepted that skin sensitivity will be very important for future robots used by humans in daily life for housekeeping and entertainment purposes. Despite this fact, relatively little progress has been made in the field of pressure recognition compared to the areas of sight and voice recognition, mainly because good artificial "electronic skin" with a large area and mechanical flexibility is not yet available. The fabrication of a sensitive skin consisting of thousands of pressure sensors would require a flexible switching matrix that cannot be realized with present silicon-based electronics. Organic field-effect transistors can substitute for such conventional electronics because organic circuits are inherently flexible and potentially ultralow in cost even for a large area. Thus, integration of organic transistors and rubber pressure sensors, both of which can be produced by low-cost processing technology such as large-area printing technology, will provide an ideal solution to realize a practical artificial skin, whose feasibility has been demonstrated in this paper. Pressure images have been taken by flexible active matrix drivers with organic transistors whose mobility reaches as high as 1.4 cm2/V·s. The device is electrically functional even when it is wrapped around a cylindrical bar with a 2-mm radius.

  20. Characteristics of InAs/AlGaAs self-organized quantum dot modulation doped field effect transistors

    Science.gov (United States)

    Phillips, J.; Kamath, K.; Brock, T.; Bhattacharya, P.

    1998-06-01

    We have investigated the dc characteristics of InGaAs/AlGaAs modulation doped field effect transistors in which a layer of self-organized InAs quantum dots is inserted adjacent to the pseudomorphic quantum well channel. Distinct steps and a negative differential resistance are observed in the current-voltage characteristics at room temperature and lower temperatures. These are attributed to conduction through the bound states in the quantum dots.

  1. Enhancement of Ambipolar Diffusion Rates through Field Fluctuations

    CERN Document Server

    Fatuzzo, M; Fatuzzo, Marco; Adams, Fred C.

    2002-01-01

    Previous treatments of ambipolar diffusion in star-forming molecular clouds do not consider the effects of fluctuations in the fluid fields about their mean values. This paper generalizes the ambipolar diffusion problem in molecular cloud layers to include such fluctuations. Because magnetic diffusion is a nonlinear process, fluctuations can lead to an enhancement of the ambipolar diffusion rate. In addition, the stochastic nature of the process makes the ambipolar diffusion time take on a distribution of different values. In this paper, we focus on the case of long wavelength fluctuations and find that the rate of ambipolar diffusion increases by a significant factor $\\Lambda \\sim 1 - 10$. The corresponding decrease in the magnetic diffusion time helps make ambipolar diffusion more consistent with observations.

  2. Ambipolar Drift Heating in Turbulent Molecular Clouds

    CERN Document Server

    Padoan, P; Nordlund, A A; Padoan, Paolo

    1999-01-01

    Although thermal pressure is unimportant dynamically in most molecular gas, the temperature is an important diagnostic of dynamical processes and physical conditions. This is the first of two papers on thermal equilibrium in molecular clouds. We present calculations of frictional heating by ion-neutral (or ambipolar) drift in three-dimensional simulations of turbulent, magnetized molecular clouds. We show that ambipolar drift heating is a strong function of position in a turbulent cloud, and its average value can be significantly larger than the average cosmic ray heating rate. The volume averaged heating rate per unit volume due to ambipolar drift, H_AD ~ |JxB|^2 ~ B^4/L_B^2, is found to depend on the rms Alfvenic Mach number, M_A, and on the average field strength, as H_AD ~ M_A^2^4. This implies that the typical scale of variation of the magnetic field, L_B, is inversely proportional to M_A, which we also demonstrate.

  3. Ambipolar diffusion in smoothed particle magnetohydrodynamics

    CERN Document Server

    Wurster, James; Ayliffe, Ben A

    2014-01-01

    In partially ionised plasmas, the magnetic field can become decoupled from the neutral gas and diffuse through it in a process known as ambipolar diffusion. Although ambipolar diffusion has been implemented in several grid codes, we here provide an implementation in smoothed particle magnetohydrodynamics (SPMHD). We use the strong coupling approximation in which the ion density is negligible, allowing a single fluid approach. The equations are derived to conserve energy, and to provide a positive definite contribution to the entropy. We test the implementation in both a simple 1D SPMHD code and the fully 3D code PHANTOM. The wave damping test yields agreement within 0.03-2 per cent of the analytical result, depending on the value of the collisional coupling constant. The oblique C-shocks test yields results that typically agree within 4 per cent of the semi-analytical result. Our algorithm is therefore suitable for exploring the effect ambipolar diffusion has on physical processes, such as the formation of st...

  4. Investigation of protein detection parameters using nanofunctionalized organic field-effect transistors.

    Science.gov (United States)

    Hammock, Mallory L; Knopfmacher, Oren; Naab, Benjamin D; Tok, Jeffrey B-H; Bao, Zhenan

    2013-05-28

    Biodetection using organic field-effect transistors (OFETs) is gaining increasing interest for applications as diverse as food security, environmental monitoring, and medical diagnostics. However, there still lacks a comprehensive, empirical study on the fundamental limits of OFET sensors. In this paper, we present a thorough study of the various parameters affecting biosensing using an OFET decorated with gold nanoparticle (AuNP) binding sites. These parameters include the spacing between receptors, pH of the buffer, and ionic strength of the buffer. To this end, we employed the thrombin protein and its corresponding DNA binding aptamer to form our model detection system. We demonstrate a detection limit of 100 pM for this protein with high selectivity over other proteases in situ. We describe herein a feasible approach for protein detection with OFETs and a thorough investigation of parameters governing biodetection events using OFETs. Our obtained results should provide important guidelines to tailor the sensor's dynamic range to suit other desired OFET-based biodetection applications. PMID:23597051

  5. Fluorinated polyimide gate dielectrics for the advancing the electrical stability of organic field-effect transistors.

    Science.gov (United States)

    Baek, Yonghwa; Lim, Sooman; Yoo, Eun Joo; Kim, Lae Ho; Kim, Haekyoung; Lee, Seung Woo; Kim, Se Hyun; Park, Chan Eon

    2014-09-10

    Organic field-effect transistors (OFETs) that operated with good electrical stability were prepared by synthesizing fluorinated polyimide (PI) gate dielectrics based on 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI. 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI contain 6 and 18 fluorine atoms per repeat unit, respectively. These fluorinated polymers provided smooth surface topographies and surface energies that decreased as the number of fluorine atoms in the polymer backbone increased. These properties led to a better crystalline morphology in the semiconductor film grown over their surfaces. The number of fluorine atoms in the PI backbone increased, the field-effect mobility improved, and the threshold voltage shifted toward positive values (from -0.38 to +2.21 V) in the OFETs with pentacene and triethylsilylethynyl anthradithiophene. In addition, the highly fluorinated polyimide dielectric showed negligible hysteresis and a notable gate bias stability under both a N2 environment and ambient air.

  6. Atomically-thin molecular layers for electrode modification of organic transistors.

    Science.gov (United States)

    Gim, Yuseong; Kang, Boseok; Kim, BongSoo; Kim, Sun-Guk; Lee, Joong-Hee; Cho, Kilwon; Ku, Bon-Cheol; Cho, Jeong Ho

    2015-09-01

    Atomically-thin molecular layers of aryl-functionalized graphene oxides (GOs) were used to modify the surface characteristics of source-drain electrodes to improve the performances of organic field-effect transistor (OFET) devices. The GOs were functionalized with various aryl diazonium salts, including 4-nitroaniline, 4-fluoroaniline, or 4-methoxyaniline, to produce several types of GOs with different surface functional groups (NO2-Ph-GO, F-Ph-GO, or CH3O-Ph-GO, respectively). The deposition of aryl-functionalized GOs or their reduced derivatives onto metal electrode surfaces dramatically enhanced the electrical performances of both p-type and n-type OFETs relative to the performances of OFETs prepared without the GO modification layer. Among the functionalized rGOs, CH3O-Ph-rGO yielded the highest hole mobility of 0.55 cm(2) V(-1) s(-1) and electron mobility of 0.17 cm(2) V(-1) s(-1) in p-type and n-type FETs, respectively. Two governing factors: (1) the work function of the modified electrodes and (2) the crystalline microstructures of the benchmark semiconductors grown on the modified electrode surface were systematically investigated to reveal the origin of the performance improvements. Our simple, inexpensive, and scalable electrode modification technique provides a significant step toward optimizing the device performance by engineering the semiconductor-electrode interfaces in OFETs.

  7. A Disposable paper breathalyzer with an alcohol sensing organic electrochemical transistor

    Science.gov (United States)

    Bihar, Eloїse; Deng, Yingxin; Miyake, Takeo; Saadaoui, Mohamed; Malliaras, George G.; Rolandi, Marco

    2016-06-01

    Breathalyzers estimate Blood Alcohol Content (BAC) from the concentration of ethanol in the breath. Breathalyzers are easy to use but are limited either by their high price and by environmental concerns, or by a short lifetime and the need for continuous recalibration. Here, we demonstrate a proof-of-concept disposable breathalyzer using an organic electrochemical transistor (OECT) modified with alcohol dehydrogenase (ADH) as the sensor. The OECT is made with the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and is printed on paper. ADH and its cofactor nicotinamide adenine dinucleotide (NAD+) are immobilized onto the OECT with an electrolyte gel. When the OECT-breathalyzer is exposed to ethanol vapor, the enzymatic reaction of ADH and ethanol transforms NAD+ into NADH, which causes a decrease in the OECT source drain current. In this fashion, the OECT-breathalyzer easily detects ethanol in the breath equivalent to BAC from 0.01% to 0.2%. The use of a printed OECT may contribute to the development of breathalyzers that are disposable, ecofriendly, and integrated with wearable devices for real-time BAC monitoring.

  8. Universal diffusion-limited injection and the hook effect in organic thin-film transistors.

    Science.gov (United States)

    Liu, Chuan; Huseynova, Gunel; Xu, Yong; Long, Dang Xuan; Park, Won-Tae; Liu, Xuying; Minari, Takeo; Noh, Yong-Young

    2016-01-01

    The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials. PMID:27440253

  9. A hybrid mask mould lithography scheme and its application in nanoscale organic thin film transistors

    Science.gov (United States)

    Cheng, Xing; Li, Dawen; Guo, L. Jay

    2006-02-01

    Nanoimprint lithography (NIL) has stimulated great interest in both academic research and industrial development due to its high resolution, high throughput and low cost advantages. Though NIL has been demonstrated to be very successful in replicating nanoscale features, it also has its limitations as a general lithography technique. Its fundamental moulding characteristics (i.e. physically displacing polymer materials) frequently lead to pattern defects when replicating arbitrary patterns, especially patterns with broad size distribution. To solve this problem, we have developed a combined nanoimprint and photolithography technique that uses a hybrid mould to achieve good pattern definitions. In this work, we applied this technique to fabricate finger-shaped nanoelectrodes, and demonstrated nanoscale pentacene organic thin film transistors (OTFTs). Methods of the hybrid mask-mould (HMM) fabrication and results on the device electrical characteristics are provided. With combined advantages of both photolithography and NIL, and the applicability to general nanoscale device and system fabrication, this method can become a valuable choice for low cost mass production of micro- and nanoscale structures, devices and systems.

  10. Liquid electrolyte positioning along the device channel influences the operation of Organic Electro-Chemical Transistors

    KAUST Repository

    D'angelo, Pasquale

    2014-11-01

    In this work, we show the influence of the liquid electrolyte adsorption by porous films made of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), PEDOT:PSS, on the operation of an Organic Electro-Chemical Transistor with an active channel based on these polymeric films. In particular, the effect of film hydration on device performance is evaluated by studying its electrical response as a function of the spatial position between the electrolyte and the channel electrodes. This is done by depositing a PEDOT:PSS film on a super-hydrophobic surface aimed at controlling the electrolyte confinement next to the electrodes. The device response shows that the confinement of ionic liquids near to the drain electrode results in a worsening of the current modulation. This result has been interpreted in the light of studies dealing with the transport of ions in semiconducting polymers, indicating that the electrolyte adsorption by the polymeric film implies the formation of liquid pathways inside its bulk. These pathways, in particular, affect the device response because they are able to assist the drift of ionic species in the electrolyte towards the drain electrode. The effect of electrolyte adsorption on the device operation is confirmed by means of moving-front measurements, and is related to the reproducibility of the device operation curves by measuring repeatedly its electrical response.

  11. Selective detection of dopamine with an all PEDOT:PSS Organic Electrochemical Transistor

    Science.gov (United States)

    Gualandi, Isacco; Tonelli, Domenica; Mariani, Federica; Scavetta, Erika; Marzocchi, Marco; Fraboni, Beatrice

    2016-10-01

    An all PEDOT:PSS Organic Electrochemical Transistor (OECT) has been developed and used for the selective detection of dopamine (DA) in the presence of interfering compounds (ascorbic acid, AA and uric acid, UA). The selective response has been implemented using a potentiodynamic approach, by varying the operating gate voltage and the scan rate. The trans-conductance curves allow to obtain a linear calibration plot for AA, UA and DA and to separate the redox waves associated to each compound; for this purpose, the scan rate is an important parameter to achieve a good resolution. The sensitivities and limits of detection obtained with the OECT have been compared with those obtained by potential step amperometric techniques (cyclic voltammetry and differential pulse voltammetry), employing a PEDOT:PSS working electrode: our results prove that the all-PEDOT:PSS OECT sensitivities and limits of detection are comparable or even better than those obtained by DPV, a technique that employs a sophisticate potential wave and read-out system in order to maximize the performance of electrochemical sensors and that can hardly be considered a viable readout method in practical applications.

  12. Universal diffusion-limited injection and the hook effect in organic thin-film transistors

    Science.gov (United States)

    Liu, Chuan; Huseynova, Gunel; Xu, Yong; Long, Dang Xuan; Park, Won-Tae; Liu, Xuying; Minari, Takeo; Noh, Yong-Young

    2016-07-01

    The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials.

  13. New Driving Scheme to Improve Hysteresis Characteristics of Organic Thin Film Transistor-Driven Active-Matrix Organic Light Emitting Diode Display

    Science.gov (United States)

    Yamamoto, Toshihiro; Nakajima, Yoshiki; Takei, Tatsuya; Fujisaki, Yoshihide; Fukagawa, Hirohiko; Suzuki, Mitsunori; Motomura, Genichi; Sato, Hiroto; Tokito, Shizuo; Fujikake, Hideo

    2011-02-01

    A new driving scheme for an active-matrix organic light emitting diode (AMOLED) display was developed to prevent the picture quality degradation caused by the hysteresis characteristics of organic thin film transistors (OTFTs). In this driving scheme, the gate electrode voltage of a driving-OTFT is directly controlled through the storage capacitor so that the operating point for the driving-OTFT is on the same hysteresis curve for every pixel after signal data are stored in the storage capacitor. Although the number of OTFTs in each pixel for the AMOLED display is restricted because OTFT size should be large enough to drive organic light emitting diodes (OLEDs) due to their small carrier mobility, it can improve the picture quality for an OTFT-driven flexible OLED display with the basic two transistor-one capacitor circuitry.

  14. Bistable organic materials in optoelectrical switches: Two-electrode devices vs. organic field effect transistors

    CERN Document Server

    Sworakowski, Juliusz

    2011-01-01

    The paper presents a short overview of research into properties of organic materials and structures that could be used in optoelectrical switches, i.e., switches in which changes in electrical properties are triggered by light of appropriate wavelengths. In particular, described are the structures acting by virtue of reversible photochemical reactions occurring in photochromic molecular materials.

  15. Lithography-free high-resolution inkjet-printed OFET (organic field effect transistor) fabrication on polymer by laser processing

    Science.gov (United States)

    Ko, Seung Hwan; Pan, Heng; Grigoropoulos, Costas P.; Poulikakos, Dimos

    2007-02-01

    The low temperature fabrication of OFET (organic field effect transistor) on the flexible polymer substrate is presented in this paper. A drop-on-demand (DOD) ink-jetting system was used to print gold nano-particles suspended in Alpha-Terpineol solvent, PVP (poly-4-vinylphenol) in PGMEA (propylene glycol monomethyl ether acetate) solvent, semiconductor polymer (modified polythiophene) in dichlorobenzene (o-DCB) solution to fabricate OFET on flexible polymer substrates. Short pulsed laser ablation enabled finer electrical components to overcome the resolution limitation of inkjet deposition. Continuous Argon ion laser was irradiated locally to evaporate carrier solvent as well as to sinter gold nano-particles. In addition, a new selective ablation of multilayered gold nanoparticle film was demonstrated using the SPLA-DAT (selective pulsed laser ablation by differential ablation threshold) scheme for sintered and non-sintered gold nanoparticles. Finally, selective ablation of multilayered film was used to define narrow channel of a FET (field effect transistor) and semiconductor polymer solution was deposited on top of channel to complete OFET (organic field effect transistor) fabrication.

  16. Novel self-assembled phosphonic acids monolayers applied in N-channel perylene diimide (PDI) organic field effect transistors

    Science.gov (United States)

    Cheng, Heng; Huai, Jinyue; Cao, Li; Li, Zhefeng

    2016-08-01

    Phosphoric acid (PA) self-assembled monolayers (SAMs) have been developed for applications in organic field-effect transistors (OFETs). This efficient interface modification is helpful for semiconductor layer to form crystal thin film during vapor deposition. Results show that the PDI-i8C based OFETs with PA SAMs exhibit field-effect mobilities up to 0.014 cm2 V-1 s-1 (with ODPA as SAMs), which is over 500 times higher than the device without SAMs. Also, transistors with Naph6PA as SAMs show up to 1.5 × 10-3 cm2 V-1 s-1. By studying the morphology of semiconductor layer and SAMs surface, it is found that ODPA bilayer structure plays a key role in inducing PDI-i8C to form orderly crystal thin film.

  17. Through thick and thin: tuning the threshold voltage in organic field-effect transistors.

    Science.gov (United States)

    Martínez Hardigree, Josué F; Katz, Howard E

    2014-04-15

    Organic semiconductors (OSCs) constitute a class of organic materials containing densely packed, overlapping conjugated molecular moieties that enable charge carrier transport. Their unique optical, electrical, and magnetic properties have been investigated for use in next-generation electronic devices, from roll-up displays and radiofrequency identification (RFID) to biological sensors. The organic field-effect transistor (OFET) is the key active element for many of these applications, but the high values, poor definition, and long-term instability of the threshold voltage (V(T)) in OFETs remain barriers to realization of their full potential because the power and control circuitry necessary to compensate for overvoltages and drifting set points decrease OFET practicality. The drifting phenomenon has been widely observed and generally termed "bias stress." Research on the mechanisms responsible for this poor V(T) control has revealed a strong dependence on the physical order and chemical makeup of the interfaces between OSCs and adjacent materials in the OFET architecture. In this Account, we review the state of the art for tuning OFET performance via chemical designs and physical processes that manipulate V(T). This parameter gets to the heart of OFET operation, as it determines the voltage regimes where OFETs are either ON or OFF, the basis for the logical function of the devices. One obvious way to decrease the magnitude and variability of V(T) is to work with thinner and higher permittivity gate dielectrics. From the perspective of interfacial engineering, we evaluate various methods that we and others have developed, from electrostatic poling of gate dielectrics to molecular design of substituted alkyl chains. Corona charging of dielectric surfaces, a method for charging the surface of an insulating material using a constant high-voltage field, is a brute force means of shifting the effective gate voltage applied to a gate dielectric. A gentler and more

  18. High-performance single crystal organic field-effect transistors based on two dithiophene-tetrathiafulvalene (DT-TTF) polymorphs.

    Science.gov (United States)

    Pfattner, Raphael; Mas-Torrent, Marta; Bilotti, Ivano; Brillante, Aldo; Milita, Silvia; Liscio, Fabiola; Biscarini, Fabio; Marszalek, Tomasz; Ulanski, Jacek; Nosal, Andrzej; Gazicki-Lipman, Maciej; Leufgen, Michael; Schmidt, Georg; Molenkamp, Laurens W; Laukhin, Vladimir; Veciana, Jaume; Rovira, Concepció

    2010-10-01

    Solution prepared single crystal organic field-effect transistors (OFETs) combine low-cost with high performance due to structural ordering of molecules. However, in organic crystals polymorphism is a known phenomenon, which can have a crucial influence on charge transport. Here, the performance of solution-prepared single crystal OFETs based on two different polymorphs of dithiophene-tetrathiafulvalene, which were investigated by confocal Raman spectroscopy and X-ray diffraction, are reported. OFET devices prepared using different configurations show that both polymorphs exhibited excellent device performance, although the -phase revealed charge carrier mobility between two and ten times higher in accordance to the closer stacking of the molecules.

  19. Effect of asymmetrical double-pockets and gate-drain underlap on Schottky barrier tunneling FET: Ambipolar conduction vs. high frequency performance

    Science.gov (United States)

    Shaker, Ahmed; Ossaimee, Mahmoud; Zekry, A.

    2016-08-01

    In this paper, a proposed structure based on asymmetrical double pockets SB-TFET with gate-drain underlap is presented. 2D extensive modeling and simulation, using Silvaco TCAD, were carried out to study the effect of both underlap length and pockets' doping on the transistor performance. It was found that the underlap from the drain side suppresses the ambipolar conduction and doesn't enhance the high-frequency characteristics. The enhancement of the high-frequency characteristics could be realized by increasing the doping of the drain pocket over the doping of the source pocket. An optimum choice was found which gives the conditions of minimum ambipolar conduction, maximum ON current and maximum cut-off frequency. These enhancements render the device more competitive as a nanometer transistor.

  20. Electrical characterization of graphene oxide and organic dielectric layers based on thin film transistor

    International Nuclear Information System (INIS)

    Highlights: • We report the synthesis of graphene oxide nanosheets and electrical characterization of graphene oxide based thin film transistor. • Graphene oxide (GO) nanosheets were prepared by using modified Hummers method. • We used insulator layers which are polymethylmethacrylate (PMMA) and polyvinyl phenol (PVP) for graphene oxide based thin flim transistor. - Abstract: We have studied the electrical characteristics of graphene oxide based thin flim transistor with the polymer insulators such as polymethyl methacrylate (PMMA) and poly-4-vinylphenol (PVP). Graphene oxide (GO) nanosheets were prepared by using modified Hummers method. The structural properties of GO nanosheets were characterized with Ultraviolet Visible (UV–vis), FT-IR spectroscopy and X-rays diffraction (XRD). Graphene oxide based thin flim transistor (GO-TFT) was prepared by a spin-coating and thermal evaporation technique. The electrical characterization of GO-TFT was analyzed by output and transfer characteristics by using Keithley-4200 semiconductor characterization system (SCS). The graphene oxide based thin flim transistor devices show p-type semiconducting behavior. The mobility, threshold voltage, sub-threshold swing value and Ion/Ioff of GO-TFT were found to be 0.105 cm2 V−1 s−1, −8.7 V, 4.03 V/decade and 10, respectively

  1. Multiscale sensing of antibody-antigen interactions by organic transistors and single-molecule force spectroscopy.

    Science.gov (United States)

    Casalini, Stefano; Dumitru, Andra C; Leonardi, Francesca; Bortolotti, Carlo A; Herruzo, Elena T; Campana, Alessandra; de Oliveira, Rafael F; Cramer, Tobias; Garcia, Ricardo; Biscarini, Fabio

    2015-05-26

    Antibody-antigen (Ab-Ag) recognition is the primary event at the basis of many biosensing platforms. In label-free biosensors, these events occurring at solid-liquid interfaces are complex and often difficult to control technologically across the smallest length scales down to the molecular scale. Here a molecular-scale technique, such as single-molecule force spectroscopy, is performed across areas of a real electrode functionalized for the immunodetection of an inflammatory cytokine, viz. interleukin-4 (IL4). The statistical analysis of force-distance curves allows us to quantify the probability, the characteristic length scales, the adhesion energy, and the time scales of specific recognition. These results enable us to rationalize the response of an electrolyte-gated organic field-effect transistor (EGOFET) operated as an IL4 immunosensor. Two different strategies for the immobilization of IL4 antibodies on the Au gate electrode have been compared: antibodies are bound to (i) a smooth film of His-tagged protein G (PG)/Au; (ii) a 6-aminohexanethiol (HSC6NH2) self-assembled monolayer on Au through glutaraldehyde. The most sensitive EGOFET (concentration minimum detection level down to 5 nM of IL4) is obtained with the first functionalization strategy. This result is correlated to the highest probability (30%) of specific binding events detected by force spectroscopy on Ab/PG/Au electrodes, compared to 10% probability on electrodes with the second functionalization. Specifically, this demonstrates that Ab/PG/Au yields the largest areal density of oriented antibodies available for recognition. More in general, this work shows that specific recognition events in multiscale biosensors can be assessed, quantified, and optimized by means of a nanoscale technique. PMID:25868724

  2. Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Chang Jin; Wan, Qing, E-mail: wanqing@nju.edu.cn, E-mail: yshi@nju.edu.cn [School of Electronic Science & Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhu, Li Qiang [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wan, Xiang; Shi, Yi, E-mail: wanqing@nju.edu.cn, E-mail: yshi@nju.edu.cn [School of Electronic Science & Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2016-01-25

    The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

  3. ADO-phosphonic acid self-assembled monolayer modified dielectrics for organic thin film transistors

    Science.gov (United States)

    Zhefeng, Li; Xianye, Luo

    2014-10-01

    This study explores a strategy of using the phosphonic acid derivative (11-((12-(anthracen-2-yl)dodecyl)oxy)-11-oxoundecyl) phosphonic acid (ADO-phosphonic acid) as self-assembled monolayers (SAMs) on a Si/SiO2 surface to induce the crystallization of rubrene in vacuum deposited thin film transistors, which showed a field-effect mobility as high as 0.18 cm2/(V·s). It is found that ADO-phosphonic acid SAMs play a unique role in modulating the morphology of rubrene to form a crystalline film in the thin-film transistors.

  4. Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

    Science.gov (United States)

    Wan, Chang Jin; Zhu, Li Qiang; Wan, Xiang; Shi, Yi; Wan, Qing

    2016-01-01

    The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

  5. Design and Simulation of a 6-Bit Successive-Approximation ADC Using Modeled Organic Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Huyen Thanh Pham

    2016-01-01

    Full Text Available We have demonstrated a method for using proper models of pentacene P-channel and fullerene N-channel thin-film transistors (TFTs in order to design and simulate organic integrated circuits. Initially, the transistors were fabricated, and we measured their main physical and electrical parameters. Then, these organic TFTs (OTFTs were modeled with support of an organic process design kit (OPDK added in Cadence. The key specifications of the modeled elements were extracted from measured data, whereas the fitting ones were elected to replicate experimental curves. The simulating process proves that frequency responses of the TFTs cover all biosignal frequency ranges; hence, it is reasonable to deploy the elements to design integrated circuits used in biomedical applications. Complying with complementary rules, the organic circuits work properly, including logic gates, flip-flops, comparators, and analog-to-digital converters (ADCs as well. The proposed successive-approximation-register (SAR ADC consumes a power of 883.7 µW and achieves an ENOB of 5.05 bits, a SNR of 32.17 dB at a supply voltage of 10 V, and a sampling frequency of about 2 KHz.

  6. Controlled tunnel-coupled ferromagnetic electrodes for spin injection in organic single-crystal transistors

    NARCIS (Netherlands)

    Naber, W. J. M.; Craciun, M. F.; Lemmens, J. H. J.; Arkenbout, A. H.; Palstra, T. T. M.; Morpurgo, A. F.; van der Wiel, W. G.

    2010-01-01

    We report on single-crystal rubrene. eld-effect transistors (FETs) with ferromagnetic Co electrodes, tunnel-coupled to the conduction channel via an Al(2)O(3) tunnel barrier. Magnetic and electronic characterization shows that the Al(2)O(3) film not only protects the Co from undesired oxidation, but

  7. Controlled tunnel-coupled ferromagnetic electrodes for spin injection in organic single-crystal transistors

    NARCIS (Netherlands)

    Naber, W.J.M.; Craciun, M.F.; Lemmens, J.H.J.; Arkenbout, A.H.; Palstra, T.T.M.; Morpurgo, A.F.; Wiel, van der W.G.

    2011-01-01

    We report on single-crystal rubrene field-effect transistors (FETs) with ferromagnetic Co electrodes, tunnel-coupled to the conduction channel via an Al2O3 tunnel barrier. Magnetic and electronic characterization shows that the Al2O3 film not only protects the Co from undesired oxidation, but also p

  8. The Organic Power Transistor: Roll-to-Roll Manufacture, Thermal Behavior, and Power Handling When Driving Printed Electronics

    DEFF Research Database (Denmark)

    Pastorelli, Francesco; Schmidt, Thomas Mikael; Hösel, Markus;

    2016-01-01

    We present flexible organic power transistors prepared by fast (20mmin1) roll-to-roll (R2R) flexographic printing[1] of the drain (D) and source (S) electrode structures directly on polyester foil. The devices have top gate architecture and were completed by spin coating or slot-die coating...... to drive large currents while handling the thermal aspects in operation together with other organic printed electronics technologies such as large area organic photovoltaics (OPV)[2] and large area electrochromic displays (EC).[3] We find especially that an elevated operational temperature is beneficial...... with respect to both transconductance and on/off ratio. We achieve high currents of up to 45mA at a temperature of 80 C with an on/ off ratio of 100 which is sufficient to drive large area organic electronics such as an EC device powered by OPV devices that we also demonstrate. Finally, we observe...

  9. Enhanced performance of C60 N-type organic field-effect transistors using a pentacene passivation layer

    Institute of Scientific and Technical Information of China (English)

    Liang Xiaoyu; Cheng Xiaoman; Du Boqun; Bai Xiao; Fan Jianfeng

    2013-01-01

    We investigated the properties of C6o-based organic field-effect transistors (OFETs) with a pentacene passivation layer inserted between the C60 active layer and the gate dielectric.After modification of the pentacene passivation layer,the performance of the devices was considerably improved compared to C60-based OFETs with only a PMMA dielectric.The peak field-effect mobility was up to 1.01 cm2/(V·s) and the on/off ratio shifted to 104.This result indicates that using a pentacene passivation layer is an effective way to improve the performance of N-type OFETs.

  10. Cyanoethyl cellulose-based nanocomposite dielectric for low-voltage, solution-processed organic field-effect transistors (OFETs)

    OpenAIRE

    S. Faraji, E. Danesh, D. J. Tate, M. L. Turner, L. A. Majewski

    2016-01-01

    Low voltage organic field-effect transistors (OFETs) using solution-processed cyanoethyl cellulose (CEC) and CEC-based nanocomposites as the gate dielectric are demonstrated. Barium strontium titanate (BST) nanoparticles are homogeneously dispersed in CEC to form the high-k (18.0 ± 0.2 at 1 kHz) nanocomposite insulator layer. The optimised p-channel DPPTTT OFETs with BST-CEC nanocomposite as the gate dielectric operate with minimal hysteresis, display field-effect mobilities in excess of 1 cm...

  11. Ultra-high mobility transparent organic thin film transistors grown by an off-centre spin-coating method

    Science.gov (United States)

    Yuan, Yongbo; Giri, Gaurav; Ayzner, Alexander L.; Zoombelt, Arjan P.; Mannsfeld, Stefan C. B.; Chen, Jihua; Nordlund, Dennis; Toney, Michael F.; Huang, Jinsong; Bao, Zhenan

    2014-01-01

    Organic semiconductors with higher carrier mobility and better transparency have been actively pursued for numerous applications, such as flat-panel display backplane and sensor arrays. The carrier mobility is an important figure of merit and is sensitively influenced by the crystallinity and the molecular arrangement in a crystal lattice. Here we describe the growth of a highly aligned meta-stable structure of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) from a blended solution of C8-BTBT and polystyrene by using a novel off-centre spin-coating method. Combined with a vertical phase separation of the blend, the highly aligned, meta-stable C8-BTBT films provide a significantly increased thin film transistor hole mobility up to 43 cm2 Vs-1 (25 cm2 Vs-1 on average), which is the highest value reported to date for all organic molecules. The resulting transistors show high transparency of >90% over the visible spectrum, indicating their potential for transparent, high-performance organic electronics.

  12. Fabrication of organic semiconducting materials and high-performance organic thin-film transistors based on electron-irradiated polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeok Moo

    2011-02-15

    It was discovered that non-luminescent polystyrene (PS) can be converted to luminescent materials whose color can be changed in a wide visible range by electron irradiation. After the analyses of electron-irradiated PS, it was found that polycyclic aromatic hydrocarbons are produced by the irradiation and these PAHs are the origin of the luminescence from the electron-irradiated polymer. Based on the finding, a straightforward approach to produce desired light-emitting nanoarchitectures and nanopatterns only by irradiating an electron beam to the polymer was presented. In particular, the top-down irradiation approach provides a powerful tool to fabricate a variety of interesting nanoarchitectures when combined with bottom-up approaches; PS nanostructures prepared by self-assembling techniques can be directly transformed to luminescent nanostructures by electron irradiation while keeping their pristine morphologies. Light-emitting materials are widely used for optical, photonic, chemical and biomedical devices and a rapid progress in the devices requires well-defined luminescent nanoarchitectures. The approach presented here will be useful for a wide range of research fields including optics, photonics, chemistry, and biologics. On the other hand, a very simple but effective approach to produce high-performance rubrene organic thin-film transistors (OTFTs) with characteristics better than amorphous silicon TFTs was presented. Only by an abrupt heating process, high-quality crystalline rubrene semiconductor thin films that have almost ideal structures for OTFTs are created. The produced crystalline thin films consist of highly ordered, uniaxially oriented single-crystalline grains with large average sizes and the grains are interconnected with one another to form continuous films over the whole dielectric surfaces. Such high-quality crystalline rubrene thin films are remarkably rapidly produced in just 30 sec through this approach. Moreover, the increase of carrier

  13. A solution processable fluorene-benzothiadiazole small molecule for n-type organic field-effect transistors

    Science.gov (United States)

    Mutkins, Karyn; Gui, Ke; Aljada, Muhsen; Schwenn, Paul E.; Namdas, Ebinazar B.; Burn, Paul L.; Meredith, Paul

    2011-04-01

    We report an n-type organic semiconductor [2-({7-(9,9-di-n-propyl-9H-fluoren-2-yl}benzo[c][1,2,5]thiadiazol-4-yl)methylene]malononitrile (herein referred to as K12) for use in organic field-effect transistors (OFETs). K12 can be processed by spin-coating from solution or by vacuum deposition, organizing into highly orientated microcrystalline structures at modest (75 °C) annealing temperatures. OFETs with n-octyltrichlorosilane or hexamethyldisilazane monolayers, or poly(propylene-co-1-butene) (PPCB) modified dielectric surfaces were prepared. The mobility, ON/OFF ratio, threshold voltage, and current hysteresis were found to be dependent on the thermal history of the film and surface onto which it was deposited. The highest OFET mobility achieved was 2.4×10-3 cm2/V s, for spin-coated films with a PPCB modified silicon dioxide dielectric.

  14. High performance In2O3 nanowire transistors using organic gate nanodielectrics

    Science.gov (United States)

    Ju, Sanghyun; Ishikawa, Fumiaki; Chen, Pochiang; Chang, Hsiao-Kang; Zhou, Chongwu; Ha, Young-geun; Liu, Jun; Facchetti, Antonio; Marks, Tobin J.; Janes, David B.

    2008-06-01

    We report the fabrication of high performance nanowire transistors (NWTs) using In2O3 nanowires as the active channel and a self-assembled nanodielectric (SAND) as the gate insulator. The SAND-based single In2O3 NWTs are controlled by individually addressed gate electrodes. These devices exhibit n-type transistor characteristics with an on-current of ˜25μA for a single In2O3 nanowire at 2.0Vds, 2.1Vgs, a subthreshold slope of 0.2V/decade, an on-off current ratio of 106, and a field-effect mobility of ˜1450cm2/Vs. These results demonstrate that SAND-based In2O3 NWTs are promising candidates for high performance nanoscale logic technologies.

  15. Charge density dependent two-channel conduction in organic electric double layer transistors (EDLTs).

    Science.gov (United States)

    Xie, Wei; Liu, Feilong; Shi, Sha; Ruden, P Paul; Frisbie, C Daniel

    2014-04-23

    A transport model based on hole-density-dependent trapping is proposed to explain the two unusual conductivity peaks at surface hole densities above 10(13) cm(-2) in rubrene electric double layer transistors (EDLTs). Hole transport in rubrene is described to occur via multiple percolation pathways, where conduction is dominated by transport in the free-site channel at low hole density, and in the trap-site channel at larger hole density. PMID:24496822

  16. Impact of the Capacitance of the Dielectric on the Contact Resistance of Organic Thin-Film Transistors

    Science.gov (United States)

    Zojer, K.; Zojer, E.; Fernandez, A. F.; Gruber, M.

    2015-10-01

    As the operation of organic thin-film transistors relies exclusively on injected charge carriers, the gate-induced field assumes a dual role: It is responsible for charge-carrier accumulation and, provided that an injection barrier at the contact-semiconductor interface is present, aids charge-carrier injection across this barrier. Besides the gate-source bias, the thickness of the insulator and its dielectric constant influence the gate field. Here, we explore the impact of the capacitance of the gate dielectric on the performance of organic thin-film transistors utilizing drift-diffusion-based simulations comprising a self-consistent consideration of injection. Upon varying the capacitance of the insulating layer, we observe a conceptually different behavior for top-contact and bottom-contact architectures. Top-contact devices possess a nearly constant contact voltage in the linear regime leading to an apparent mobility lowering. In strong contrast, bottom-contact architectures possess non-Ohmic contact resistances in the linear regime due to a contact voltage whose value depends strongly on both the gate-source bias and the capacitance. Counterintuitively, this is accompanied by a mobility being apparently unaffected by the substantial contact resistance. Additionally, threshold-voltage shifts appear due to gate-limited injection. The latter is particularly dominant in bottom-contact architectures, where the threshold voltages steeply increase with the thickness of the insulating layer.

  17. Low operating voltage n-channel organic field effect transistors using lithium fluoride/PMMA bilayer gate dielectric

    International Nuclear Information System (INIS)

    Highlights: • Alternative to chemically crosslinking of PMMA to achieve low leakage in provided. • Effect of LiF in reducing gate leakage through the OFET device is studied. • Effect of gate leakage on transistor performance has been investigated. • Low voltage operable and low temperature processed n-channel OFETs were fabricated. - Abstract: We report low temperature processed, low voltage operable n-channel organic field effect transistors (OFETs) using N,N′-Dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) organic semiconductor and poly(methylmethacrylate) (PMMA)/lithium fluoride (LiF) bilayer gate dielectric. We have studied the role of LiF buffer dielectric in effectively reducing the gate leakage through the device and thus obtaining superior performance in contrast to the single layer PMMA dielectric devices. The bilayer OFET devices had a low threshold voltage (Vt) of the order of 5.3 V. The typical values of saturation electron mobility (μs), on/off ratio and inverse sub-threshold slope (S) for the range of devices made were estimated to be 2.8 × 10−3 cm2/V s, 385, and 3.8 V/decade respectively. Our work thus provides a potential substitution for much complicated process of chemically crosslinking PMMA to achieve low leakage, high capacitance, and thus low operating voltage OFETs

  18. Investigation of ambipolar signature in SiGeOI homojunction tunnel FETs

    Science.gov (United States)

    Hutin, L.; Oeflein, R. P.; Borrel, J.; Martinie, S.; Tabone, C.; Le Royer, C.; Vinet, M.

    2016-01-01

    In this paper, we study the ambipolar tunneling signature from the output characteristics of TFETs featuring Si0.8Ge0.2 homojunctions, which we compare to those measured on conventional MOSFETs and Schottky Barrier FETs. The difference with the former is immediate since a single TFET can display a transistor effect under both pull-up (nTFET) and pull-down (pTFET) biasing conditions. This is however a property shared with SBFETs, in which injection occurs via tunneling through a single carrier Schottky Barrier instead of band-to-band tunneling. Without requiring quantitative considerations on the current levels or transfer characteristics, we find that simply performing the same dual ID-VDS electrical tests while voluntarily "swapping" the S/D terminals unequivocally characterizes TFET operation, even compared to asymmetrically doped SBFETs.

  19. Solution-processed small molecule-polymer blend organic thin-film transistors with hole mobility greater than 5 cm 2/Vs

    KAUST Repository

    Smith, Jeremy N.

    2012-04-10

    Using phase-separated organic semiconducting blends containing a small molecule, as the hole transporting material, and a conjugated amorphous polymer, as the binder material, we demonstrate solution-processed organic thin-film transistors with superior performance characteristics that include; hole mobility >5 cm 2/Vs, current on/off ratio ≥10 6 and narrow transistor parameter spread. These exceptional characteristics are attributed to the electronic properties of the binder polymer and the advantageous nanomorphology of the blend film. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Simulations of chromospheric heating by ambipolar diffusion

    CERN Document Server

    Khomenko, Elena

    2012-01-01

    We propose a mechanism for efficient heating of the solar chromosphere, based on non-ideal plasma effects. Three ingredients are needed for the work of this mechanism: (1) presence of neutral atoms; (2) presence of a non-potential magnetic field; (3) decrease of the collisional coupling of the plasma. Due to decrease of collisional coupling, a net relative motion appears between the neutral and ionized components, usually referred to as "ambipolar diffusion". This results in a significant enhancement of current dissipation as compared to the classical MHD case. We propose that the current dissipation in this situation is able to provide enough energy to heat the chromosphere by several kK on the time scale of minutes, or even seconds. In this paper, we show that this energy supply might be sufficient to balance the radiative energy losses of the chromosphere.

  1. Synthesis of Acenaphthyl and Phenanthrene Based Fused-Aromatic Thienopyrazine Co-Polymers for Photovoltaic and Thin Film Transistor Applications

    KAUST Repository

    Mondal, Rajib

    2009-08-11

    Dithiophene and fluorene co-polymers containing fused aromatic thieno[3,4-b]pyrazine moieties were synthesized for organic thin film transistor (OTFT) and organic photovoltaic (OPV) applications. Suzuki and Stille polycondensation reactions were used for the polymerization. The band gap (Eg) of the polymers was tuned in the range of 1.15-1.6 eV to match the solar spectrum. Density functional theory calculations were carried out to rationalize the low band gaps. These polymers showed field effect mobility (μ) as high as 0.2 cm2/(V.s) with an on/off ratio as high as 106 in OTFT devices. Interestingly, one polymer in this class also showed ambipolar charge transport. Power conversion efficiency (PCE) up to 1.3% was achieved in bulk heterojunction solar cells, indicating that these materials are promising for OPV applications. © 2009 American Chemical Society.

  2. The relationship between the reliability of transistors with 2D AlGaN/GaN channel and organization type of nanomaterial

    Science.gov (United States)

    Emtsev, V. V.; Zavarin, E. E.; Oganesyan, G. A.; Petrov, V. N.; Sakharov, A. V.; Shmidt, N. M.; V'yuginov, V. N.; Zybin, A. A.; Parnes, Ya. M.; Vidyakin, S. I.; Gudkov, A. G.; Chernyakov, A. E.

    2016-07-01

    The first experimental results demonstrating that the carrier mobility in the AlGaN/GaN 2D channel of transistor structures (AlGaN/GaN-HEMT) is correlated with the manner in which the nanomaterial is organized and also with the operation reliability of transistor parameters are presented. It is shown that improving the nature of organization of the nanomaterials in AlGaN/GaN-HEMT structures, evaluated by the multifractal parameter characterizing the extent to which a nanomaterial is disordered (local symmetry breaking) is accompanied by a significant, several-fold increase in the electron mobility in the 2D channel and in the reliability of parameters of transistors fabricated from these structures.

  3. Molecular reorganization in organic field-effect transistors and its effect on two-dimensional charge transport pathways.

    Science.gov (United States)

    Liscio, Fabiola; Albonetti, Cristiano; Broch, Katharina; Shehu, Arian; Quiroga, Santiago David; Ferlauto, Laura; Frank, Christian; Kowarik, Stefan; Nervo, Roberto; Gerlach, Alexander; Milita, Silvia; Schreiber, Frank; Biscarini, Fabio

    2013-02-26

    Charge transport in organic thin film transistors takes place in the first few molecular layers in contact with the gate dielectric. Here we demonstrate that the charge transport pathways in these devices are extremely sensitive to the orientational defects of the first monolayers, which arise from specific growth conditions. Although these defects partially heal during the growth, they cause depletion of charge carriers in the first monolayer, and drive the current to flow in the monolayers above the first one. Moreover, the residual defects induce lower crystalline order and charge mobility. These results, which are not intuitively explained by electrostatics arguments, have been obtained by combining in situ real time structural and electrical characterization together with ex situ AFM measurements, on thin films of a relevant n-type organic semiconductor, N,N'-bis(n-octyl)-dicyanoperylene-3,4:9,10-bis dicarboximide grown by sublimation in a quasi-layer-by-layer mode at different substrate temperatures.

  4. Highly sensitive NH3 detection based on organic field-effect transistors with tris(pentafluorophenyl)borane as receptor.

    Science.gov (United States)

    Huang, Weiguo; Besar, Kalpana; LeCover, Rachel; Rule, Ana María; Breysse, Patrick N; Katz, Howard E

    2012-09-12

    We have increased organic field-effect transistor (OFET) NH(3) response using tris(pentafluorophenyl)borane (TPFB) as a receptor. OFETs with this additive could detect concentrations of 450 ppb v/v, with a limit of detection of 350 ppb, the highest sensitivity reported to date for semiconductor films; in comparison, when triphenylmethane (TPM) or triphenylborane (TFB) was used as an additive, no obvious improvement in the sensitivity was observed. These OFETs also showed considerable selectivity with respect to common organic vapors and stability toward storage. Furthermore, excellent memory of exposure was achieved by keeping the exposed devices in a sealed container stored at -30 °C, the first such capability demonstrated with OFETs. PMID:22934620

  5. Large scale pattern graphene electrode for high performance in transparent organic single crystal field-effect transistors.

    Science.gov (United States)

    Liu, Wei; Jackson, Biyun Li; Zhu, Jing; Miao, Cong-Qin; Chung, Choong-Heui; Chung, Choon-Heui; Park, Young-Ju; Sun, Ke; Woo, Jason; Xie, Ya-Hong

    2010-07-27

    High quality, large grain size graphene on polycrystalline nickel film on two inch silicon wafers was successfully synthesized by the chemical vapor deposition (CVD) method. The polydimethylsiloxane (PDMS) stamping method was used for graphene transferring in this experiment. The graphene transferred onto Al2O3/ITO substrates was patterned into macroscopic dimension electrodes using conventional lithography followed by oxygen plasma etching. Experimental results show that this graphene can serve as transparent source and drain electrodes in high performance organic semiconductor nanoribbon organic field-effect transistors (OFETs), facilitating high hole injection efficiency due to the preferred work function match with the channel material: single crystalline copper phthalocyanine (CuPc) nanoribbons. The nanoribbons were grown on top of the patterned graphene via evaporate-deposition to form the FET device. The carrier mobility and on/off current ratio of such devices were measured to be as high as 0.36 cm2/(V s) and 10(4). PMID:20536162

  6. Electron Spin Resonance Study of Organic Interfaces in Ion Gel-Gated Rubrene Single-Crystal Transistors

    Science.gov (United States)

    Takahashi, Yuki; Tsuji, Masaki; Yomogida, Yohei; Takenobu, Taishi; Iwasa, Yoshihiro; Marumoto, Kazuhiro

    2013-04-01

    Organic interfaces of rubrene single crystals (RSCs) in ion gel-gated electric double-layer transistors (EDLTs) were investigated by electron spin resonance (ESR). The EDLTs were fabricated by laminating ion-gel films onto RSCs. Clear ESR signals due to field-injected holes in RSCs were successfully observed at low gate voltages, showing a high spin concentration due to the high capacitance of EDLTs. The analyses of anisotropic ESR signals and its gate-voltage dependence show that the bulk molecular orientation at RSCs' interfaces is preserved without forming deep trapping levels, which demonstrate that organic interfaces in RSC-EDLTs are clean and undamaged under a strong electric field in EDLTs.

  7. The relevance of ambipolar diffusion for neutron star evolution

    CERN Document Server

    Passamonti, Andrea; Pons, José A; Miralles, Juan A

    2016-01-01

    We study ambipolar diffusion in strongly magnetised neutron stars, with special focus on the effects of neutrino reaction rates and the impact of a superfluid/superconducting transition in the neutron star core. For axisymmetric magnetic field configurations, we determine the deviation from $\\beta-$equilibrium induced by the magnetic force and calculate the velocity of the slow, quasi-stationary, ambipolar drift. We study the temperature dependence of the velocity pattern and clearly identify the transition to a predominantly solenoidal flow. For stars without superconducting/superfluid constituents and with a mixed poloidal-toroidal magnetic field of typical magnetar strength, we find that ambipolar diffusion proceeds fast enough to have a significant impact on the magnetic field evolution only at low core temperatures, $T \\lesssim 1-2\\times10^8$ K. The ambipolar diffusion timescale becomes appreciably shorter when fast neutrino reactions are present, because the possibility to balance part of the magnetic f...

  8. Ultra-thin films of polysilsesquioxanes possessing 3-methacryloxypropyl groups as gate insulator for organic field-effect transistors

    International Nuclear Information System (INIS)

    Polysilsesquioxanes (PSQs) possessing 3-methacryloxypropyl groups as an organic moiety of the side chain were synthesized by sol–gel condensation copolymerization of the corresponding trialkoxysilanes. The ultra-thin PSQ film with a radical initiator and a cross-linking agent was prepared by a spin-coating method, and the film was cured integrally at low temperatures of less than 120 °C through two different kinds of polymeric reactions, which were radical polymerization of vinyl groups and sol–gel condensation polymerization of terminated silanol and alkoxy groups. The obtained PSQ film showed the almost perfect solubilization resistance to acetone, which is a good solvent of PSQ before polymerization. It became clear by atomic force microscopy observation that the surface of the PSQ film was very smooth at a nano-meter level. Furthermore, pentacene-based organic field-effect transistor (OFET) with the PSQ film as a gate insulator showed typical p-channel enhancement mode operation characteristics and therefore the ultra-thin PSQ film has the potential to be applicable for solution-processed OFET systems. - Highlights: ► Polysilsesquioxanes (PSQs) possessing 3-methacryloxypropyl groups were synthesized. ► The ultra-thin PSQ film could be cured at low temperatures of less than 120 °C. ► The PSQ film showed the almost perfect solubilization resistance to organic solvent. ► The surface of the PSQ film was very smooth at a nano-meter level. ► Pentacene-based organic field-effect transistor with the PSQ film was fabricated.

  9. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    OpenAIRE

    Ching-Lin Fan; Hao-Wei Chen; Hui-Lung Lai; Bo-Liang Guo; Bohr-Ran Huang

    2014-01-01

    This paper proposes a novel pixel circuit design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays that use low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) as driving element. The automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator was used to verify that the proposed pixel circuit, which comprises five transistors and one capacitor, can supply uniform output current. The v...

  10. Effects of bias stress on ZnO nanowire field-effect transistors fabricated with organic gate nanodielectrics

    Science.gov (United States)

    Ju, Sanghyun; Janes, David B.; Lu, Gang; Facchetti, Antonio; Marks, Tobin J.

    2006-11-01

    The effects of bias stress (gate stress or drain stress) on nanowire field-effect transistor (NW-FET) stability were investigated as a function of stress bias and stress time. The n-channel NW-FETs used a nanoscopic self-assembled organic gate insulator, and each device contained a single ZnO nanowire. Before stress, the off current is limited by a leakage current in the 1nA range, which increases as the gate to source bias becomes increasingly negative. The devices also exhibited significant changes in threshold voltage (Vth) and off current over 500 repeated measurement sweeps. The leakage current was significantly reduced after gate stress, but not after drain stress. Vth variations observed upon successive bias sweeps for devices following gate stress or drain stress were smaller than the Vth variation of unstressed devices. These observations suggest that gate stress and drain stress modify the ZnO nanowire-gate insulator interface, which can reduce electron trapping at the surface and therefore reduce the off current levels and variations in Vth. These results confirm that gate and drain stresses are effective means to stabilize device operation and provide high performance transistors with impressive reliabilities.

  11. A multi-agent quantum Monte Carlo model for charge transport: Application to organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Thilo; Jäger, Christof M. [Department of Chemistry and Pharmacy, Computer-Chemistry-Center and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen (Germany); Jordan, Meredith J. T. [School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia); Clark, Timothy, E-mail: tim.clark@fau.de [Department of Chemistry and Pharmacy, Computer-Chemistry-Center and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen (Germany); Centre for Molecular Design, University of Portsmouth, Portsmouth PO1 2DY (United Kingdom)

    2015-07-28

    We have developed a multi-agent quantum Monte Carlo model to describe the spatial dynamics of multiple majority charge carriers during conduction of electric current in the channel of organic field-effect transistors. The charge carriers are treated by a neglect of diatomic differential overlap Hamiltonian using a lattice of hydrogen-like basis functions. The local ionization energy and local electron affinity defined previously map the bulk structure of the transistor channel to external potentials for the simulations of electron- and hole-conduction, respectively. The model is designed without a specific charge-transport mechanism like hopping- or band-transport in mind and does not arbitrarily localize charge. An electrode model allows dynamic injection and depletion of charge carriers according to source-drain voltage. The field-effect is modeled by using the source-gate voltage in a Metropolis-like acceptance criterion. Although the current cannot be calculated because the simulations have no time axis, using the number of Monte Carlo moves as pseudo-time gives results that resemble experimental I/V curves.

  12. A multi-agent quantum Monte Carlo model for charge transport: Application to organic field-effect transistors

    International Nuclear Information System (INIS)

    We have developed a multi-agent quantum Monte Carlo model to describe the spatial dynamics of multiple majority charge carriers during conduction of electric current in the channel of organic field-effect transistors. The charge carriers are treated by a neglect of diatomic differential overlap Hamiltonian using a lattice of hydrogen-like basis functions. The local ionization energy and local electron affinity defined previously map the bulk structure of the transistor channel to external potentials for the simulations of electron- and hole-conduction, respectively. The model is designed without a specific charge-transport mechanism like hopping- or band-transport in mind and does not arbitrarily localize charge. An electrode model allows dynamic injection and depletion of charge carriers according to source-drain voltage. The field-effect is modeled by using the source-gate voltage in a Metropolis-like acceptance criterion. Although the current cannot be calculated because the simulations have no time axis, using the number of Monte Carlo moves as pseudo-time gives results that resemble experimental I/V curves

  13. Intrinsic graphene field effect transistor on amorphous carbon films

    OpenAIRE

    Tinchev, Savcho

    2013-01-01

    Fabrication of graphene field effect transistor is described which uses an intrinsic graphene on the surface of as deposited hydrogenated amorphous carbon films. Ambipolar characteristic has been demonstrated typical for graphene devices, which changes to unipolar characteristic if the surface graphene was etched in oxygen plasma. Because amorphous carbon films can be growth easily, with unlimited dimensions and no transfer of graphene is necessary, this can open new perspective for graphene ...

  14. Approaching the Trap-Free Limit in Organic Single-Crystal Field-Effect Transistors

    Science.gov (United States)

    Blülle, Balthasar; Häusermann, Roger; Batlogg, Bertram

    2014-04-01

    We present measurements of rubrene single-crystal field-effect transistors with textbooklike transfer characteristics, as one would expect for intrinsically trap-free semiconductor devices. Particularly, the high purity of the crystals and the defect-free interface to the gate dielectric are reflected in an unprecedentedly low subthreshold swing of 65 mV/decade, remarkably close to the fundamental limit of 58.5 mV/decade. From these measurements, we quantify the residual density of traps by a detailed analysis of the subthreshold regime, including a full numerical simulation. An exceedingly low trap density of Dbulk=1×1013 cm-3 eV-1 at an energy of approximately 0.62 eV is found. This result corresponds to one trap per eV in 108 rubrene molecules. The equivalent density of traps located at the interface (Dit=3×109 cm-2 eV-1) is as low as in the best crystalline Si/Si field-effect transistors. These results highlight the benefit of having van der Waals bonded semiconducting crystals without electronically active states due to broken bonds at the surface.

  15. Organic transistors fabricated by contact coating at liquid-solid interface for nano-structures

    Directory of Open Access Journals (Sweden)

    Yu-Wen Cheng

    2015-10-01

    Full Text Available A contact coating method is developed to cover the nano-channels with 100 nm or 200 nm diameter and 400 nm depth with a poly(4-vinylphenol (PVP. In such coating the nano-channels faces downwards and its vertical position is controlled by a motor. The surface is first lowered to be in immediate contact with the polyvinylpyrrolidone (PVPY water solution with concentration from 1 to 5 wt%, then pulled at the speed of 0.004 to 0.4 mm/s. By tuning the pulling speed and concentration we can realize conformal, filled, top-only, as well as floating film morphology. For a reproducible liquid detachment from the solid, the sample has a small tilt angle of 3 degree. Contact coating is used to cover the Al grid base of the vertical space-charge-limited transistor with PVPY. Poly(3-hexylthiophene-2,5-diyl (P3HT as the semiconductor. The transistor breakdown voltage is raised due to base coverage achieved by contact coating.

  16. Realization of size controllable graphene micro/nanogap with a micro/nanowire mask method for organic field-effect transistors

    DEFF Research Database (Denmark)

    Liao, Zhiyu; Wan, Qing; Liu, Huixuan;

    2011-01-01

    A size controllable graphene micro/nanogap fabrication method using micro/nanowire as mask is presented. The gap dimension can be adjusted by the diameter of the mask wire. As a typical application, copper phthalocyanine (CuPc) film organic field-effect transistors (OFETs) were fabricated...

  17. The effect of metal-buffer bilayer drain/source electrodes on the operational stability of the organic field effect transistors

    International Nuclear Information System (INIS)

    In this paper, we have investigated experimentally the effect of different drain/source (D/S) electrodes and charge injection buffer layers on the electrical properties and operational stability of a stilbene organic field effect transistor (OFET). The results show that the organic buffer layer of copper phthalocyanine (CuPc) considerably improves the electrical properties of the transistors, but has a negligible effect on their temporal behavior. On the other hand, inorganic metal-oxide buffer layer of molybdenum oxide (MoO3) drastically changes both the electrical properties and operational stability. The functionalities of this metal-oxide tightly depend on the properties of the D/S metallic electrodes. OFETs with Al/MoO3 as the bilayer D/S electrodes have the best electrical properties: field effect mobility μeff = 0.32 cm2 V−1 s−1 and threshold voltage VTH = − 5 V and the transistors with Ag/MoO3 have the longest operational stability. It was concluded that the chemical stability of the metal/metal-oxide or metal/organic interfaces of the bilayer D/S electrodes determine the operational stability of the OFETs. - Highlights: • The effect of buffer layers on the performance of the stilbene OFETs has been investigated. • Inorganic buffer layer improved the electrical and temporal behaviors simultaneously. • Organic buffer layer only changes the electrical properties. • Chemical stability of the interfaces determines the operational stability of the transistor

  18. Hydrogen ion-selective electrolyte-gated organic field-effect transistor for pH sensing

    Science.gov (United States)

    Kofler, Johannes; Schmoltner, Kerstin; Klug, Andreas; List-Kratochvil, Emil J. W.

    2014-05-01

    A H+ ion-selective electrolyte-gated organic field-effect transistor (IS-EGOFET) with a broad detection range between pH 3 and pH 12, is presented. This pH sensor relies on an integrated EGOFET used as a transducer in combination with an ionophore-doped polymeric ion-selective membrane serving as a sensing element. The broad detection range was possible through a dynamic measurement protocol comprising a readjustment of the gate voltage, which ensures a stable device operation at a constant working point. The effectiveness of this dynamic approach is confirmed by stability investigations. On the basis of this pH sensor concept, the importance of an appropriate gating electrolyte is highlighted, giving insights into the working mechanism of EGOFETs.

  19. High performance unipolar inverters by utilizing organic field-effect transistors with ultraviolet/ozone treated polystyrene dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wei; Yu, Xinge; Fan, Huidong; Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2014-09-01

    High performance unipolar inverters based on a significant variation of threshold voltage (V{sub th}) of organic field-effect transistors (OFETs), which was realized by introducing UV/ozone (UVO) treatment to polystyrene (PS) dielectric, were fabricated. A controllable V{sub th} shift of more than 10 V was obtained in the OFETs by adjusting the UVO treating time, and the unipolar inverters exhibited inverting voltage near 1/2 driving voltage and a noise margin of more than 70% of ideal value. From the analysis of scanning electron microscopy, atom force microscopy, and X-ray photoelectron spectroscopy, the dramatic controllable V{sub th} of OFETs, which played a key role in high performance unipolar inverters, was attributed to the newly generated oxygen functional groups in the PS dielectric induced by UVO treatment.

  20. Enhanced performance of C60 organic field effect transistors using a tris(8-hydroxyquinoline) aluminum buffer layer

    Institute of Scientific and Technical Information of China (English)

    Zheng Hong; Cheng Xiaoman; Tian Haijun; Zhao Geng

    2011-01-01

    We have investigated the properties of C60-based organic field effect transistors (OFETs) with a tris(8-hydroxyquinoline) aluminum (Alq3) buffer layer inserted between the source/drain electrodes and the active material.The electrical characteristics of OFETs are improved with the insertion of Aiq3 film.The peak field effect mobility is increased to 1.28 × 10-2 cm2/(V.s) and the threshold voltage is decreased to 10 V when the thickness of the Alq3 is 10 nm.The reason for the improved performance of the devices is probably due to the prevention of metal atoms diffusing into the C60 active layer and the reduction of the channel resistance in Alq3 films.

  1. Organic thin film transistors with a SiO2/SiNx/SiO2 composite insulator layer

    Institute of Scientific and Technical Information of China (English)

    Liu Xiang; Liu Hui

    2011-01-01

    We have investigated a SiO2/SiNx/SiO2 composite insulation layer structured gate dielectric for an organic thin film transistor (OTFT) with the purpose of improving the performance of the SiO2 gate insulator.The SiO2/SiNx/SiO2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO2 insulation layer device,the SiO2/SiNx/SiO2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decreased leakage current.Electrical parameters such as carrier mobility by field effect measurement have been calculated.The performances of different insulating layer devices have been studied,and the results demonstrate that when the insulation layer thickness increases,the off-state current decreases.

  2. Chemical potential shift in organic field-effect transistors identified by soft X-ray operando nano-spectroscopy

    Science.gov (United States)

    Nagamura, Naoka; Kitada, Yuta; Tsurumi, Junto; Matsui, Hiroyuki; Horiba, Koji; Honma, Itaru; Takeya, Jun; Oshima, Masaharu

    2015-06-01

    A chemical potential shift in an organic field effect transistor (OFET) during operation has been revealed by soft X-ray operando nano-spectroscopy analysis performed using a three-dimensional nanoscale electron-spectroscopy chemical analysis system. OFETs were fabricated using ultrathin (3 ML or 12 nm) single-crystalline C10-DNBDT-NW films on SiO2 (200 nm)/Si substrates with a backgate electrode and top source/drain Au electrodes, and C 1s line profiles under biasing at the backgate and drain electrodes were measured. When applying -30 V to the backgate, there is C 1s core level shift of 0.1 eV; this shift can be attributed to a chemical potential shift corresponding to band bending by the field effect, resulting in p-type doping.

  3. Chemical potential shift in organic field-effect transistors identified by soft X-ray operando nano-spectroscopy

    International Nuclear Information System (INIS)

    A chemical potential shift in an organic field effect transistor (OFET) during operation has been revealed by soft X-ray operando nano-spectroscopy analysis performed using a three-dimensional nanoscale electron-spectroscopy chemical analysis system. OFETs were fabricated using ultrathin (3 ML or 12 nm) single-crystalline C10-DNBDT-NW films on SiO2 (200 nm)/Si substrates with a backgate electrode and top source/drain Au electrodes, and C 1s line profiles under biasing at the backgate and drain electrodes were measured. When applying −30 V to the backgate, there is C 1s core level shift of 0.1 eV; this shift can be attributed to a chemical potential shift corresponding to band bending by the field effect, resulting in p-type doping

  4. Chemical potential shift in organic field-effect transistors identified by soft X-ray operando nano-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nagamura, Naoka, E-mail: NAGAMURA.Naoka@nims.go.jp; Kitada, Yuta; Honma, Itaru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tsurumi, Junto; Matsui, Hiroyuki; Takeya, Jun [Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Horiba, Koji [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Oshima, Masaharu [Synchrotron Radiation Research Organization, The University of Tokyo, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)

    2015-06-22

    A chemical potential shift in an organic field effect transistor (OFET) during operation has been revealed by soft X-ray operando nano-spectroscopy analysis performed using a three-dimensional nanoscale electron-spectroscopy chemical analysis system. OFETs were fabricated using ultrathin (3 ML or 12 nm) single-crystalline C10-DNBDT-NW films on SiO{sub 2} (200 nm)/Si substrates with a backgate electrode and top source/drain Au electrodes, and C 1s line profiles under biasing at the backgate and drain electrodes were measured. When applying −30 V to the backgate, there is C 1s core level shift of 0.1 eV; this shift can be attributed to a chemical potential shift corresponding to band bending by the field effect, resulting in p-type doping.

  5. A Label-Free Immunosensor for IgG Based on an Extended-Gate Type Organic Field Effect Transistor

    Directory of Open Access Journals (Sweden)

    Tsukuru Minamiki

    2014-09-01

    Full Text Available A novel biosensor for immunoglobulin G (IgG detection based on an extended-gate type organic field effect transistor (OFET has been developed that possesses an anti-IgG antibody on its extended-gate electrode and can be operated below 3 V. The titration results from the target IgG in the presence of a bovine serum albumin interferent, clearly exhibiting a negative shift in the OFET transfer curve with increasing IgG concentration. This is presumed to be due an interaction between target IgG and the immobilized anti-IgG antibody on the extended-gate electrode. As a result, a linear range from 0 to 10 µg/mL was achieved with a relatively low detection limit of 0.62 µg/mL (=4 nM. We believe that these results open up opportunities for applying extended-gate-type OFETs to immunosensing.

  6. Performance enhancement of pentacene-based organic field-effect transistor by inserting a WO3 buffer layer

    International Nuclear Information System (INIS)

    The pentacene-based organic field effect transistor (OFET) with a thin transition metal oxide (WO3) layer between pentacene and metal (Al) source/drain electrodes was fabricated. Compared with conventional OFET with only metal Al source/drain electrodes, the introduction of the WO3 buffer layer leads to the device performance enhancement. The effective field-effect mobility and threshold voltage are improved to 1.90 cm2/(V·s) and 13 V, respectively. The performance improvements are attributed to the decrease of the interface energy barrier and the contact resistance. The results indicate that it is an effective approach to improve the OFET performance by using a WO3 buffer layer. (semiconductor devices)

  7. A New Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuit for Active Matrix Organic Light Emitting Diode

    Science.gov (United States)

    Fan, Ching-Lin; Lin, Yi-Yan; Chang, Jyu-Yu; Sun, Bo-Jhang; Liu, Yan-Wei

    2010-06-01

    This study presents one novel compensation pixel design and driving method for active matrix organic light-emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage feed-back method and the simulation results are proposed and verified by SPICE simulator. The measurement and simulation of LTPS TFT characteristics demonstrate the good fitting result. The proposed circuit consists of four TFTs and two capacitors with an additional signal line. The error rates of OLED anode voltage variation are below 0.3% under the threshold voltage deviation of driving TFT (ΔVTH = ±0.33 V). The simulation results show that the pixel design can improve the display image non-uniformity by compensating the threshold voltage deviation of driving TFT and the degradation of OLED threshold voltage at the same time.

  8. Enhanced electrical properties of pentacene-based organic thin-film transistors by modifying the gate insulator surface

    Science.gov (United States)

    Tang, J. X.; Lee, C. S.; Chan, M. Y.; Lee, S. T.

    2008-09-01

    A reliable surface treatment for the pentacene/gate dielectric interface was developed to enhance the electrical transport properties of organic thin-film transistors (OTFTs). Plasma-polymerized fluorocarbon (CFx) film was deposited onto the SiO 2 gate dielectric prior to pentacene deposition, resulting in a dramatic increase of the field-effect mobility from 0.015 cm 2/(V s) to 0.22 cm 2/(V s), and a threshold voltage reduction from -14.0 V to -9.9 V. The observed carrier mobility increase by a factor of 10 in the resulting OTFTs is associated with various growth behaviors of polycrystalline pentacene thin films on different substrates, where a pronounced morphological change occurs in the first few molecular layers but the similar morphologies in the upper layers. The accompanying threshold voltage variation suggests that hole accumulation in the conduction channel-induced weak charge transfer between pentacene and CFx.

  9. Drain Voltage Scaling in Carbon Nanotube Transistors

    OpenAIRE

    Radosavljevic, M.; Heinze, S.; Tersoff, J.; Avouris, Ph.

    2003-01-01

    While decreasing the oxide thickness in carbon nanotube field-effect transistors (CNFETs) improves the turn-on behavior, we demonstrate that this also requires scaling the range of the drain voltage. This scaling is needed to avoid an exponential increase in Off-current with drain voltage, due to modulation of the Schottky barriers at both the source and drain contact. We illustrate this with results for bottom-gated ambipolar CNFETs with oxides of 2 and 5 nm, and give an explicit scaling rul...

  10. Photoconductive and supramolecularly engineered organic field-effect transistors based on fibres from donor-acceptor dyads

    Science.gov (United States)

    Treier, Matthias; Liscio, Andrea; Mativetsky, Jeffrey M.; Kastler, Marcel; Müllen, Klaus; Palermo, Vincenzo; Samorì, Paolo

    2012-02-01

    We report on the formation of photoconductive self-assembled fibres by solvent induced precipitation of a HBC-PMI donor-acceptor dyad. Kelvin Probe Force Microscopy revealed that upon illumination with white light the surface potential of the fibres shifted to negative values due to a build-up of negative charge. When integrated in a field-effect transistor (FET) configuration, the devices can be turned `on' much more efficiently using light than conventional bias triggered field-effect, suggesting that these structures could be used for the fabrication of light sensing devices. Such a double gating represents an important step towards bi-functional organic FETs, in which the current through the junction can be modulated both optically (by photoexcitation) and electrically (by gate control).We report on the formation of photoconductive self-assembled fibres by solvent induced precipitation of a HBC-PMI donor-acceptor dyad. Kelvin Probe Force Microscopy revealed that upon illumination with white light the surface potential of the fibres shifted to negative values due to a build-up of negative charge. When integrated in a field-effect transistor (FET) configuration, the devices can be turned `on' much more efficiently using light than conventional bias triggered field-effect, suggesting that these structures could be used for the fabrication of light sensing devices. Such a double gating represents an important step towards bi-functional organic FETs, in which the current through the junction can be modulated both optically (by photoexcitation) and electrically (by gate control). Electronic supplementary information (ESI) available: Experimental details and photoresponse on spin-coated film (3 pages). See DOI: 10.1039/c2nr11635a

  11. Dianthraceno[a,e]pentalenes: Synthesis, crystallographic structures and applications in organic field-effect transistors

    KAUST Repository

    Dai, Gaole

    2015-01-01

    Two soluble and stable dianthraceno[a,e]pentalenes with two (DAP1) and six (DAP2) phenyl substituents were synthesized. Both compounds possess a small energy band gap and show amphoteric redox behaviour due to intramolecular donor-accepter interactions. X-ray crystallographic analysis revealed that DAP2 has a closely packed structure with multi-dimensional [C-H⋯π] interactions although there are no π-π interactions between the dianthraceno[a,e]pentalene cores. As a result, solution-processed field effect transistors based on DAP2 exhibited an average hole mobility of 0.65 cm2 V-1 s-1. Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm2 V-1 s-1. This journal is

  12. Ambipolar solution-processed hybrid perovskite phototransistors

    KAUST Repository

    Li, Feng

    2015-09-08

    Organolead halide perovskites have attracted substantial attention because of their excellent physical properties, which enable them to serve as the active material in emerging hybrid solid-state solar cells. Here we investigate the phototransistors based on hybrid perovskite films and provide direct evidence for their superior carrier transport property with ambipolar characteristics. The field-effect mobilities for triiodide perovskites at room temperature are measured as 0.18 (0.17) cm2 V−1 s−1 for holes (electrons), which increase to 1.24 (1.01) cm2 V−1 s−1 for mixed-halide perovskites. The photoresponsivity of our hybrid perovskite devices reaches 320 A W−1, which is among the largest values reported for phototransistors. Importantly, the phototransistors exhibit an ultrafast photoresponse speed of less than 10 μs. The solution-based process and excellent device performance strongly underscore hybrid perovskites as promising material candidates for photoelectronic applications.

  13. Structure-performance correlations in vapor phase deposited self-assembled nanodielectrics for organic field-effect transistors.

    Science.gov (United States)

    DiBenedetto, Sara A; Frattarelli, David L; Facchetti, Antonio; Ratner, Mark A; Marks, Tobin J

    2009-08-12

    Organic field-effect transistor (OFETs) are fabricated using thin, vapor-deposited films of both the gate dielectric (vapor-deposited self-assembled nanodielectric, v-SAND) and the organic semiconductor. The nanoscopic self-assembled gate dielectrics are structurally organized via molecular precursor hydrogen-bonding interactions, followed by planarization with a vapor-deposited inorganic SiO(x) film. It is shown here that the metal-insulator-semiconductor (MIS) and OFET device electrical properties are sensitive to the v-SAND molecular dipolar orientation. In addition, alternating (organic/inorganic/organic/...) and nonalternating (1 organic layer + 1 inorganic layer) v-SAND microstructural arrangements are investigated, and the microstructures are correlated with MIS and OFET device characteristics. Films with alternating microstructures have larger capacitances than nonalternating films of the same thickness. However, they also have larger leakage currents, associated with the enhanced polarization of well-ordered dipolar films. For pentacene OFETs, the largest mobilities (approximately 3 cm(2)/(V s)) are associated with the high-capacitance nonalternating microstructure, and the lowest mobilities (approximately 0.5 cm(2)/(V s)) are associated with the alternating microstructure. v-SAND gated ambient-stable, n-type organic semiconductors show the opposite trends, where slightly greater OFET performance is observed with the lower-capacitance gate dielectric. For the p-type and one of the n-type v-SAND-based OFETs, the performance (under vacuum and ambient) is comparable to, or surpasses, that of previously reported devices using conventional SiO(2) as the gate dielectric. More importantly, the devices fabricated here operate at far lower voltages. These results indicate that v-SAND dielectrics are promising for future flexible organic electronics requiring low-temperature, solvent-free deposition conditions.

  14. High performance organic field-effect transistors with ultra-thin HfO{sub 2} gate insulator deposited directly onto the organic semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Ono, S., E-mail: shimpei@criepi.denken.or.jp [Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511 (Japan); Häusermann, R. [Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511 (Japan); Laboratory for Solid State Physics, ETH Zurich, Zurich 8093 (Switzerland); Chiba, D. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 322-0012 (Japan); Department of Applied Physics, University of Tokyo, Tokyo 113-8656 (Japan); Shimamura, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Batlogg, B. [Laboratory for Solid State Physics, ETH Zurich, Zurich 8093 (Switzerland)

    2014-01-06

    We have produced stable organic field-effect transistors (OFETs) with an ultra-thin HfO{sub 2} gate insulator deposited directly on top of rubrene single crystals by atomic layer deposition (ALD). We find that ALD is a gentle deposition process to grow thin films without damaging rubrene single crystals, as results these devices have a negligibly small threshold voltage and are very stable against gate-bias-stress, and the mobility exceeds 1 cm{sup 2}/V s. Moreover, the devices show very little degradation even when kept in air for more than 2 months. These results demonstrate thin HfO{sub 2} layers deposited by ALD to be well suited as high capacitance gate dielectrics in OFETs operating at small gate voltage. In addition, the dielectric layer acts as an effective passivation layer to protect the organic semiconductor.

  15. High performance organic field-effect transistors with ultra-thin HfO2 gate insulator deposited directly onto the organic semiconductor

    Science.gov (United States)

    Ono, S.; Häusermann, R.; Chiba, D.; Shimamura, K.; Ono, T.; Batlogg, B.

    2014-01-01

    We have produced stable organic field-effect transistors (OFETs) with an ultra-thin HfO2 gate insulator deposited directly on top of rubrene single crystals by atomic layer deposition (ALD). We find that ALD is a gentle deposition process to grow thin films without damaging rubrene single crystals, as results these devices have a negligibly small threshold voltage and are very stable against gate-bias-stress, and the mobility exceeds 1 cm2/V s. Moreover, the devices show very little degradation even when kept in air for more than 2 months. These results demonstrate thin HfO2 layers deposited by ALD to be well suited as high capacitance gate dielectrics in OFETs operating at small gate voltage. In addition, the dielectric layer acts as an effective passivation layer to protect the organic semiconductor.

  16. Electron Mobility Exceeding 10 cm(2) V(-1) s(-1) and Band-Like Charge Transport in Solution-Processed n-Channel Organic Thin-Film Transistors.

    Science.gov (United States)

    Xu, Xiaomin; Yao, Yifan; Shan, Bowen; Gu, Xiao; Liu, Danqing; Liu, Jinyu; Xu, Jianbin; Zhao, Ni; Hu, Wenping; Miao, Qian

    2016-07-01

    Solution-processed n-channel organic thin-film transistors (OTFTs) that exhibit a field-effect mobility as high as 11 cm(2) V(-1) s(-1) at room temperature and a band-like temperature dependence of electron mobility are reported. By comparison of solution-processed OTFTs with vacuum-deposited OTFTs of the same organic semiconductor, it is found that grain boundaries are a key factor inhibiting band-like charge transport. PMID:27151777

  17. Effect of titanium oxide-polystyrene nanocomposite dielectrics on morphology and thin film transistor performance for organic and polymeric semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Della Pelle, Andrea M. [LGS Innovations, 15 Vreeland Rd., Florham Park, NJ 07932 (United States); Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St. Amherst, MA 01003 (United States); Maliakal, Ashok, E-mail: maliakal@lgsinnovations.com [LGS Innovations, 15 Vreeland Rd., Florham Park, NJ 07932 (United States); Sidorenko, Alexander [Department of Chemistry and Biochemistry, University of the Sciences, 600 South 43rd St., Philadelphia, PA 191034 (United States); Thayumanavan, S. [Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St. Amherst, MA 01003 (United States)

    2012-07-31

    Previous studies have shown that organic thin film transistors with pentacene deposited on gate dielectrics composed of a blend of high K titanium oxide-polystyrene core-shell nanocomposite (TiO{sub 2}-PS) with polystyrene (PS) perform with an order of magnitude increase in saturation mobility for TiO{sub 2}-PS (K = 8) as compared to PS devices (K = 2.5). The current study finds that this performance enhancement can be translated to alternative small single crystal organics such as {alpha}-sexithiophene ({alpha}-6T) (enhancement factor for field effect mobility ranging from 30-100 Multiplication-Sign higher on TiO{sub 2}-PS/PS blended dielectrics as compared to homogenous PS dielectrics). Interestingly however, in the case of semicrystalline polymers such as (poly-3-hexylthiophene) P3HT, this dramatic enhancement is not observed, possibly due to the difference in processing conditions used to fabricate these devices (film transfer as opposed to thermal evaporation). The morphology for {alpha}-sexithiophene ({alpha}-6T) grown by thermal evaporation on TiO{sub 2}-PS/PS blended dielectrics parallels that observed in pentacene devices. Smaller grain size is observed for films grown on dielectrics with higher TiO{sub 2}-PS content. In the case of poly(3-hexylthiophene) (P3HT) devices, constructed via film transfer, morphological differences exist for the P3HT on different substrates, as discerned by atomic force microscopy studies. However, these devices only exhibit a modest (2 Multiplication-Sign ) increase in mobility with increasing TiO{sub 2}-PS content in the films. After annealing of the transferred P3HT thin film transistor (TFT) devices, no appreciable enhancement in mobility is observed across the different blended dielectrics. Overall the results support the hypothesis that nucleation rate is responsible for changes in film morphology and device performance in thermally evaporated small molecule crystalline organic semiconductor TFTs. The increased nucleation

  18. Effect of titanium oxide–polystyrene nanocomposite dielectrics on morphology and thin film transistor performance for organic and polymeric semiconductors

    International Nuclear Information System (INIS)

    Previous studies have shown that organic thin film transistors with pentacene deposited on gate dielectrics composed of a blend of high K titanium oxide–polystyrene core–shell nanocomposite (TiO2–PS) with polystyrene (PS) perform with an order of magnitude increase in saturation mobility for TiO2–PS (K = 8) as compared to PS devices (K = 2.5). The current study finds that this performance enhancement can be translated to alternative small single crystal organics such as α-sexithiophene (α-6T) (enhancement factor for field effect mobility ranging from 30-100× higher on TiO2–PS/PS blended dielectrics as compared to homogenous PS dielectrics). Interestingly however, in the case of semicrystalline polymers such as (poly-3-hexylthiophene) P3HT, this dramatic enhancement is not observed, possibly due to the difference in processing conditions used to fabricate these devices (film transfer as opposed to thermal evaporation). The morphology for α-sexithiophene (α-6T) grown by thermal evaporation on TiO2–PS/PS blended dielectrics parallels that observed in pentacene devices. Smaller grain size is observed for films grown on dielectrics with higher TiO2–PS content. In the case of poly(3-hexylthiophene) (P3HT) devices, constructed via film transfer, morphological differences exist for the P3HT on different substrates, as discerned by atomic force microscopy studies. However, these devices only exhibit a modest (2×) increase in mobility with increasing TiO2–PS content in the films. After annealing of the transferred P3HT thin film transistor (TFT) devices, no appreciable enhancement in mobility is observed across the different blended dielectrics. Overall the results support the hypothesis that nucleation rate is responsible for changes in film morphology and device performance in thermally evaporated small molecule crystalline organic semiconductor TFTs. The increased nucleation rate produces organic polycrystalline films with small grain size which are

  19. Isoindigo-Based Small Molecules with Varied Donor Components for Solution-Processable Organic Field Effect Transistor Devices.

    Science.gov (United States)

    Patil, Hemlata; Chang, Jingjing; Gupta, Akhil; Bilic, Ante; Wu, Jishan; Sonar, Prashant; Bhosale, Sheshanath V

    2015-09-18

    Two solution-processable small organic molecules, (E)-6,6'-bis(4-(diphenylamino)phenyl)-1,1'-bis(2-ethylhexyl)-(3,3'-biindolinylidene)-2,2'-dione (coded as S10) and (E)-6,6'-di(9H-carbazol-9-yl)-1,1'-bis(2-ethylhexyl)-(3,3'-biindolinylidene)-2,2'-dione (coded as S11) were successfully designed, synthesized and fully characterized. S10 and S11 are based on a donor-acceptor-donor structural motif and contain a common electron accepting moiety, isoindigo, along with different electron donating functionalities, triphenylamine and carbazole, respectively. Ultraviolet-visible absorption spectra revealed that the use of triphenylamine donor functionality resulted in an enhanced intramolecular charge transfer transition and reduction of optical band gap, when compared with its carbazole analogue. Both of these materials were designed to be donor semiconducting components, exerted excellent solubility in common organic solvents, showed excellent thermal stability, and their promising optoelectronic properties encouraged us to scrutinize charge-carrier mobilities using solution-processable organic field effect transistors. Hole mobilities of the order of 2.2 × 10(-4) cm²/Vs and 7.8 × 10(-3) cm²/Vs were measured using S10 and S11 as active materials, respectively.

  20. Enhanced mobility in organic field-effect transistors due to semiconductor/dielectric interface control and very thin single crystal

    Science.gov (United States)

    Dong, Ji; Yu, Peng; Atika Arabi, Syeda; Wang, Jiawei; He, Jun; Jiang, Chao

    2016-07-01

    A perfect organic crystal while keeping high quality semiconductor/dielectric interface with minimal defects and disorder is crucial for the realization of high performance organic single crystal field-effect transistors (OSCFETs). However, in most reported OSCFET devices, the crystal transfer processes is extensively used. Therefore, the semiconductor/dielectric interface is inevitably damaged. Carrier traps and scattering centers are brought into the conduction channel, so that the intrinsic high mobility of OSCFET devices is entirely disguised. Here, very thin pentacene single crystal is grown directly on bare SiO2 by developing a ‘seed-controlled’ pentacene single crystal method. The interface quality is controlled by an in situ fabrication of OSCFETs. The interface is kept intact without any transfer process. Furthermore, we quantitatively analyze the influence of crystal thickness on device performance. With a pristine interface and very thin crystal, we have achieved the highest mobility: 5.7 cm2 V‑1 s‑1—more than twice the highest ever reported pentacene OSCFET mobility on bare SiO2. This study may provide a universal route for the use of small organic molecules to achieve high performance in lamellar single crystal field-effect devices.

  1. Dependence of mobility on shallow localized gap states in single-crystal organic field-effect-transistors

    Energy Technology Data Exchange (ETDEWEB)

    Butko, V.Y., E-mail: vladimirybutko@gmail.co [Ioffe Physical Technical Institute, Polytechicheskaia 26, St. Petersburg 194021 (Russian Federation); So, W.; Lang, D.V. [Columbia University, New York, NY, 10027 (United States); Chi, X. [Texas A and M University-Kingsville (United States); Lashley, J.C. [Los Alamos National Laboratory (United States); Ramirez, A.P. [University of California Santa Cruz (United States)

    2009-12-15

    In order to optimize the performance of molecular organic electronic devices it is important to study the intermolecular density of states and charge transport mechanisms in the environment of crystalline organic material. Using this approach in Field Effect Transistors (FETs) we show that material purification improves carrier mobility and decreases density of the deep localized electronic state. We also report a general exponential energy dependence of the density of localized states in a vicinity of the mobility edge (Fermi energies up to approx7 times higher than the thermal energy (kT)) in a variety of the extensively purified molecular organic crystal FETs. This observation and the low activation energy of the order of approxkT suggest that molecular structural misplacements of the sizes that are comparable with thermal molecular modes rather than impurity deep traps play a role in formation of these shallow states. We find that the charge carrier mobility in the FET nanochannels, mu{sub eff}, is parameterized by two factors, the free-carrier mobility, mu{sub 0}, and the ratio of the free carrier density to the total carrier density induced by gate bias. Crystalline FETs fabricated from rubrene, pentacene, and tetracene have a high free-carrier mobility, mu{sub 0}approx50 cm{sup 2}/Vs, at 300 K with lower device mu{sub eff} dominated by localized shallow gap states. This relationship suggests that further improvements in electronic performance could be possible with enhanced device quality.

  2. Fabrication and characterization of p+-i-p+ type organic thin film transistors with electrodes of highly doped polymer

    Science.gov (United States)

    Tadaki, Daisuke; Ma, Teng; Zhang, Jinyu; Iino, Shohei; Hirano-Iwata, Ayumi; Kimura, Yasuo; Rosenberg, Richard A.; Niwano, Michio

    2016-04-01

    Organic thin film transistors (OTFTs) have been explored because of their advantageous features such as light-weight, flexible, and large-area. For more practical application of organic electronic devices, it is very important to realize OTFTs that are composed only of organic materials. In this paper, we have fabricated p+-i-p+ type of OTFTs in which an intrinsic (i) regioregular poly (3-hexylthiophene) (P3HT) layer is used as the active layer and highly doped p-type (p+) P3HT is used as the source and drain electrodes. The 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) was used as the p-type dopant. A fabricating method of p+-i-p+ OTFTs has been developed by using SiO2 and aluminum films as capping layers for micro-scaled patterning of the p+-P3HT electrodes. The characteristics of the OTFTs were examined using the photoelectron spectroscopy and electrical measurements. We demonstrated that the fabricated p+-i-p+ OTFTs work with carrier injection through a built-in potential at p+/i interfaces. We found that the p+-i-p+ OTFTs exhibit better FET characteristics than the conventional P3HT-OTFT with metal (Au) electrodes, indicating that the influence of a carrier injection barrier at the interface between the electrode and the active layer was suppressed by replacing the metal electrodes with p+-P3HT layers.

  3. Study on Preparation of High-k Organic-Inorganic Thin Film for Organic-Inorganic Thin Film Transistor Gate Dielectric Application

    Science.gov (United States)

    Lee, Wen-Hsi; Liu, Chao-Te; Lee, Ying-Chieh

    2012-06-01

    A simple solution-based deposition technique combined with spin-coating is a plausible way to prepare ultra-thin organic-inorganic nanocomposite films. In this study, we describe the spin-coating deposition of a colloidal nanoparticle suspension to obtain an ultra-thin organic-inorganic composite film as a gate insulator for organic thin film transistor (O-TFT) application. To obtain a homogenous organic-inorganic composite film, well-dispersed TiO2 nanoparticles in γ-butyrolactone and polyimide are important; therefore, several dispersants were assessed on the basis of the measurement of the rheological behavior of slurries. The thickness of the organic-inorganic composite film is mainly determined by the speed of spin-coating and viscosity of slurries. An approximately 4000-Å-thick nanocomposite film with homogeneous distribution of TiO2 nanoparticles in polyimide and low roughness was obtained after curing at 200 °C, resulting in a low leakage current density of the nano-composite film, when less than 2 vol % TiO2 nanoparticles were well dispersed in polyimide slurry. The dielectric constant of the organic-inorganic nanocomposite increases with increasing TiO2 content in polyimide, being situated in the range between 4 and 5.

  4. Solution processed self-assembled monolayer gate dielectrics for low-voltage organic transistors. : Section Title: Electric Phenomena

    NARCIS (Netherlands)

    Ball, James; Wobkenberg, Paul H.; Colleaux, Florian; Kooistra, Floris B.; Hummelen, Jan C.; Bradley, Donal D. C.; Anthopoulos, Thomas D.

    2008-01-01

    Low-voltage org. transistors are sought for implementation in high vol. low-power portable electronics of the future. Here we assess the suitability of three phosphonic acid based self-assembling mols. for use as ultra-thin gate dielecs. in low-voltage soln. processable org. field-effect transistors

  5. Evaluation of nanocomposite gate insulators for flexible organic thin-film transistors.

    Science.gov (United States)

    Kim, Jin Soo; Cho, Sung Won; Kim, Ii; Hwang, Byeong Ung; Seol, Young Gug; Kim, Tae Woong; Lee, Nae-Eung

    2014-11-01

    To develop physically flexible electronics, high performance and mechanical stability of component materials and devices are required. For a flexible display, a backplane with flexible thin-film transistors (TFTs) must be developed. Gate insulating materials with excellent electrical and mechanical properties are highly important to the development of flexible TFTs. We investigated nanocomposite gate dielectrics composed of polyimide (PI) because of their superior thermal stability, as well as different inorganic HfO2, TiO2, and Al2O3 nanoparticles with high dielectric constants. Nanocomposite gate dielectrics of HfO2 nanoparticles and PI lowered leakage current density and increased the relative dielectric constant compared to PI solely because of a high degree of dispersion. Pentacene TFTs with HfO2 nanocomposite gate insulators also showed higher field-effect mobility (μ), smaller subthreshold swing, and an enhanced on/off current ratio (I(on/off)) compared to those of the PI gate dielectric. In addition, mechanical cyclic bending tests involving bending cycles of 2 x 10(5) time sat a bending radius of 5 mm showed improvement in electrical stability of nanocomposite gate insulators with a change in leakage current density of nanocomposite gate insulators below 30%.

  6. Proton radiation hardness of single-nanowire transistors using robust organic gate nanodielectrics

    Science.gov (United States)

    Ju, Sanghyun; Lee, Kangho; Janes, David B.; Dwivedi, Ramesh C.; Baffour-Awuah, Habibah; Wilkins, R.; Yoon, Myung-Han; Facchetti, Antonio; Mark, Tobin J.

    2006-08-01

    In this contribution, the radiation tolerance of single ZnO nanowire field-effect transistors (NW-FETs) fabricated with a self-assembled superlattice (SAS) gate insulator is investigated and compared with that of ZnO NW-FETs fabricated with a 60nm SiO2 gate insulator. A total-radiation dose study was performed using 10MeV protons at doses of 5.71 and 285krad(Si ). The threshold voltage (Vth) of the SAS-based ZnO NW-FETs is not shifted significantly following irradiation at these doses. In contrast, Vth parameters of the SiO2-based ZnO NW-FETs display average shifts of ˜-4.0 and ˜-10.9V for 5.71 and 285krad(Si ) H+ irradiation, respectively. In addition, little change is observed in the subthreshold characteristics (off current, subthreshold slope) of the SAS-based ZnO NW-FETs following H+ irradiation. These results strongly argue that the bulk oxide trap density and interface trap density formed within the SAS and/or at the SAS-ZnO NW interface during H+ irradiation are significantly lower than those for the corresponding SiO2 gate dielectrics. The radiation-robust SAS-based ZnO NW-FETs are thus promising candidates for future space-based applications in electronics and flexible displays.

  7. Comparison of conductor and dielectric inks in printed organic complementary transistors

    Science.gov (United States)

    Ng, Tse Nga; Mei, Ping; Whiting, Gregory L.; Schwartz, David E.; Abraham, Biby; Wu, Yiliang; Veres, Janos

    2014-10-01

    Two types of printable conductor and a bilayer gate dielectric are evaluated for use in all-additive, inkjetprinted complementary OTFTs. The Ag nanoparticle ink based on nonpolar alkyl amine surfactant or stabilizer enables good charge injection into p-channel devices, but this ink also leaves residual stabilizer that modifies the transistor backchannel and shifts the turn-on voltage to negative values. The Ag ink based on polar solvent requires dopant modification to improve charge injection to p-channel devices, but this ink allows the OTFT turn-on voltage to be close to 0 V. The reverse trend is observed for n-channel OTFTs. For gate insulator, a bilayer dielectric is demonstrated that combines the advantages of two types of insulator materials, in which a fluoropolymer reduces dipolar disorder at the semiconductor-dielectric interface, while a high-k PVDF terpolymer dielectric facilitates high gate capacitance. The dielectric is incorporated into an inverter and a three-stage ring oscillator, and the resulting circuits were demonstrated to operate at a supply voltage as low as 2 V, with bias stress levels comparable to circuits with other types of dielectrics.

  8. Effect of UV/ozone treatment on polystyrene dielectric and its application on organic field-effect transistors

    Science.gov (United States)

    2014-01-01

    The influence of UV/ozone treatment on the property of polystyrene (PS) dielectric surface was investigated, and pentacene organic field-effect transistors (OFETs) based on the treated dielectric was fabricated. The dielectric and pentacene active layers were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results showed that, at short UVO exposure time (60 s), new chemical groups, including alcohol/ether, carbonyl, and carboxyl/ester groups, were formed. By adjusting the UVO exposure time to 5 s, the hole mobility of the OFETs increased to 0.52 cm2/Vs, and the threshold voltage was positively shifted to -12 V. While the time of UVO treatment exceeded 30 s, the mobility started to shrink, and the off-current was enlarged. These results indicate that, as a simple surface treatment method, UVO treatment could quantitatively modulate the property of PS dielectric surface by controlling the exposure time, and thus, pioneered a new way to modulate the characteristics of organic electronic devices. PMID:25258603

  9. Vertical Phase Separation in Small Molecule:Polymer Blend Organic Thin Film Transistors Can Be Dynamically Controlled

    KAUST Repository

    Zhao, Kui

    2016-02-03

    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Blending of small-molecule organic semiconductors (OSCs) with amorphous polymers is known to yield high performance organic thin film transistors (OTFTs). Vertical stratification of the OSC and polymer binder into well-defined layers is crucial in such systems and their vertical order determines whether the coating is compatible with a top and/or a bottom gate OTFT configuration. Here, we investigate the formation of blends prepared via spin-coating in conditions which yield bilayer and trilayer stratifications. We use a combination of in situ experimental and computational tools to study the competing effects of formulation thermodynamics and process kinetics in mediating the final vertical stratification. It is shown that trilayer stratification (OSC/polymer/OSC) is the thermodynamically favored configuration and that formation of the buried OSC layer can be kinetically inhibited in certain conditions of spin-coating, resulting in a bilayer stack instead. The analysis reveals here that preferential loss of the OSC, combined with early aggregation of the polymer phase due to rapid drying, inhibit the formation of the buried OSC layer. The fluid dynamics and drying kinetics are then moderated during spin-coating to promote trilayer stratification with a high quality buried OSC layer which yields unusually high mobility >2 cm2 V-1 s-1 in the bottom-gate top-contact configuration.

  10. Oxide Semiconductor-Based Flexible Organic/Inorganic Hybrid Thin-Film Transistors Fabricated on Polydimethylsiloxane Elastomer.

    Science.gov (United States)

    Jung, Soon-Won; Choi, Jeong-Seon; Park, Jung Ho; Koo, Jae Bon; Park, Chan Woo; Na, Bock Soon; Oh, Ji-Young; Lim, Sang Chul; Lee, Sang Seok; Chu, Hye Yong

    2016-03-01

    We demonstrate flexible organic/inorganic hybrid thin-film transistors (TFTs) on a polydimethysilox- ane (PDMS) elastomer substrate. The active channel and gate insulator of the hybrid TFT are composed of In-Ga-Zn-O (IGZO) and blends of poly(vinylidene fluoride-trifluoroethylene) [P(VDF- TrFE)] with poly(methyl methacrylate) (PMMA), respectively. It has been confirmed that the fabri- cated TFT display excellent characteristics: the recorded field-effect mobility, sub-threshold voltage swing, and I(on)/I(off) ratio were approximately 0.35 cm2 V(-1) s(-1), 1.5 V/decade, and 10(4), respectively. These characteristics did not experience any degradation at a bending radius of 15 mm. These results correspond to the first demonstration of a hybrid-type TFT using an organic gate insulator/oxide semiconducting active channel structure fabricated on PDMS elastomer, and demonstrate the feasibility of a promising device in a flexible electronic system. PMID:27455702

  11. Synthesis and Photophysical Studies of Thiadiazole[3,4-c]pyridine Copolymer Based Organic Field-Effect Transistors.

    Science.gov (United States)

    Bathula, Chinna; Lee, Sang Kyu; Kalode, Pranav; Badgujar, Sachin; Belavagi, Ningaraddi S; Khazi, Imtiyaz Ahmed M; Kang, Youngjong

    2016-05-01

    A novel thiadiazolo[3,4-c]pyridine] based donor-acceptor (D-A) copolymer, poly[4,8-bis(triisopropylsilylethynyl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-[4,7-bis(4-(2-ethylhexyl)thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine] (PTBDTPT), containing triisopropylsilylethynyl(TIPS)benzo[1,2-b:4,5-b']dithiophene as a donor is synthesized by Stille polymerization reaction. All the important photo physical prerequisites for organic field-effect transistor (OFET) application such as strong and broad optical absorption, thermal stability, and compatible HOMO-LUMO levels can be accomplished and combined on one macromolecule. Optical band gap of the polymer was found to be 1.61 eV as calculated from its film onset absorption edge. The hole mobility of bottom gate OFET using the synthesized polymer as an active channel is found to be 1.92 X 10(-2) cm V(-1) s(-1) with the On/Off ratio of 25. The photophysical study suggests that PTBDTPT is promising candidate for future large area organic electronic applications.

  12. 3.4-Inch Quarter High Definition Flexible Active Matrix Organic Light Emitting Display with Oxide Thin Film Transistor

    Science.gov (United States)

    Hatano, Kaoru; Chida, Akihiro; Okano, Tatsuya; Sugisawa, Nozomu; Inoue, Tatsunori; Seo, Satoshi; Suzuki, Kunihiko; Oikawa, Yoshiaki; Miyake, Hiroyuki; Koyama, Jun; Yamazaki, Shunpei; Eguchi, Shingo; Katayama, Masahiro; Sakakura, Masayuki

    2011-03-01

    In this paper, we report a 3.4-in. flexible active matrix organic light emitting display (AMOLED) display with remarkably high definition (quarter high definition: QHD) in which oxide thin film transistors (TFTs) are used. We have developed a transfer technology in which a TFT array formed on a glass substrate is separated from the substrate by physical force and then attached to a flexible plastic substrate. Unlike a normal process in which a TFT array is directly fabricated on a thin plastic substrate, our transfer technology permits a high integration of high performance TFTs, such as low-temperature polycrystalline silicon TFTs (LTPS TFTs) and oxide TFTs, on a plastic substrate, because a flat, rigid, and thermally-stable glass substrate can be used in the TFT fabrication process in our transfer technology. As a result, this technology realized an oxide TFT array for an AMOLED on a plastic substrate. Furthermore, in order to achieve a high-definition AMOLED, color filters were incorporated in the TFT array and a white organic light-emitting diode (OLED) was combined. One of the features of this device is that the whole body of the device can be bent freely because a source driver and a gate driver can be integrated on the substrate due to the high mobility of an oxide TFT. This feature means “true” flexibility.

  13. Effect of UV/ozone treatment on polystyrene dielectric and its application on organic field-effect transistors

    Science.gov (United States)

    Huang, Wei; Fan, Huidong; Zhuang, Xinming; Yu, Junsheng

    2014-09-01

    The influence of UV/ozone treatment on the property of polystyrene (PS) dielectric surface was investigated, and pentacene organic field-effect transistors (OFETs) based on the treated dielectric was fabricated. The dielectric and pentacene active layers were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results showed that, at short UVO exposure time (60 s), new chemical groups, including alcohol/ether, carbonyl, and carboxyl/ester groups, were formed. By adjusting the UVO exposure time to 5 s, the hole mobility of the OFETs increased to 0.52 cm2/Vs, and the threshold voltage was positively shifted to -12 V. While the time of UVO treatment exceeded 30 s, the mobility started to shrink, and the off-current was enlarged. These results indicate that, as a simple surface treatment method, UVO treatment could quantitatively modulate the property of PS dielectric surface by controlling the exposure time, and thus, pioneered a new way to modulate the characteristics of organic electronic devices.

  14. Oxide Semiconductor-Based Flexible Organic/Inorganic Hybrid Thin-Film Transistors Fabricated on Polydimethylsiloxane Elastomer.

    Science.gov (United States)

    Jung, Soon-Won; Choi, Jeong-Seon; Park, Jung Ho; Koo, Jae Bon; Park, Chan Woo; Na, Bock Soon; Oh, Ji-Young; Lim, Sang Chul; Lee, Sang Seok; Chu, Hye Yong

    2016-03-01

    We demonstrate flexible organic/inorganic hybrid thin-film transistors (TFTs) on a polydimethysilox- ane (PDMS) elastomer substrate. The active channel and gate insulator of the hybrid TFT are composed of In-Ga-Zn-O (IGZO) and blends of poly(vinylidene fluoride-trifluoroethylene) [P(VDF- TrFE)] with poly(methyl methacrylate) (PMMA), respectively. It has been confirmed that the fabri- cated TFT display excellent characteristics: the recorded field-effect mobility, sub-threshold voltage swing, and I(on)/I(off) ratio were approximately 0.35 cm2 V(-1) s(-1), 1.5 V/decade, and 10(4), respectively. These characteristics did not experience any degradation at a bending radius of 15 mm. These results correspond to the first demonstration of a hybrid-type TFT using an organic gate insulator/oxide semiconducting active channel structure fabricated on PDMS elastomer, and demonstrate the feasibility of a promising device in a flexible electronic system.

  15. Gravitational instability of filamentary molecular clouds, including ambipolar diffusion

    CERN Document Server

    Hosseinirad, Mohammad; Abbassi, Shahram; Roshan, Mahmood

    2016-01-01

    The gravitational instability of a filamentary molecular cloud in non-ideal magnetohydrodynamics is investigated. The filament is assumed to be in hydrostatic equilibrium. We add the effect of ambipolar diffusion to the filament which is threaded by an initial uniform axial magnetic field along its axis. We write down the fluid equations in cylindrical coordinates and perform linear perturbation analysis. We integrate the resultant differential equations and then derive the numerical dispersion relation. We find that, a more efficient ambipolar diffusion leads to an enhancement of the growth of the most unstable mode, and to increase of the fragmentation scale of the filament.

  16. Improved Performance of Pentacene Organic Field-Effect Transistors by Inserting a V2O5 Metal Oxide Layer

    Institute of Scientific and Technical Information of China (English)

    赵赓; 程晓曼; 田海军; 杜博群; 梁晓宇

    2011-01-01

    We fabricate pentacene-based organic field effect transistors(OFETs),inserting a transition metal oxide(V2 O5)layer between the pentacene and Al source-drain(S/D)electrodes.The performance of the devices with V2O5/AlS/D electrodes is considerably improved compared to the pentacene-based OFET with only Al S/D electrodes.After the 10-nm V2O5 layer modification,the effective field-effect mobility of the devices increases from 2.7 ×10-3 cm2 /V.s to 8.93 × 10-1 cm2 /V.s.Owing to the change of the injection property,the effective threshold voltage (Vth)is changed from-7.5 V to-5 V and the on/off ratio shifts from 102 to 104.Moreover,the dispersion of sub-threshold current in the devices disappears.These performance improvements are ascribed to the low carrier injection barrier and the reduction of contact resistance.It is indicated that V2O5 layer modification is an effective approach to improve pentacene-based OFET performance.%We fabricate pentacene-based organic field effect transistors (OFETs), inserting a transition metal oxide (V2O5) layer between the pentacene and Al source-drain (S/D) electrodes. The performance of the devices with V2 O5/AI S/D electrodes is considerably improved compared to the pentacene-based OFET with only Al S/D electrodes. After the 10-nm V2O5 layer modification, the effective field-effect mobility of the devices increases from 2.7 x 10~3 cm2/V-s to 8.93x10-1 cm2/V-s. Owing to the change of the injection property, the effective threshold voltage (Vth) is changed from -7.5 V to -5 V and the on/off ratio shifts from l02 to 104. Moreover, the dispersion of sub-threshold current in the devices disappears. These performance improvements are ascribed to the low carrier injection barrier and the reduction of contact resistance. It is indicated that V2O5 layer modification is an effective approach to improve pentacene-based OFET performance.

  17. Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells.

    Science.gov (United States)

    Chen, Weichao; Xiao, Manjun; Han, Liangliang; Zhang, Jidong; Jiang, Huanxiang; Gu, Chuantao; Shen, Wenfei; Yang, Renqiang

    2016-08-01

    Unsubstituted benzo[1,2-b:4,5-b']dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (-5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm(2) V(-1) s(-1). Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC71BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm(-2)) and high fill factor (0.751) without any process additives or thermal annealing. PMID:27403850

  18. Improving the Performance of Organic Thin-Film Transistors by Ion Doping of Ethylene-Glycol-Based Self-Assembled Monolayer Hybrid Dielectrics.

    Science.gov (United States)

    Dietrich, Hanno; Scheiner, Simon; Portilla, Luis; Zahn, Dirk; Halik, Marcus

    2015-12-22

    Tuning the electrostatics of ethylene-glycol-based self-assembled monolayers (SAMs) by doping with ions is shown. Molecular dynamics simulations unravel binding mechanisms and predict dipole strengths of the doped layers. Additionally, by applying such layers as dielectrics in organic thin-film transistors, the incorporated ions are proven to enhance device performance by lowering the threshold voltage and increasing conductivity. PMID:26524344

  19. Liquid Crystal-on-Organic Field-Effect Transistor Sensory Devices for Perceptive Sensing of Ultralow Intensity Gas Flow Touch

    Science.gov (United States)

    Seo, Jooyeok; Park, Soohyeong; Nam, Sungho; Kim, Hwajeong; Kim, Youngkyoo

    2013-08-01

    We demonstrate liquid crystal-on-organic field-effect transistor (LC-on-OFET) sensory devices that can perceptively sense ultralow level gas flows. The LC-on-OFET devices were fabricated by mounting LC molecules (4-cyano-4'-pentylbiphenyl - 5CB) on the polymer channel layer of OFET. Results showed that the presence of LC molecules on the channel layer resulted in enhanced drain currents due to a strong dipole effect of LC molecules. Upon applying low intensity nitrogen gas flows, the drain current was sensitively increased depending on the intensity and time of nitrogen flows. The present LC-on-OFET devices could detect extremely low level nitrogen flows (0.7 sccm-11 μl/s), which could not be felt by human skins, thanks to a synergy effect between collective behavior of LC molecules and charge-sensitive channel layer of OFET. The similar sensation was also achieved using the LC-on-OFET devices with a polymer film skin, suggesting viable practical applications of the present LC-on-OFET sensory devices.

  20. Amorphous silicon thin film transistor active-matrix organic light-emitting diode displays fabricated on flexible substrates

    Science.gov (United States)

    Nichols, Jonathan A.

    Organic light-emitting diode (OLED) displays are of immense interest because they have several advantages over liquid crystal displays, the current dominant flat panel display technology. OLED displays are emissive and therefore are brighter, have a larger viewing angle, and do not require backlights and filters, allowing thinner, lighter, and more power efficient displays. The goal of this work was to advance the state-of-the-art in active-matrix OLED display technology. First, hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) active-matrix OLED pixels and arrays were designed and fabricated on glass substrates. The devices operated at low voltages and demonstrated that lower performance TFTs could be utilized in active-matrix OLED displays, possibly allowing lower cost processing and the use of polymeric substrates. Attempts at designing more control into the display at the pixel level were also made. Bistable (one bit gray scale) active-matrix OLED pixels and arrays were designed and fabricated. Such pixels could be used in novel applications and eventually help reduce the bandwidth requirements in high-resolution and large-area displays. Finally, a-Si:H TFT active-matrix OLED pixels and arrays were fabricated on a polymeric substrate. Displays fabricated on a polymeric substrates would be lightweight; flexible, more rugged, and potentially less expensive to fabricate. Many of the difficulties associated with fabricating active-matrix backplanes on flexible substrates were studied and addressed.

  1. Unencapsulated Air-stable Organic Field Effect Transistor by All Solution Processes for Low Power Vapor Sensing

    Science.gov (United States)

    Feng, Linrun; Tang, Wei; Zhao, Jiaqing; Yang, Ruozhang; Hu, Wei; Li, Qiaofeng; Wang, Ruolin; Guo, Xiaojun

    2016-02-01

    With its excellent mechanical flexibility, low-cost and low-temperature processing, the solution processed organic field-effect transistor (OFET) is a promising platform technology for developing ubiquitous sensor applications in digital health, environment monitoring and Internet of Things. However, a contradiction between achieving low voltage operation and having stable performance severely hinder the technology to become commercially viable. This work shows that, by reducing the sub-gap density of states (DOS) at the channel for low operation voltage and using a proper low-k non-polar polymer dielectric layer, such an issue can be addressed. Stable electrical properties after either being placed for weeks or continuously prolonged bias stressing for hours in ambient air are achieved for all solution processed unencapsulated OFETs with the channel being exposed to the ambient air for analyte detection. The fabricated device presents a steep subthreshold swing less than 100 mV/decade, and an ON/OFF ratio of 106 at a voltage swing of 3 V. The low voltage and stable operation allows the sensor made of the OFET to be incorporated into a battery-powered electronic system for continuously reliable sensing of ammonia vapor in ambient air with very small power consumption of about 50 nW.

  2. Polymer Nanodot-Hybridized Alkyl Silicon Oxide Nanostructures for Organic Memory Transistors with Outstanding High-Temperature Operation Stability

    Science.gov (United States)

    Lee, Chulyeon; Seo, Jooyeok; Kim, Jeongnam; Jeong, Jaehoon; Han, Hyemi; Kim, Hwajeong; Kim, Youngkyoo

    2016-01-01

    Organic memory devices (OMDs) are becoming more important as a core component in flexible electronics era because of their huge potentials for ultrathin, lightweight and flexible plastic memory modules. In particular, transistor-type OMDs (TOMDs) have been gradually spotlighted due to their structural advantages possessing both memory and driving functions in single devices. Although a variety of TOMDs have been developed by introducing various materials, less attention has been paid to the stable operation at high temperatures. Here we demonstrate that the polymer nanodot-embedded alkyl silicon oxide (ASiO) hybrid materials, which are prepared by sol-gel and thermal cross-linking reactions between poly(4-vinylphenol) (PVP) and vinyltriethoxysilane, can deliver low-voltage (1~5 V) TOMDs with outstanding operation stability (>4700 cycles) at high temperatures (150 °C). The efficient low-voltage memory function is enabled by the embedded PVP nanodots with particular lattice nanostructures, while the high thermal stability is achieved by the cross-linked ASiO network structures. PMID:27703187

  3. High performance ZnO nanowire field effect transistors with organic gate nanodielectrics: effects of metal contacts and ozone treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Sanghyun [School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 (United States); Lee, Kangho [School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 (United States); Yoon, Myung-Han [Department of Chemistry and Materials Research Center, and Institute for Nanoelectronics and Computing, Northwestern University, Evanston, IL 60208-3113 (United States); Facchetti, Antonio [Department of Chemistry and Materials Research Center, and Institute for Nanoelectronics and Computing, Northwestern University, Evanston, IL 60208-3113 (United States); Marks, Tobin J [Department of Chemistry and Materials Research Center, and Institute for Nanoelectronics and Computing, Northwestern University, Evanston, IL 60208-3113 (United States); Janes, David B [School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 (United States)

    2007-04-18

    High performance ZnO nanowire field effect transistors (NW-FETs) were fabricated using a nanoscopic self-assembled organic gate insulator and characterized in terms of conventional device performance metrics. To optimize device performance and understand the effects of interface properties, devices were fabricated with both Al and Au/Ti source/drain contacts, and device electrical properties were characterized following annealing and ozone treatment. Ozone-treated single ZnO NW-FETs with Al contacts exhibited an on-current (I{sub on}) of {approx}4 {mu}A at 0.9 V{sub gs} and 1.0 V{sub ds}, a threshold voltage (V{sub th}) of 0.2 V, a subthreshold slope (S) of {approx}130 mV/decade, an on-off current ratio (I{sub on}:I{sub off}) of {approx}10{sup 7}, and a field effect mobility ({mu}{sub eff}) of {approx}1175 cm{sup 2} V{sup -1} s{sup -1}. In addition, ozone-treated ZnO NW-FETs consistently retained the enhanced device performance metrics after SiO{sub 2} passivation. A 2D device simulation was performed to explain the enhanced device performance in terms of changes in interfacial trap and fixed charge densities.

  4. High performance ZnO nanowire field effect transistors with organic gate nanodielectrics: effects of metal contacts and ozone treatment

    Science.gov (United States)

    Ju, Sanghyun; Lee, Kangho; Yoon, Myung-Han; Facchetti, Antonio; Marks, Tobin J.; Janes, David B.

    2007-04-01

    High performance ZnO nanowire field effect transistors (NW-FETs) were fabricated using a nanoscopic self-assembled organic gate insulator and characterized in terms of conventional device performance metrics. To optimize device performance and understand the effects of interface properties, devices were fabricated with both Al and Au/Ti source/drain contacts, and device electrical properties were characterized following annealing and ozone treatment. Ozone-treated single ZnO NW-FETs with Al contacts exhibited an on-current (Ion) of ~4 µA at 0.9 Vgs and 1.0 Vds, a threshold voltage (Vth) of 0.2 V, a subthreshold slope (S) of ~130 mV/decade, an on-off current ratio (Ion:Ioff) of ~107, and a field effect mobility (μeff) of ~1175 cm2 V-1 s-1. In addition, ozone-treated ZnO NW-FETs consistently retained the enhanced device performance metrics after SiO2 passivation. A 2D device simulation was performed to explain the enhanced device performance in terms of changes in interfacial trap and fixed charge densities.

  5. Exposure to volatile organic compounds and kidney dysfunction in thin film transistor liquid crystal display (TFT-LCD) workers.

    Science.gov (United States)

    Chang, Ta-Yuan; Huang, Kuei-Hung; Liu, Chiu-Shong; Shie, Ruei-Hao; Chao, Keh-Ping; Hsu, Wen-Hsin; Bao, Bo-Ying

    2010-06-15

    Many volatile organic compounds (VOCs) are emitted during the manufacturing of thin film transistor liquid crystal displays (TFT-LCDs), exposure to some of which has been reported to be associated with kidney dysfunction, but whether such an effect exists in TFT-LCD industry workers is unknown. This cross-sectional study aimed to investigate the association between exposure to VOCs and kidney dysfunction among TFT-LCD workers. The results showed that ethanol (1811.0+/-1740.4 ppb), acetone (669.0+/-561.0 ppb), isopropyl alcohol (187.0+/-205.3 ppb) and propylene glycol monomethyl ether acetate (PGMEA) (102.9+/-102.0 ppb) were the four dominant VOCs present in the workplace. The 63 array workers studied had a risk of kidney dysfunction 3.21-fold and 3.84-fold that of 61 cell workers and 18 module workers, respectively. Workers cumulatively exposed to a total level of isopropyl alcohol, PGMEA and propylene glycol monomethyl ether> or =324 ppb-year had a significantly higher risk of kidney dysfunction (adjusted OR=3.41, 95% CI=1.14-10.17) compared with those exposed to LCD industry, and cumulative exposure to specific VOCs might be associated with kidney dysfunction.

  6. Air-stable solution-processed n-channel organic thin film transistors with polymer-enhanced morphology

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Li, Dawen, E-mail: dawenl@eng.ua.edu [Department of Electrical and Computer Engineering, Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Chen, Jihua [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-05-04

    N,N′-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN{sub 2}) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN{sub 2} film is much lower than the value of PDIF-CN{sub 2} single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PαMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN{sub 2} thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PαMS or PMMA polymers, the morphology of the PDIF-CN{sub 2} polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm{sup 2}/V s has been achieved from OTFTs based on the PDIF-CN{sub 2} film with the pre-deposition of PαMS polymer.

  7. The mobility improvement of organic thin film transistors by introducing ZnO-nanrods as an zctive layer

    Institute of Scientific and Technical Information of China (English)

    XIE Tao; XIE GuangZhong; DU HongFei; YE ZongBiao; SU YuanJie; CHEN YuYan

    2016-01-01

    Organic thin film transistors (OTFTs) based on poly(3-hexylthiophene) (P3HT)/Zinc oxide (ZnO) nanorods composite films as the active layers were prepared by spray-coating process.The OTFI's with P3HT/ZnO-nanorods composite films owned higher carriers mobility than the OTFT based on pure P3HT.It can be found that the mobility of OTFTs increased by 135% due to ZnO-nanorods doping.This was attributed to the improvement of the P3HT crystallinity and the optimization of polymer chains orientation.Meanwhile,because of the distinction of work function between P3HT and ZnO,the majority carriers would accumulate on either side of the P3HT-ZnO interface which benefited carrier transfer.The influence on the mobility of composite film was studied.In addition,the threshold voltage of devices changed positively with the increase of ZnO-nanorods due to the decrease of electrostatic potential for P3HT/ZnO-nanorods composite films.The effect could be explained by the energy level theory of semiconductor.

  8. Cyanoethyl cellulose-based nanocomposite dielectric for low-voltage, solution-processed organic field-effect transistors (OFETs)

    Science.gov (United States)

    Faraji, Sheida; Danesh, Ehsan; Tate, Daniel J.; Turner, Michael L.; Majewski, Leszek A.

    2016-05-01

    Low voltage organic field-effect transistors (OFETs) using solution-processed cyanoethyl cellulose (CEC) and CEC-based nanocomposites as the gate dielectric are demonstrated. Barium strontium titanate (BST) nanoparticles are homogeneously dispersed in CEC to form the high-k (18.0  ±  0.2 at 1 kHz) nanocomposite insulator layer. The optimised p-channel DPPTTT OFETs with BST-CEC nanocomposite as the gate dielectric operate with minimal hysteresis, display field-effect mobilities in excess of 1 cm2 V‑1 s‑1 at 3 V, possess low subthreshold swings (132  ±  8 mV dec‑1), and have on/off ratios greater than 103. Addition of a 40–50 nm layer of cross-linked poly(vinyl phenol) (PVP) on the surface of the nanocomposite layer significantly decreases the gate leakage current (<10‑7 A cm‑2 at  ±3 V) and the threshold voltage (<  ‑0.7 V) enabling operation of the OFETs at 1.5 V. The presented bilayer BST-CEC/PVP dielectrics are a promising alternative for the fabrication of low voltage, solution-processed OFETs that are suitable for use in low power, portable electronics.

  9. Printable organic thin film transistors for glucose detection incorporating inkjet-printing of the enzyme recognition element

    Energy Technology Data Exchange (ETDEWEB)

    Elkington, D., E-mail: Daniel.Elkington@newcastle.edu.au; Wasson, M.; Belcher, W.; Dastoor, P. C.; Zhou, X. [Centre for Organic Electronics, The University of Newcastle, Callaghan 2308 (Australia)

    2015-06-29

    The effect of device architecture upon the response of printable enzymatic glucose sensors based on poly(3-hexythiophene) (P3HT) organic thin film transistors is presented. The change in drain current is used as the basis for glucose detection and we show that significant improvements in drain current response time can be achieved by modifying the design of the sensor structure. In particular, we show that eliminating the dielectric layer and reducing the thickness of the active layer reduce the device response time considerably. The results are in good agreement with a diffusion based model of device operation, where an initial rapid dedoping process is followed by a slower doping of the P3HT layer from protons that are enzymatically generated by glucose oxidase (GOX) at the Nafion gate electrode. The fitted diffusion data are consistent with a P3HT doping region that is close to the source-drain electrodes rather than located at the P3HT:[Nafion:GOX] interface. Finally, we demonstrate that further improvements in sensor structure and morphology can be achieved by inkjet-printing the GOX layer, offering a pathway to low-cost printed biosensors for the detection of glucose in saliva.

  10. Field effect transistors based on polycyclic aromatic hydrocarbons for the detection and classification of volatile organic compounds.

    Science.gov (United States)

    Bayn, Alona; Feng, Xinliang; Müllen, Klaus; Haick, Hossam

    2013-04-24

    We show that polycyclic aromatic hydrocarbon (PAH) based field effect transistor (FET) arrays can serve as excellent chemical sensors for the detection of volatile organic compounds (VOCs) under confounding humidity conditions. Using these sensors, w/o complementary pattern recognition methods, we study the ability of PAH-FET(s) to: (i) discriminate between aromatic and non-aromatic VOCs; (ii) distinguish polar and non-polar non-aromatic compounds; and to (iii) identify specific VOCs within the subgroups (i.e., aromatic compounds, polar non-aromatic compounds, non-polar non-aromatic compounds). We further study the effect of water vapor on the sensor array's discriminative ability and derive patterns that are stable when exposed to different constant values of background humidity. Patterns based on different independent electronic features from an array of PAH-FETs may bring us one step closer to creating a unique fingerprint for individual VOCs in real-world applications in atmospheres with varying levels of humidity.

  11. Organic Ferroelectric Field-Effect Transistor Memory Using Flat Poly(vinylidene fluoride-tetrafluoroethylene) and Pentacene Thin Films

    Science.gov (United States)

    Kanashima, Takeshi; Yabe, Kazuki; Okuyama, Masanori

    2012-02-01

    Organic ferroelectric field-effect transistor (FET) memories have been fabricated using pentacene as the semiconductor and a flat poly(vinylidene fluoride-tetrafluoroethylene) [P(VDF-TeFE)] thin film as the ferroelectric gate. The P(VDF-TeFE) film is prepared by spin coating, and it was cooled slowly with a flattening process after annealing. The polarization-electric field (P-E) hysteresis of the P(VDF-TeFE) thin film prepared by slow cooling is larger than that in the case of quick cooling. Moreover, the flattening process does not have a negative effect on ferroelectric properties. The obtained remanent polarization (Pr) of 5.2 µC/cm2 is sufficient for controlling the pentacene surface potential. Good memory characteristics are obtained in the P(VDF-TeFE) gate FET with pentacene deposited on the flat P(VDF-TeFE). The maximum drain current is about twice larger than that deposited on the rough P(VDF-TeFE) prepared by quick cooling, and the memory retention is over 1 week.

  12. Printable organic thin film transistors for glucose detection incorporating inkjet-printing of the enzyme recognition element

    Science.gov (United States)

    Elkington, D.; Wasson, M.; Belcher, W.; Dastoor, P. C.; Zhou, X.

    2015-06-01

    The effect of device architecture upon the response of printable enzymatic glucose sensors based on poly(3-hexythiophene) (P3HT) organic thin film transistors is presented. The change in drain current is used as the basis for glucose detection and we show that significant improvements in drain current response time can be achieved by modifying the design of the sensor structure. In particular, we show that eliminating the dielectric layer and reducing the thickness of the active layer reduce the device response time considerably. The results are in good agreement with a diffusion based model of device operation, where an initial rapid dedoping process is followed by a slower doping of the P3HT layer from protons that are enzymatically generated by glucose oxidase (GOX) at the Nafion gate electrode. The fitted diffusion data are consistent with a P3HT doping region that is close to the source-drain electrodes rather than located at the P3HT:[Nafion:GOX] interface. Finally, we demonstrate that further improvements in sensor structure and morphology can be achieved by inkjet-printing the GOX layer, offering a pathway to low-cost printed biosensors for the detection of glucose in saliva.

  13. Low-temperature processable inherently photosensitive polyimide as a gate insulator for organic thin-film transistors

    Science.gov (United States)

    Pyo, Seungmoon; Son, Hyunsam; Choi, Kil-Yeong; Yi, Mi Hye; Hong, Sung Kwon

    2005-03-01

    We have fabricated organic thin-film transistors (OTFTs) on polyethersulfone substrate using low-temperature processable, inherently photosensitive polyimide as the gate insulator and pentacene as the active material. The polyimide was prepared through two-step reaction. The polyimide precursor, poly(amic acid), was prepared from a dianhydride and aromatic diamine through a polycondensation reaction, and subsequently converted to its corresponding polyimide by a chemical imidization. Photolithographic properties of the polyimide are investigated. The pattern resolution of the cured polyimide was about 50μm. The pentacene OTFTs with the patterned polyimide were obtained with a carrier mobility of 0.1cm2/Vs and ION/IOFF of 5×105. The OTFT characteristics are discussed in more detail with respect to the electrical properties of the photosensitive polyimide thin film. This low-temperature photopatternable polyimide paves the way for the easy and low-cost fabrication of OTFT arrays without expensive and complicated photolithography and dry etching processes.

  14. Field-Effect Modulation of Ambipolar Doping and Domain Wall Band Alignment in P-type Vanadium Dioxide Nanowires

    Science.gov (United States)

    Hou, Yasen; Peng, Xingyue; Yang, Yiming; Yu, Dong

    The sub-picosecond metal-insulator phase transition in vanadium dioxide (VO2) has attracted extensive attention with potential applications in ultrafast Mott transistors. However, the development of VO2-based transistors lags behind, owing to the lack of an efficient and hysteresis-free electrostatic doping control. Here we report the first synthesis of p-type single crystalline VO2nanowires via catalyst-free chemical vapor deposition. The p-type doping was unambiguously confirmed by both solid and electrochemical gating methods, and further evidenced by the scanning photocurrent microscopic measurements. Interestingly, we observed that the photocurrent spot polarity at the metal-insulator domain walls was reversibly switched by electrochemical gating, which indicates a band bending flipping. Furthermore, we eliminated the common hysteresis in gate sweep and greatly shortened the transistor response time via a hybrid gating method, which combines the merits of liquid ionic and solid gating. The capability of efficient field effect modulation of ambipolar conduction and band alignment offers new opportunities on understanding the phase transition mechanism and enables novel electronic applications based on VO2.

  15. Polyimide Dielectric Layer on Filaments for Organic Field Effect Transistors: Choice of Solvent, Solution Composition and Dip-Coating Speed

    Directory of Open Access Journals (Sweden)

    Rambausek Lina

    2014-09-01

    Full Text Available In today’s research, smart textiles is an established topic in both electronics and the textile fields. The concept of producing microelectronics directly on a textile substrate is not a mere idea anymore and several research institutes are working on its realisation. Microelectronics like organic field effect transistor (OFET can be manufactured with a layered architecture. The production techniques used for this purpose can also be applied on textile substrates. Besides gate, active and contact layers, the isolating or dielectric layer is of high importance in the OFET architecture. Therefore, generating a high quality dielectric layer that is of low roughness and insulating at the same time is one of the fundamental requirements in building microelectronics on textile surfaces. To evaluate its potential, we have studied polyimide as a dielectric layer, dip-coated onto copper-coated polyester filaments. Accordingly, the copper-coated polyester filament was dip-coated from a polyimide solution with two different solvents, 1-methyl-2-pyrrolidone (NMP and dimethylformaldehyde. A variety of dip-coating speeds, solution concentrations and solvent-solute combinations have been tested. Their effect on the quality of the layer was analysed through microscopy, leak current measurements and atomic force microscopy (AFM. Polyimide dip-coating with polyimide resin dissolved in NMP at a concentration of 15w% in combination with a dip-coating speed of 50 mm/min led to the best results in electrical insulation and roughness. By optimising the dielectric layer’s properties, the way is paved for applying the subsequent semi-conductive layer. In further research, we will be working with the organic semiconductor material TIPS-Pentacene

  16. Dynamics of Threshold Voltage Shifts in Organic and Amorphous Silicon Field-Effect Transistors

    NARCIS (Netherlands)

    Mathijssen, S.G.J.; Cölle, M.; Gomes, H.; Smits, E.C.P.; Boer, B. de; McCulloch, I.; Bobbert, P.A.; Leeuw, D.M. de

    2006-01-01

    Progress in environmental stability and processability, and the increase of the field-effect mobility of organic semiconductors has triggered their use as the active element in microelectronic devices. The advantages of their application are the easy processing, for example, spin-coating and ink-jet

  17. High-performance organic broadband photomemory transistors exhibiting remarkable UV-NIR response.

    Science.gov (United States)

    Du, Lili; Luo, Xiao; Lv, Wenli; Zhao, Feiyu; Peng, Yingquan; Tang, Ying; Wang, Ying

    2016-05-14

    The electrical and optical properties of organic semiconductors have improved rapidly in recent years, rendering them highly promising for various optoelectronic applications owing to low-cost and lightweight potential in combination with spectral tunability and long photocarrier lifetimes. Organic photomemory has emerged as an innovative application to achieve optical data storage. However, practical operation requires universal device design with broader spectral response in terms of related materials, interfaces and architecture, a task that remains a significant challenge. Herein, we present a universal strategy to fabricate organic broadband photomemories featuring remarkable UV-NIR response, thereby providing optical switching ability with a controllable memory window. To the best of our knowledge, this study demonstrates an excellent performance with the broadest response spectra and the highest photomemory efficiency of up to 593%. We systematically study the charge trapping mechanism and photoinduced injection enhancement by combining an energy level model with theoretical calculations, characterizing conceivable photogenerated minority carrier trapping and accumulation kinetics. Thus, it is anticipated that the proposed approach will be a starting point for further research, resulting in high-performance organic photomemory ideal for digital commutation between optical and electric signals. PMID:27113427

  18. Graphene electrodes for n-type organic field-effect transistors

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Boggild, P.

    2010-01-01

    This work presents a convenient and contamination safe E-beam lithography process for microstructuring of graphene flakes. Exfoliated graphene flakes were deposited on oxidized silicon wafers and subsequently patterned by E-beam lithography, to be used as source and drain electrodes in an organic...

  19. 有机场效应晶体管的研究与应用进展%Progress in Organic Field-Effect Transistors and Its Applications

    Institute of Scientific and Technical Information of China (English)

    陈淑芬; 戴春雷; 牟鑫; 袁顺东; 翁洁娜; 凌启淡; 黄维

    2011-01-01

    有机场效应晶体管(Organic Field Effect Transistors,OFETs)是以有机半导体材料作为有源层的晶体管器件.和传统的无机半导体器件相比,由于其可应用于生产大面积柔性设备而被人们广泛的研究,在有机发光、有机光探测器、有机太阳能电池、压力传感器、有机存储设备、柔性平板显示、电子纸等众多领域具有潜在而广泛的应用前景.文中对OFET结构和工作原理做了简要介绍,之后重点讨论了最近几年来OFET中有机材料和绝缘体材料的发展状况,接着总结了OFET制备技术及其应用新领域,最后对OFET发展面临问题及应用前景做了归纳和展望.%Organic field-effect transistors (OFETs) are the transistors using organic semiconductive materi-als as the active layers. In comparison with conventional inorganic transistors, OFETs have attracted exten-sive attention due to their potential applications in large area and flexible opto-electronic devices, such as organic light emitting diodes (OLEDs) , organic photo detectors (OPDs) , organic solar cells, pressure sen-sors, organic memory elements,flexible flat panel displays,electronic papers,and so on. The device struc-ture and operating principle of OFET are briefly introduced in the beginning of the paper. The develop-ment of organic materials, fabrication technologies and potential applications of OFETs in the past few years are reviewed comprehensively. Finally,the development of OFETs in the future is prospected.

  20. Direct structural mapping of organic field-effect transistors reveals bottlenecks to carrier transport

    KAUST Repository

    Li, Ruipeng

    2012-08-10

    X-ray microbeam scattering is used to map the microstructure of the organic semiconductor along the channel length of solution-processed bottom-contact OFET devices. Contact-induced nucleation is known to influence the crystallization behavior within the channel. We find that microstructural inhomogeneities in the center of the channel act as a bottleneck to charge transport. This problem can be overcome by controlling crystallization of the preferable texture, thus favoring more efficient charge transport throughout the channel. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Interdependence of contact properties and field- and density-dependent mobility in organic field-effect transistors

    Science.gov (United States)

    Scheinert, Susanne; Paasch, Gernot

    2009-01-01

    The current characteristics of organic field-effect transistors (OFET) often show a disadvantageous nonlinearity at low drain voltages. It has been shown recently [J. Appl. Phys. 102, 054509 (2007)] that in top contact (TOC) OFETs this effect can be caused by trap recharging if the contacts are of Schottky type. For bottom contact (BOC) OFETs, in spite of controversial discussions, Schottky contacts as origin of the nonlinearity are often stated. At first, it is shown here by a mixed mode simulation that for large ideality factors a Schottky contact only at drain leads to such a nonlinearity. However, with the same Schottky contacts at drain and source the effect is covered by the high resistance of the contact at source. Next, the different influences of Schottky contacts on BOC OFETs and TOC OFETs with varying overlap of the source/drain contacts with the gate are clarified. Further, it is demonstrated with detailed two-dimensional simulations that the combination of the presence of Schottky contacts with a field dependence of the mobility can cause the nonlinearity. For the mobility we use the field dependent Pool/Frenkel model, and the models of Limketai et al.[Phys. Rev. B 75, 113203 (2007)] and Pasveer/Coehoorn et al.[Phys. Rev. Lett. 94, 206601 (2005)], which depend in addition on the carrier concentration. Their influence on the device performance has been clarified by the simulations. Simulated profiles of concentrations and fields lead to the understanding of the mechanism causing the nonlinearity. This mechanism is especially effective for the Pasveer/Coehoorn model. The field dependence of the mobility is a consequence of the energetic distribution of the hopping states and can hardly be avoided in solution based deposition of the active polymer layer. A strategy to prevent the nonlinearity is therefore an optimization of the contact-polymer interface such that the contacts become Ohmic.

  2. Microtexturing of the conductive PEDOT:PSS Polymer for superhydrophobic organic electrochemical transistors

    KAUST Repository

    Gentile, Francesco

    2014-01-22

    Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry and materials science to obtain an advanced device where, on account of the superhydrophobicity of the system, the solutions of interest can be manipulated and, on account of the conductive PEDOT:PSS polymer, the charged molecules dispersed inside can be quantitatively measured. This original substrate preparation allowed to perform electrochemical measurements on ionized species in solution with decreasing concentration down to 10 -7 molar. Moreover, it was demonstrated the ability of the device of realizing specific, combined time and space resolved analysis of the sample. Collectively, these results demonstrate how a tight, interweaving integration of different disciplines can provide realistic tools for the detection of pathologies. The scheme here introduced offers breakthrough capabilities that are expected to radically improve both the pace and the productivity of biomedical research, creating an access revolution. 2014 Francesco Gentile et al.

  3. Microtexturing of the Conductive PEDOT:PSS Polymer for Superhydrophobic Organic Electrochemical Transistors

    Directory of Open Access Journals (Sweden)

    Francesco Gentile

    2014-01-01

    Full Text Available Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry and materials science to obtain an advanced device where, on account of the superhydrophobicity of the system, the solutions of interest can be manipulated and, on account of the conductive PEDOT:PSS polymer, the charged molecules dispersed inside can be quantitatively measured. This original substrate preparation allowed to perform electrochemical measurements on ionized species in solution with decreasing concentration down to 10−7 molar. Moreover, it was demonstrated the ability of the device of realizing specific, combined time and space resolved analysis of the sample. Collectively, these results demonstrate how a tight, interweaving integration of different disciplines can provide realistic tools for the detection of pathologies. The scheme here introduced offers breakthrough capabilities that are expected to radically improve both the pace and the productivity of biomedical research, creating an access revolution.

  4. 2,6-Bis(benzo[b]thiophen-2-yl-3,7-dipentadecyltetrathienoacene (DBT-TTAR2 as an Alternative of Highly Soluble p-type Organic Semiconductor for Organic Thin Film Transistor (OTFT Application

    Directory of Open Access Journals (Sweden)

    Mery B. Supriadi

    2013-03-01

    Full Text Available A new compound of organic semiconductor based on tetrathienoacene (TTA derivatives, DBT-TTAR2 was synthesized and characterized. The corporation of dibenzo[b,d]thiophene (DBT group and alkyl substituent in both ends of TTA core have a significant effect on their π-π molecular conjugation length, energy gaps value and solubility properties. DBT-TTAR2 is fabricated as p-type organic semiconductor of organic thin film transistor (OTFT by solution process at Industrial Technology Research Institute, Taiwan. A good optical, electrochemical, and thermal properties of DBT-TTAR2 showed that its exhibits a better performance as highly soluble p-type organic semiconductor.

  5. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.

    2010-07-12

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C60, with bottom-contact mobilities of ?0.5 and ?1 cm2 V-1 s-1, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Threshold-Voltage-Shift Compensation and Suppression Method Using Hydrogenated Amorphous Silicon Thin-Film Transistors for Large Active Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Oh, Kyonghwan; Kwon, Oh-Kyong

    2012-03-01

    A threshold-voltage-shift compensation and suppression method for active matrix organic light-emitting diode (AMOLED) displays fabricated using a hydrogenated amorphous silicon thin-film transistor (TFT) backplane is proposed. The proposed method compensates for the threshold voltage variation of TFTs due to different threshold voltage shifts during emission time and extends the lifetime of the AMOLED panel. Measurement results show that the error range of emission current is from -1.1 to +1.7% when the threshold voltage of TFTs varies from 1.2 to 3.0 V.

  7. Poly(4-vinylphenol gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2016-03-01

    Full Text Available A Microwave-Induction Heating (MIH scheme is proposed for the poly(4-vinylphenol (PVP gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  8. INFLUENCE OF FILM STRUCTURE AND LIGHT ON CHARGE TRAPPING AND DISSIPATION DYNAMICS IN SPUN-CAST ORGANIC THIN-FILM TRANSISTORS MEASURED BY SCANNING KELVIN PROBE MICROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Teague, L.; Moth, M.; Anthony, J.

    2012-05-03

    Herein, time-dependent scanning Kelvin probe microscopy of solution processed organic thin film transistors (OTFTs) reveals a correlation between film microstructure and OTFT device performance with the location of trapped charge within the device channel. The accumulation of the observed trapped charge is concurrent with the decrease in I{sub SD} during operation (V{sub G}=-40 V, V{sub SD}= -10 V). We discuss the charge trapping and dissipation dynamics as they relate to the film structure and show that application of light quickly dissipates the observed trapped charge.

  9. Low-voltage Organic Thin Film Transistors (OTFTs) with Solution-processed High-k Dielectric cum Interface Engineering

    Science.gov (United States)

    Su, Yaorong

    Although impressive progress has been made in improving the performance of organic thin film transistors (OTFTs), the high operation voltage resulting from the low gate areal capacitance of traditional SiO 2 remains a severe limitation that hinders OTFTs' development in practical applications. In this regard, developing new materials with high- k characteristics at low cost is of great scientific and technological importance in the area of both academia and industry. In this thesis, we first describe a simple solution-based method to fabricate a high-k bilayer Al2Oy/TiOx (ATO) dielectric system at low temperature. Then the dielectric properties of the ATO are characterized and discussed in detail. Furthermore, by employing the high-k ATO as gate dielectric, low-voltage copper phthalocyanine (CuPc) based OTFTs are successfully developed. Interestingly, the obtained low-voltage CuPc TFT exhibits outstanding electrical performance, which is even higher than the device fabricated on traditional low-k SiO2. The above results seem to be contradictory to the reported results due to the fact that high-k usually shows adverse effect on the device performance. This abnormal phenomenon is then studied in detail. Characterization on the initial growth shows that the CuPc molecules assemble in a "rod-like" nano crystal with interconnected network on ATO, which probably promotes the charge carrier transport, whereas, they form isolated small islands with amorphous structure on SiO2. In addition, a better metal/organic contact is observed on ATO, which benefits the charge carrier injection. Our studies suggest that the low-temperature, solution-processed high-k ATO is a promising candidate for fabrication of high-performance, low-voltage OTFTs. Furthermore, it is well known that the properties of the dielectric/semiconductor and electrode/semiconductor interfaces are crucial in controlling the electrical properties of OTFTs. Hence, investigation the effects of interfaces

  10. A Soluble Dynamic Complex Strategy for the Solution-Processed Fabrication of Organic Thin-Film Transistors of a Boron-Containing Polycyclic Aromatic Hydrocarbon.

    Science.gov (United States)

    Matsuo, Kyohei; Saito, Shohei; Yamaguchi, Shigehiro

    2016-09-19

    The solution-processed fabrication of thin films of organic semiconductors enables the production of cost-effective, large-area organic electronic devices under mild conditions. The formation/dissociation of a dynamic B-N coordination bond can be used for the solution-processed fabrication of semiconducting films of polycyclic aromatic hydrocarbon (PAH) materials. The poor solubility of a boron-containing PAH in chloroform, toluene, and chlorobenzene was significantly improved by addition of minor amounts (1 wt % of solvent) of pyridine derivatives, as their coordination to the boron atom suppresses the inherent propensity of the PAHs to form π-stacks. Spin-coating solutions of the thus formed Lewis acid-base complexes resulted in the formation of amorphous thin films, which could be converted into polycrystalline films of the boron-containing PAH upon thermal annealing. Organic thin-film transistors prepared by this solution process displayed typical p-type characteristics. PMID:27576306

  11. Flip-flop logic circuit based on fully solution-processed organic thin film transistor devices with reduced variations in electrical performance

    Science.gov (United States)

    Takeda, Yasunori; Yoshimura, Yudai; Adib, Faiz Adi Ezarudin Bin; Kumaki, Daisuke; Fukuda, Kenjiro; Tokito, Shizuo

    2015-04-01

    Organic reset-set (RS) flip-flop logic circuits based on pseudo-CMOS inverters have been fabricated using full solution processing at a relatively low process temperatures of 150 °C or less. The work function for printed silver electrodes was increased from 4.7 to 5.4 eV through surface modification with a self-assembled monolayer (SAM) material. A bottom-gate, bottom-contact organic thin-film transistor (OTFT) device using a solution-processable small-molecular semiconductor material exhibited field-effect mobility of 0.40 cm2 V-1 s-1 in the saturation region and a threshold voltage (VTH) of -2.4 V in ambient air operation conditions. In order to reduce the variations in mobility and VTH, we designed a circuit with six transistors arranged in parallel, in order to average out their electrical characteristics. As a result, we have succeeded in reducing these variations without changing the absolute values of the mobility and VTH. The fabricated RS flip-flop circuits were functioned well and exhibited short delay times of 3.5 ms at a supply voltage of 20 V.

  12. Pixel Design of Organic Thin Film Transistor Array%有机薄膜晶体管阵列面向电子纸像素设计

    Institute of Scientific and Technical Information of China (English)

    汪梅林; 张其国; 郑永亮; 秦永亮; 郭晓东; 潭莉; 朱棋锋; 韩学斌; 申剑锋

    2012-01-01

    As a switch device of the pixel, the Organic Thin Film Transistor(OTFT) has good IDS-VGS curve. This paper describes the pixel circuit, model parameter for HSPICE simulation and the pixel layout. In order to verify the influence of storage capacitor and TFT structure on the pixel waveform, the pixel waveform was simulated by HSPICE. The OTFT process is studied in this paper. Result shows that OTFT structure is selected according to the storage capacitor for different products. The OTFT process is suitable for flexible display.%讨论了有机薄膜晶体管(Organic Thin Film Transistor,OTFT)作为开关器件来驱动电子纸的像素设计,特别是像素电路结构、HSPICE模拟用模型参数和像素平面结构.讨论了有机薄膜晶体管制造过程,并用HSPIC模拟分析了有机薄膜晶体管结构和存贮电容大小对像素波形的影响,结果表明TFT结构的选择依赖于存贮电容的大小.

  13. Tailoring the Dielectric Layer Structure for Enhanced Performance of Organic Field-Effect Transistors: The Use of a Sandwiched Polar Dielectric Layer

    Directory of Open Access Journals (Sweden)

    Shijiao Han

    2016-07-01

    Full Text Available To investigate the origins of hydroxyl groups in a polymeric dielectric and its applications in organic field-effect transistors (OFETs, a polar polymer layer was inserted between two polymethyl methacrylate (PMMA dielectric layers, and its effect on the performance as an organic field-effect transistor (OFET was studied. The OFETs with a sandwiched dielectric layer of poly(vinyl alcohol (PVA or poly(4-vinylphenol (PVP containing hydroxyl groups had shown enhanced characteristics compared to those with only PMMA layers. The field-effect mobility had been raised more than 10 times in n-type devices (three times in the p-type one, and the threshold voltage had been lowered almost eight times in p-type devices (two times in the n-type. The on-off ratio of two kinds of devices had been enhanced by almost two orders of magnitude. This was attributed to the orientation of hydroxyl groups from disordered to perpendicular to the substrate under gate-applied voltage bias, and additional charges would be induced by this polarization at the interface between the semiconductor and dielectrics, contributing to the accumulation of charge transfer.

  14. Large-area WSe2 electric double layer transistors on a plastic substrate

    KAUST Repository

    Funahashi, Kazuma

    2015-04-27

    Due to the requirements for large-area, uniform films, currently transition metal dichalcogenides (TMDC) cannot be used in flexible transistor industrial applications. In this study, we first transferred chemically grown large-area WSe2 monolayer films from the as-grown sapphire substrates to the flexible plastic substrates. We also fabricated electric double layer transistors using the WSe2 films on the plastic substrates. These transistors exhibited ambipolar operation and an ON/OFF current ratio of ∼104, demonstrating chemically grown WSe2 transistors on plastic substrates for the first time. This achievement can be an important first step for the next-generation TMDC based flexible devices. © 2015 The Japan Society of Applied Physics.

  15. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Fan, Ching-Lin; Lai, Hui-Lung; Chang, Jyu-Yu

    2010-05-01

    In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

  16. Ambipolarity in a tokamak with magnetic field ripple

    Science.gov (United States)

    Hazeltine, R. D.

    2016-08-01

    In view of the recognized importance of electrostatic fields regarding turbulent transport, the radial electric field in a tokamak with magnetic field ripple is reconsidered. Terms in the ambipolarity condition involving the radial derivative of the field are derived from an extended drift-kinetic equation, including effects of second order in the gyroradius. Such terms are of interest in part because of their known importance in rotational relaxation equations for the axisymmetric case. The electric field is found to satisfy a nonlinear differential equation that is universal in a certain sense, and that implies spatial relaxation of the potential to its conventionally predicted value.

  17. Effects due to the large ambipolar potential in TMX

    International Nuclear Information System (INIS)

    The large potentials and potential gradients in tandem mirrors have several effects. Some of these are discussed, together with supporting data from TMX. These include: azimuthal averaging by the E x B rotation, reduction of radial outward drifts (from high order multipoles) by the rapid E x B azimuthal velocity, neoclassical-resonant diffusion, Joule heating of central cell ions due to non-ambipolar transport in the radial electric field, low frequency instabilities, and differences between the details of the electron behavior and theory

  18. Light-induced characteristic variations in organic thin-film transistors with a poly(vinylphenol-co-methyl methacrylate)/titanium-dioxide nanocomposite gate dielectric

    Science.gov (United States)

    Kim, Dongwook; Shin, Hyunji; Park, Sangcheol; Lee, Dokyoung; Choi, Jong Sun; Baang, Sungkeun; Ham, Youngjin; Park, Jaehoon; Piao, Shang Hao; Choi, Hyoung Jin

    2015-11-01

    We investigated the effect of light exposure on the electrical characteristics of organic thinfilm transistors (OTFTs) fabricated with a cross-linked poly(vinylphenol-co-methyl methacrylate) (PVP-co-PMMA)/titanium-dioxide (TiO2) nanocomposite gate dielectric. When illuminated, the off-state drain current increased significantly in the OTFTs containing the TiO2 nanocomposite gate dielectric, but changed negligibly in those containing the pristine PVP-co-PMMA gate dielectric. On the other hand, the dependence of the on-state drain current on the photon energy was similar in both cases. These results can be explained in terms of photogenerated charge carriers in the organic semiconductor and the TiO2 nanoparticles.

  19. Exfoliated multilayer MoTe2 field-effect transistors

    Science.gov (United States)

    Fathipour, S.; Ma, N.; Hwang, W. S.; Protasenko, V.; Vishwanath, S.; Xing, H. G.; Xu, H.; Jena, D.; Appenzeller, J.; Seabaugh, A.

    2014-11-01

    The properties of multilayer exfoliated MoTe2 field-effect transistors (FETs) on SiO2 were investigated for channel thicknesses from 6 to 44 monolayers (MLs). All transistors showed p-type conductivity at zero back-gate bias. For channel thicknesses of 8 ML or less, the transistors exhibited ambipolar characteristics. ON/OFF current ratio was greatest, 1 × 105, for the transistor with the thinnest channel, 6 ML. Devices showed a clear photoresponse to wavelengths between 510 and 1080 nm at room temperature. Temperature-dependent current-voltage measurements were performed on a FET with 30 layers of MoTe2. When the channel is turned-on and p-type, the temperature dependence is barrier-limited by the Au/Ti/MoTe2 contact with a hole activation energy of 0.13 eV. A long channel transistor model with Schottky barrier contacts is shown to be consistent with the common-source characteristics.

  20. Origin of mobility enhancement by chemical treatment of gate-dielectric surface in organic thin-film transistors: Quantitative analyses of various limiting factors in pentacene thin films

    Science.gov (United States)

    Matsubara, R.; Sakai, Y.; Nomura, T.; Sakai, M.; Kudo, K.; Majima, Y.; Knipp, D.; Nakamura, M.

    2015-11-01

    For the better performance of organic thin-film transistors (TFTs), gate-insulator surface treatments are often applied. However, the origin of mobility increase has not been well understood because mobility-limiting factors have not been compared quantitatively. In this work, we clarify the influence of gate-insulator surface treatments in pentacene thin-film transistors on the limiting factors of mobility, i.e., size of crystal-growth domain, crystallite size, HOMO-band-edge fluctuation, and carrier transport barrier at domain boundary. We quantitatively investigated these factors for pentacene TFTs with bare, hexamethyldisilazane-treated, and polyimide-coated SiO2 layers as gate dielectrics. By applying these surface treatments, size of crystal-growth domain increases but both crystallite size and HOMO-band-edge fluctuation remain unchanged. Analyzing the experimental results, we also show that the barrier height at the boundary between crystal-growth domains is not sensitive to the treatments. The results imply that the essential increase in mobility by these surface treatments is only due to the increase in size of crystal-growth domain or the decrease in the number of energy barriers at domain boundaries in the TFT channel.

  1. High-performance single-crystalline arsenic-doped indium oxide nanowires for transparent thin-film transistors and active matrix organic light-emitting diode displays.

    Science.gov (United States)

    Chen, Po-Chiang; Shen, Guozhen; Chen, Haitian; Ha, Young-geun; Wu, Chao; Sukcharoenchoke, Saowalak; Fu, Yue; Liu, Jun; Facchetti, Antonio; Marks, Tobin J; Thompson, Mark E; Zhou, Chongwu

    2009-11-24

    We report high-performance arsenic (As)-doped indium oxide (In(2)O(3)) nanowires for transparent electronics, including their implementation in transparent thin-film transistors (TTFTs) and transparent active-matrix organic light-emitting diode (AMOLED) displays. The As-doped In(2)O(3) nanowires were synthesized using a laser ablation process and then fabricated into TTFTs with indium-tin oxide (ITO) as the source, drain, and gate electrodes. The nanowire TTFTs on glass substrates exhibit very high device mobilities (approximately 1490 cm(2) V(-1) s(-1)), current on/off ratios (5.7 x 10(6)), steep subthreshold slopes (88 mV/dec), and a saturation current of 60 microA for a single nanowire. By using a self-assembled nanodielectric (SAND) as the gate dielectric, the device mobilities and saturation current can be further improved up to 2560 cm(2) V(-1) s(-1) and 160 microA, respectively. All devices exhibit good optical transparency (approximately 81% on average) in the visible spectral range. In addition, the nanowire TTFTs were utilized to control green OLEDs with varied intensities. Furthermore, a fully integrated seven-segment AMOLED display was fabricated with a good transparency of 40% and with each pixel controlled by two nanowire transistors. This work demonstrates that the performance enhancement possible by combining nanowire doping and self-assembled nanodielectrics enables silicon-free electronic circuitry for low power consumption, optically transparent, high-frequency devices assembled near room temperature.

  2. Retrieval of Electronic Spectra of Charge Carriers in Organic Field-Effect Transistors from Charge Modulation Reflectance Spectra Distorted by Optical Interference

    Science.gov (United States)

    Miyata, Kiyoshi; Ishino, Yuta; Watanabe, Kazuya; Miwa, Kazumoto; Uemura, Takafumi; Takeya, Jun; Matsumoto, Yoshiyasu

    2013-06-01

    Charge modulation (CM) spectroscopy is useful for detecting and characterizing the electronic structure of charge carriers accumulated in organic field-effect transistors (OFETs). However, CM spectra are distorted by optical interference due to multiple reflections in OFETs particularly when reflection configurations are used. In this study, we demonstrated a method for retrieving the spectra of complex refractive indices of carriers from the distorted CM spectra by using a 4×4 matrix algorithm with general transition matrices. We tested this method by applying it to the CM spectra of a rubrene single-crystal FET measured at several incident angles of light. In spite of the strong distortion of the CM spectra, we could retrieve the spectrum of the imaginary part of refractive indices, which is similar to that observed in the transmission configuration. This method extends the applicability of CM spectroscopy to OFETs with opaque electrodes, where transmission configurations cannot possibly be applied.

  3. Amorphous In-Ga-Zn-O Thin Film Transistor Current-Scaling Pixel Electrode Circuit for Active-Matrix Organic Light-Emitting Displays

    Science.gov (United States)

    Chen, Charlene; Abe, Katsumi; Fung, Tze-Ching; Kumomi, Hideya; Kanicki, Jerzy

    2009-03-01

    In this paper, we analyze application of amorphous In-Ga-Zn-O thin film transistors (a-InGaZnO TFTs) to current-scaling pixel electrode circuit that could be used for 3-in. quarter video graphics array (QVGA) full color active-matrix organic light-emitting displays (AM-OLEDs). Simulation results, based on a-InGaZnO TFT and OLED experimental data, show that both device sizes and operational voltages can be reduced when compare to the same circuit using hydrogenated amorphous silicon (a-Si:H) TFTs. Moreover, the a-InGaZnO TFT pixel circuit can compensate for the drive TFT threshold voltage variation (ΔVT) within acceptable operating error range.

  4. Driving Method for Compensating Reliability Problem of Hydrogenated Amorphous Silicon Thin Film Transistors and Image Sticking Phenomenon in Active Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Shin, Min-Seok; Jo, Yun-Rae; Kwon, Oh-Kyong

    2011-03-01

    In this paper, we propose a driving method for compensating the electrical instability of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs) and the luminance degradation of organic light-emitting diode (OLED) devices for large active matrix OLED (AMOLED) displays. The proposed driving method senses the electrical characteristics of a-Si:H TFTs and OLEDs using current integrators and compensates them by an external compensation method. Threshold voltage shift is controlled a using negative bias voltage. After applying the proposed driving method, the measured error of the maximum emission current ranges from -1.23 to +1.59 least significant bit (LSB) of a 10-bit gray scale under the threshold voltage shift ranging from -0.16 to 0.17 V.

  5. Driving Method Compensating for the Hysteresis of Polycrystalline Silicon Thin-Film Transistors for Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Jung, Myoung-Hoon; Kim, Ohyun; Kim, Byeong-Koo; Chung, Hoon-Ju

    2009-05-01

    A new driving method for active-matrix organic light-emitting diode displays is proposed and evaluated. The pixel structure of the proposed driving method is composed of three thin-film transistors (TFTs) and one capacitor. It inserts black data into display images to reset driving TFTs for the purpose of maintaining constant electrical characteristics of driving TFTs. The proposed driving scheme is less sensitive to the hysteresis of low-temperature polycrystalline silicon (LTPS) TFTs than the conventional pixel structure with two TFTs and one capacitor, and this scheme can virtually eliminate the recoverable residual image that occurs owing to the hysteresis characteristics of LTPS TFTs. In the proposed driving scheme, black data are inserted into displayed images so that the motion image quality is improved.

  6. Transparent Pixel Circuit with Threshold Voltage Compensation Using ZnO Thin-Film Transistors for Active-Matrix Organic Light Emitting Diode Displays

    Science.gov (United States)

    Yang, Ik-Seok; Kwon, Oh-Kyong

    2009-03-01

    A transparent pixel circuit with a threshold voltage compensating scheme using ZnO thin-film transistors (TFTs) for active-matrix organic light emitting diode (AMOLED) displays is proposed. This circuit consists of five n-type ZnO TFTs and two capacitors and can compensate for the threshold voltage variation of ZnO TFTs in real time. From simulation results, the maximum deviation of the emission current of the pixel circuit with a threshold voltage variation of ±1 V is determined to be less than 10 nA. From measurement results, it is verified that the maximum deviation of measured emission currents with measurement position in a glass substrate is less than 15 nA in a higher current range, and the deviation of emission current with time is less than 3%.

  7. Unique Characteristics of Vertical Carbon Nanotube Field-effect Transistors on Silicon

    KAUST Repository

    Li, Jingqi

    2014-07-01

    A vertical carbon nanotube field-effect transistor (CNTFET) based on silicon (Si) substrate has been proposed and simulated using a semi-classical theory. A single-walled carbon nanotube (SWNT) and an n-type Si nanowire in series construct the channel of the transistor. The CNTFET presents ambipolar characteristics at positive drain voltage (Vd) and n-type characteristics at negative Vd. The current is significantly influenced by the doping level of n-Si and the SWNT band gap. The n-branch current of the ambipolar characteristics increases with increasing doping level of the n-Si while the p-branch current decreases. The SWNT band gap has the same influence on the p-branch current at a positive Vd and n-type characteristics at negative Vd. The lower the SWNT band gap, the higher the current. However, it has no impact on the n-branch current in the ambipolar characteristics. Thick oxide is found to significantly degrade the current and the subthreshold slope of the CNTFETs.

  8. Improved Performance of Organic Thin Film Transistor with an Inorganic Oxide/Polymer Double-Layer Insulator

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi-Hua; DONG Gui-Fang; WANG Li-Duo; QIU Yong

    2007-01-01

    We employ the Ta2O5/PVP (poly-4-vinylphenol) double-layer gate insulator to improve the performance of pentacene thin-film transistors. It is found that the double-layer insulator has low leakage current, smooth surface and considerably high capacitance. Compared to Ta2O5 insulator layers, the device with the Ta2O5/PVP double-layer insulator exhibits an enhancement of the Reid-effect mobility from 0.21 to 0.54 cm2 /Vs, and the decreasing threshold voltage from 4.38V to -2.5 V. The results suggest that the Ta2O5/PVP double-layer insulator is a potential gate insulator for fabricating OTFTs with good electrical performance.

  9. High-conductance low-voltage organic thin film transistor with locally rearranged poly(3-hexylthiophene) domain by current annealing on plastic substrate

    Science.gov (United States)

    Pei, Zingway; Tsai, Hsing-Wang; Lai, Hsin-Cheng

    2016-02-01

    The organic material based thin film transistors (TFTs) are attractive for flexible optoelectronics applications due to the ability of lager area fabrication by solution and low temperature process on plastic substrate. Recently, the research of organic TFT focus on low operation voltage and high output current to achieve a low power organic logic circuit for optoelectronic device,such as e-paper or OLED displayer. To obtain low voltage and high output current, high gate capacitance and high channel mobility are key factors. The well-arranged polymer chain by a high temperature postannealing, leading enhancement conductivity of polymer film was a general method. However, the thermal annealing applying heat for all device on the substrate and may not applicable to plastic substrate. Therefore, in this work, the low operation voltage and high output current of polymer TFTs was demonstrated by locally electrical bias annealing. The poly(styrene-comethyl methacrylate) (PS-r-PMMA) with ultra-thin thickness is used as gate dielectric that the thickness is controlled by thermal treatment after spin coated on organic electrode. In electrical bias-annealing process, the PS-r- PMMA is acted a heating layer. After electrical bias-annealing, the polymer TFTs obtain high channel mobility at low voltage that lead high output current by a locally annealing of P3HT film. In the future, the locally electrical biasannealing method could be applied on plastic substrate for flexible optoelectronic application.

  10. Turbulent energy dissipation and intermittency in ambipolar diffusion magnetohydrodynamics

    CERN Document Server

    Momferratos, Georgios; Falgarone, Edith; Forêts, Guillaume Pineau des

    2015-01-01

    The dissipation of kinetic and magnetic energy in the interstellar medium (ISM) can proceed through viscous, Ohmic or ambipolar diffusion (AD). It occurs at very small scales compared to the scales at which energy is presumed to be injected. This localized heating may impact the ISM evolution but also its chemistry, thus providing observable features. Here, we perform 3D spectral simulations of decaying magnetohydrodynamic turbulence including the effects of AD. We find that the AD heating power spectrum peaks at scales in the inertial range, due to a strong alignment of the magnetic and current vectors in the dissipative range. AD affects much greater scales than the AD scale predicted by dimensional analysis. We find that energy dissipation is highly concentrated on thin sheets. Its probability density function follows a lognormal law with a power-law tail which hints at intermittency, a property which we quantify by use of structure function exponents. Finally, we extract structures of high dissipation, de...

  11. Ambipolarity and transport with resonant ion diffusion in EBT

    International Nuclear Information System (INIS)

    Using recently derived analytic expressions for resonant and nonresonant neoclassical transport coefficients in EBT, we calculate the ambipolar potential required to maintain quasi-charge neutrality in the presence of a high-energy ion tail produced by nonclassical heating. The electric field obeys a differential rather than an algebraic equation. Solution of this equation gives a potential proportional to the local magnetic field strength and thus a rigid rotation of low-energy ions near the magnetic axis. Radial-transport calculations using this potential give improved agreement with experimental data for neutral density and particle lifetime. However, high-energy ion orbits in the calculated potential exhibit banana widths larger than assumed in the resonant transport theory. The required density of high-energy ions is therefore larger than would be expected if realistic banana widths could be included

  12. Surface Morphology of Polyimide Thin Film Dip-Coated on Polyester Filament for Dielectric Layer in Fibrous Organic Field Effect Transistor

    Directory of Open Access Journals (Sweden)

    Rambausek Lina

    2014-09-01

    Full Text Available The idea of wearable electronics automatically leads to the concept of integrating electronic functions on textile substrates. Since this substrate type implies certain challenges in comparison with their rigid electronic companions, it is of utmost importance to investigate the application of materials for generating the electronic functions on the textile substrate. Only when interaction of materials and textile substrate is fully understood, the electronic function can be generated on the textile without changing the textile’s properties, being flexible or stretchable. This research deals with the optimization of the dielectric layer in a fibrous organic field effect transistor (OFET. A transistor can act as an electrical switch in a circuit. In this work, the polyimide layer was dip-coated on a copper-coated polyester filament. After thoroughly investigating the process conditions, best results with minimal thickness and roughness at full insulation could be achieved at a dip-coating speed of 50 mm/min. The polyimide solution was optimal at 15w% and the choice for the solvent NMP was made. In this paper, details on the pre-treatment methods, choice of solvent and dip-coating speed and their effect on layer morphology and thickness, electrical properties and roughness are reported. Results show that the use of polyimide as a dielectric layer in the architecture of a fibrous OFET is promising. Further research deals with the application of the semiconductor layer within the mentioned architecture, to finally build an OFET on a filament for application in smart textiles.

  13. High-performance single-crystalline arsenic-doped indium oxide nanowires for transparent thin-film transistors and active matrix organic light-emitting diode displays.

    Science.gov (United States)

    Chen, Po-Chiang; Shen, Guozhen; Chen, Haitian; Ha, Young-geun; Wu, Chao; Sukcharoenchoke, Saowalak; Fu, Yue; Liu, Jun; Facchetti, Antonio; Marks, Tobin J; Thompson, Mark E; Zhou, Chongwu

    2009-11-24

    We report high-performance arsenic (As)-doped indium oxide (In(2)O(3)) nanowires for transparent electronics, including their implementation in transparent thin-film transistors (TTFTs) and transparent active-matrix organic light-emitting diode (AMOLED) displays. The As-doped In(2)O(3) nanowires were synthesized using a laser ablation process and then fabricated into TTFTs with indium-tin oxide (ITO) as the source, drain, and gate electrodes. The nanowire TTFTs on glass substrates exhibit very high device mobilities (approximately 1490 cm(2) V(-1) s(-1)), current on/off ratios (5.7 x 10(6)), steep subthreshold slopes (88 mV/dec), and a saturation current of 60 microA for a single nanowire. By using a self-assembled nanodielectric (SAND) as the gate dielectric, the device mobilities and saturation current can be further improved up to 2560 cm(2) V(-1) s(-1) and 160 microA, respectively. All devices exhibit good optical transparency (approximately 81% on average) in the visible spectral range. In addition, the nanowire TTFTs were utilized to control green OLEDs with varied intensities. Furthermore, a fully integrated seven-segment AMOLED display was fabricated with a good transparency of 40% and with each pixel controlled by two nanowire transistors. This work demonstrates that the performance enhancement possible by combining nanowire doping and self-assembled nanodielectrics enables silicon-free electronic circuitry for low power consumption, optically transparent, high-frequency devices assembled near room temperature. PMID:19842677

  14. EDITORIAL: Reigniting innovation in the transistor Reigniting innovation in the transistor

    Science.gov (United States)

    Demming, Anna

    2012-09-01

    behaviour in devices fabricated from chemically reduced graphene oxide. The work provided an important step forward for graphene electronics, which has been hampered by difficulties in scaling up the mechanical exfoliation techniques required to produce the high-quality graphene often needed for functioning devices [8]. In Sweden, researchers have developed a transistor design that they fabricate using standard III-V parallel processing, which also has great promise for scaling up production. Their transistor is based on a vertical array of InAs nanowires, which provide high electron mobility and the possibility of high-speed and low-power operation [9]. Different fabrication techniques and design parameters can influence the properties of transistors. Researchers in Belgium used a new method based on high-vacuum scanning spreading resistance microscopy to study the effect of diameter on carrier profile in nanowire transistors [10]. They then used experimental data and simulations to gain a better understanding of how this influenced the transistor performance. In Japan, Y Ohno and colleagues at Nagoya University have reported how atomic layer deposition of an insulating layer of HfO2 on carbon nanotube field effect transistors can change the carrier from p-type to n-type [11]. Carrier type switching—'ambipolar behaviour'—and hysteresis of carbon nanotube network transistors can make achieving reliable device performance challenging. However studies have also suggested that the hysteretic properties may be exploited in non-volatile memory applications. A collaboration of researchers in Italy and the US demonstrated transistor and memory cell behaviour in a system based on a carbon nanotube network [13]. Their device had relatively fast programming, good endurance and the charge retention was successfully enhanced by limiting exposure to air. Progress in understanding transistor behaviour has inspired other innovations in device applications. Nanowires are notoriously

  15. Enhanced mobility in organic field-effect transistors due to semiconductor/dielectric iInterface control and very thin single crystal.

    Science.gov (United States)

    Dong, Ji; Yu, Peng; Arabi, Syeda Atika; Wang, Jiawei; He, Jun; Jiang, Chao

    2016-07-01

    A perfect organic crystal while keeping high quality semiconductor/dielectric interface with minimal defects and disorder is crucial for the realization of high performance organic single crystal field-effect transistors (OSCFETs). However, in most reported OSCFET devices, the crystal transfer processes is extensively used. Therefore, the semiconductor/dielectric interface is inevitably damaged. Carrier traps and scattering centers are brought into the conduction channel, so that the intrinsic high mobility of OSCFET devices is entirely disguised. Here, very thin pentacene single crystal is grown directly on bare SiO2 by developing a 'seed-controlled' pentacene single crystal method. The interface quality is controlled by an in situ fabrication of OSCFETs. The interface is kept intact without any transfer process. Furthermore, we quantitatively analyze the influence of crystal thickness on device performance. With a pristine interface and very thin crystal, we have achieved the highest mobility: 5.7 cm(2) V(-1) s(-1)-more than twice the highest ever reported pentacene OSCFET mobility on bare SiO2. This study may provide a universal route for the use of small organic molecules to achieve high performance in lamellar single crystal field-effect devices. PMID:27211506

  16. Current on-off operation of graphene transistor with dual gates and He ion irradiated channel

    Energy Technology Data Exchange (ETDEWEB)

    Nakaharai, Shu; Sato, Shintaro; Yokoyama, Naoki [Green Nanoelectronics Centre, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 305-8569 (Japan); Iijima, Tomohiko [Innovation Center for Advanced Nanodevices, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 305-8569 (Japan); Ogawa, Shinichi [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 305-8569 (Japan); Li, Song-Lin; Tsukagoshi, Kazuhito [International Centre for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2013-11-15

    We demonstrate the current on-off operation in a novel dual-gated transistor with a He ion irradiated graphene channel in which defect-induced transport gap is formed. The transistor operation was performed by controlling the band configuration of gate-controlled p-i-n junction by independent biasing of top gates. The maximum current on-off ratio of nearly four orders of magnitude was obtained at a temperature of 250 K in the proposed device structure. It was also demonstrated that the transistor polarity can be changed between unipolar and ambipolar just by adjusting the gate bias of one of the dual gates, as expected from the device operation model. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Ambipolar Diffusion in Direct-Current Positive Column with Variations in Radius of Discharge Tube

    Institute of Scientific and Technical Information of China (English)

    D. AKBAR; S. BILIKMEN

    2006-01-01

    @@ The ambipolar diffusion and argon ion mobility as functions of the reduced electric field and pressure times the tube radius are investigated in a weakly ionized non-uniform glow discharge plasma system.

  18. Ambipolar diffusion regulated collapse of filaments threaded by perpendicular magnetic fields

    CERN Document Server

    Burge, C A; Falle, S A E G; Hartquist, T W

    2016-01-01

    We numerically reproduce the density profiles for filaments that are in magnetohydrostatic and pressure equilibrium with their surroundings obtained in Tomisaka (2014) and show that these equilibria are dynamically stable. If the effect of ambipolar diffusion is considered, these filaments lose magnetic support initiating cloud collapse. The filaments do not lose magnetic flux. Rather the magnetic flux is redistributed within the filament from the centre towards the envelope. The rate of the collapse is inversely proportional to the fractional ionisation and two gravitationally-driven ambipolar diffusion regimes for the collapse are observed as predicted in Mouschovias & Morton (1991). For high values of the ionisation coefficient, that is $X \\geq 10^{-7}$, the gas is strongly coupled to the magnetic field and the Jeans length is larger than the ambipolar diffusion length scale. Then the collapse is governed by magnetically-regulated ambipolar diffusion. For $X \\lesssim 10^{-8}$, the gas is weakly coupled...

  19. Evolution of views on the structure of the ambipolar electric field in toroidal magnetic confinement systems

    Energy Technology Data Exchange (ETDEWEB)

    Kovrizhnykh, L. M., E-mail: lmkov@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2015-12-15

    Various methods of determining the ambipolar electric field in toroidal magnetic systems (predominantly, in stellarators) and the evolution of views on this problem are discussed. Paradoxes encountered in solving this problem are analyzed, and ways of resolving them are proposed.

  20. Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

    Science.gov (United States)

    Truong, Minh Anh

    2016-01-01

    Summary Ladder-type π-conjugated compounds containing a benzo[2,1-b:3,4-b']difuran skeleton, such as dibenzo[d,d']benzo[2,1-b:3,4-b']difuran (syn-DBBDF) and dinaphtho[2,3-d:2',3'-d']benzo[2,1-b:3,4-b']difuran (syn-DNBDF) were synthesized. Their photophysical and electrochemical properties were revealed by UV–vis absorption and photoluminescence spectroscopy and cyclic voltammetry. Organic field-effect transistors (OFETs) were fabricated with these compounds as organic semiconductors, and their semiconducting properties were evaluated. OFETs with syn-DBBDF and syn-DNBDF showed typical p-type characteristics with hole mobilities of <1.5 × 10−3 cm2·V−1·s−1 and <1.0 × 10−1 cm2·V−1·s−1, respectively. PMID:27340471

  1. Flexible non-volatile optical memory thin-film transistor device with over 256 distinct levels based on an organic bicomponent blend

    Science.gov (United States)

    Leydecker, Tim; Herder, Martin; Pavlica, Egon; Bratina, Gvido; Hecht, Stefan; Orgiu, Emanuele; Samorì, Paolo

    2016-09-01

    Organic nanomaterials are attracting a great deal of interest for use in flexible electronic applications such as logic circuits, displays and solar cells. These technologies have already demonstrated good performances, but flexible organic memories are yet to deliver on all their promise in terms of volatility, operational voltage, write/erase speed, as well as the number of distinct attainable levels. Here, we report a multilevel non-volatile flexible optical memory thin-film transistor based on a blend of a reference polymer semiconductor, namely poly(3-hexylthiophene), and a photochromic diarylethene, switched with ultraviolet and green light irradiation. A three-terminal device featuring over 256 (8 bit storage) distinct current levels was fabricated, the memory states of which could be switched with 3 ns laser pulses. We also report robustness over 70 write-erase cycles and non-volatility exceeding 500 days. The device was implemented on a flexible polyethylene terephthalate substrate, validating the concept for integration into wearable electronics and smart nanodevices.

  2. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors

    Science.gov (United States)

    Wang, Chao; Lee, Wen-Ya; Kong, Desheng; Pfattner, Raphael; Schweicher, Guillaume; Nakajima, Reina; Lu, Chien; Mei, Jianguo; Lee, Tae Hoon; Wu, Hung-Chin; Lopez, Jeffery; Diao, Ying; Gu, Xiaodan; Himmelberger, Scott; Niu, Weijun; Matthews, James R.; He, Mingqian; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan

    2015-12-01

    Both high gain and transconductance at low operating voltages are essential for practical applications of organic field-effect transistors (OFETs). Here, we describe the significance of the double-layer capacitance effect in polar rubbery dielectrics, even when present in a very low ion concentration and conductivity. We observed that this effect can greatly enhance the OFET transconductance when driven at low voltages. Specifically, when the polar elastomer poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) was used as the dielectric layer, despite a thickness of several micrometers, we obtained a transconductance per channel width 30 times higher than that measured for the same organic semiconductors fabricated on a semicrystalline PVDF-HFP with a similar thickness. After a series of detailed experimental investigations, we attribute the above observation to the double-layer capacitance effect, even though the ionic conductivity is as low as 10-10 S/cm. Different from previously reported OFETs with double-layer capacitance effects, our devices showed unprecedented high bias-stress stability in air and even in water.

  3. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2014-01-01

    Full Text Available This paper proposes a novel pixel circuit design and driving method for active-matrix organic light-emitting diode (AM-OLED displays that use low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs as driving element. The automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE simulator was used to verify that the proposed pixel circuit, which comprises five transistors and one capacitor, can supply uniform output current. The voltage programming method of the proposed pixel circuit comprises three periods: reset, compensation with data input, and emission periods. The simulated results reflected excellent performance. For instance, when ΔVTH=±0.33 V, the average error rate of the OLED current variation was low (<0.8%, and when ΔVTH_OLED=+0.33 V, the error rate of the OLED current variation was 4.7%. Moreover, when the I×R (current × resistance drop voltage of a power line was 0.3 V, the error rate of the OLED current variation was 5.8%. The simulated results indicated that the proposed pixel circuit exhibits high immunity to the threshold voltage deviation of both the driving poly-Si TFTs and OLEDs, and simultaneously compensates for the I×R drop voltage of a power line.

  4. 25th anniversary article: progress in chemistry and applications of functional indigos for organic electronics.

    Science.gov (United States)

    Głowacki, Eric Daniel; Voss, Gundula; Sariciftci, Niyazi Serdar

    2013-12-17

    Indigo and its derivatives are dyes and pigments with a long and distinguished history in organic chemistry. Recently, applications of this 'old' structure as a functional organic building block for organic electronics applications have renewed interest in these molecules and their remarkable chemical and physical properties. Natural-origin indigos have been processed in fully bio-compatible field effect transistors, operating with ambipolar mobilities up to 0.5 cm(2) /Vs and air-stability. The synthetic derivative isoindigo has emerged as one of the most successful building-blocks for semiconducting polymers for plastic solar cells with efficiencies > 5%. Another isomer of indigo, epindolidione, has also been shown to be one of the best reported organic transistor materials in terms of mobility (∼2 cm(2) /Vs) and stability. This progress report aims to review very recent applications of indigoids in organic electronics, but especially to logically bridge together the hereto independent research directions on indigo, isoindigo, and other materials inspired by historical dye chemistry: a field which was the root of the development of modern chemistry in the first place.

  5. Protonic transistors from thin reflecting films

    International Nuclear Information System (INIS)

    Ionic transistors from organic and biological materials hold great promise for bioelectronics applications. Thus, much research effort has focused on optimizing the performance of these devices. Herein, we experimentally validate a straightforward strategy for enhancing the high to low current ratios of protein-based protonic transistors. Upon reducing the thickness of the transistors’ active layers, we increase their high to low current ratios 2-fold while leaving the other figures of merit unchanged. The measured ratio of 3.3 is comparable to the best values found for analogous devices. These findings underscore the importance of the active layer geometry for optimum protonic transistor functionality

  6. Label-free C-reactive protein electronic detection with an electrolyte-gated organic field-effect transistor-based immunosensor.

    Science.gov (United States)

    Magliulo, Maria; De Tullio, Donato; Vikholm-Lundin, Inger; Albers, Willem M; Munter, Tony; Manoli, Kyriaki; Palazzo, Gerardo; Torsi, Luisa

    2016-06-01

    In this contribution, we propose a label-free immunosensor, based on a novel type of electrolyte-gated field-effect transistor (EGOFET), for ultrasensitive detection of the C-reactive protein (CRP). The recognition layer of the biosensor is fabricated by physical adsorption of the anti-CRP monoclonal antibody onto a poly-3-hexyl thiophene (P3HT) organic semiconductor surface. A supplementary nonionic hydrophilic polymer is used as a blocking agent preventing nonspecific interactions and allowing a better orientation of the antibodies immobilized onto the P3HT surface. The whole biomolecule immobilization procedure does not require any pretreatment of the organic semiconductor surface, and the whole functionalization process is completed in less than 30 min. Surface plasmon resonance (SPR) measurements were performed to assess the amount of biomolecules physisorbed onto the P3HT and to evaluate the CRP binding proprieties of the deposited anti-CRP layer. A partial surface coverage of about 23 % of adsorbed antibody molecules was found to most efficiently sense the CRP. The electrical performance of the EGOFET immunosensor was comparable to that of a bare P3HT EGOFET device, and the obtained CRP calibration curve was linear over six orders of magnitude (from 4 pM to 2 μM). The relative standard deviation of the individual calibration points, measured on immunosensors fabricated on different chips, ranged between 1 and 14 %, and a detection limit of 2 pM (220 ng/L) was established. The novel electronic immunosensor is compatible with low-cost fabrication procedures and was successfully employed for the detection of the CRP biomarker in the clinically relevant matrix serum. Graphical abstract Schematic of the EGOFET immunosensor for CRP detection. The anti-CRP monoclonal antibody layer is physisorbed on the P3HT organic semiconductor and the CRP is directly measured by a label-free electronic EGOFET transducer. PMID:27032409

  7. Influence of the substrate platform on the opto-electronic properties of multi-layer organic light-emitting field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Generali, Gianluca; Capelli, Raffaella; Toffanin, Stefano; Muccini, Michele [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna (Italy); Dinelli, Franco, E-mail: g.generali@bo.ismn.cnr.it, E-mail: m.muccini@bo.ismn.cnr.it [Consiglio Nazionale delle Ricerche (CNR), INO U.O.S. ' A. Gozzini' Area della Ricerca di Pisa - S. Cataldo, via Moruzzi 1, I-56124 Pisa (Italy)

    2011-06-08

    In this paper, we present a study of the effects of the influence of the substrate platform on the properties of a three-layer vertical hetero-junction made of thin films of {alpha}, {omega}-diperfluorohexyl-4T (DHF4T), a blend of tris(8-hydroxyquinoline)aluminium (Alq3) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) and {alpha}, {omega}-dihexyl-quaterthiophene (DH4T). The hetero-junction represents the active component of an organic light-emitting transistor (OLET). The substrate platforms investigated in this study are glass/indium-tin-oxide/poly(methyl-methacrylate) (PMMA) and Si{sup ++}/silicon oxide (SiO{sub 2})/PMMA. The first platform is almost completely transparent to light and therefore is very promising for use in OLET applications. The second one has been chosen for comparison as it employs standard microelectronic materials, i.e. Si{sup ++}/SiO{sub 2}. We show how different gate materials and structure can affect the relevant field-effect electrical characteristics, such as the charge mobility and threshold voltage. By means of an atomic force microscopy analysis, a systematic study has been made in order to correlate the morphology of the active layers with the electrical properties of the devices.

  8. Demonstration of InAlN/AlGaN high electron mobility transistors with an enhanced breakdown voltage by pulsed metal organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xue, JunShuai, E-mail: junshuaixue@hotmail.com; Zhang, JinCheng; Hao, Yue [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2016-01-04

    In this work, InAlN/AlGaN heterostructures employing wider bandgap AlGaN instead of conventional GaN channel were grown on sapphire substrate by pulsed metal organic chemical vapor deposition, where the nominal Al composition in InAlN barrier and AlGaN channel were chosen to be 83% and 5%, respectively, to achieve close lattice-matched condition. An electron mobility of 511 cm{sup 2}/V s along with a sheet carrier density of 1.88 × 10{sup 13 }cm{sup −2} were revealed in the prepared heterostructures, both of which were lower compared with lattice-matched InAlN/GaN due to increased intrinsic alloy disorder scattering resulting from AlGaN channel and compressively piezoelectric polarization in barrier, respectively. While the high electron mobility transistor (HEMT) processed on these structures not only exhibited a sufficiently high drain output current density of 854 mA/mm but also demonstrated a significantly enhanced breakdown voltage of 87 V, which is twice higher than that of reported InAlN/GaN HEMT with the same device dimension, potential characteristics for high-voltage operation of GaN-based electronic devices.

  9. Demonstration of InAlN/AlGaN high electron mobility transistors with an enhanced breakdown voltage by pulsed metal organic chemical vapor deposition

    Science.gov (United States)

    Xue, JunShuai; Zhang, JinCheng; Hao, Yue

    2016-01-01

    In this work, InAlN/AlGaN heterostructures employing wider bandgap AlGaN instead of conventional GaN channel were grown on sapphire substrate by pulsed metal organic chemical vapor deposition, where the nominal Al composition in InAlN barrier and AlGaN channel were chosen to be 83% and 5%, respectively, to achieve close lattice-matched condition. An electron mobility of 511 cm2/V s along with a sheet carrier density of 1.88 × 1013 cm-2 were revealed in the prepared heterostructures, both of which were lower compared with lattice-matched InAlN/GaN due to increased intrinsic alloy disorder scattering resulting from AlGaN channel and compressively piezoelectric polarization in barrier, respectively. While the high electron mobility transistor (HEMT) processed on these structures not only exhibited a sufficiently high drain output current density of 854 mA/mm but also demonstrated a significantly enhanced breakdown voltage of 87 V, which is twice higher than that of reported InAlN/GaN HEMT with the same device dimension, potential characteristics for high-voltage operation of GaN-based electronic devices.

  10. High reliable and stable organic field-effect transistor nonvolatile memory with a poly(4-vinyl phenol) charge trapping layer based on a pn-heterojunction active layer

    Science.gov (United States)

    Xiang, Lanyi; Ying, Jun; Han, Jinhua; Zhang, Letian; Wang, Wei

    2016-04-01

    In this letter, we demonstrate a high reliable and stable organic field-effect transistor (OFET) based nonvolatile memory (NVM) with a polymer poly(4-vinyl phenol) (PVP) as the charge trapping layer. In the unipolar OFETs, the inreversible shifts of the turn-on voltage (Von) and severe degradation of the memory window (ΔVon) at programming (P) and erasing (E) voltages, respectively, block their application in NVMs. The obstacle is overcome by using a pn-heterojunction as the active layer in the OFET memory, which supplied a holes and electrons accumulating channel at the supplied P and E voltages, respectively. Both holes and electrons transferring from the channels to PVP layer and overwriting the trapped charges with an opposite polarity result in the reliable bidirectional shifts of Von at P and E voltages, respectively. The heterojunction OFET exhibits excellent nonvolatile memory characteristics, with a large ΔVon of 8.5 V, desired reading (R) voltage at 0 V, reliable P/R/E/R dynamic endurance over 100 cycles and a long retention time over 10 years.

  11. Chalcogenophene comonomer comparison in small band gap diketopyrrolopyrrole-based conjugated polymers for high-performing field-effect transistors and organic solar cells

    KAUST Repository

    Ashraf, Raja Shahid

    2015-01-28

    The design, synthesis, and characterization of a series of diketopyrrolopyrrole-based copolymers with different chalcogenophene comonomers (thiophene, selenophene, and tellurophene) for use in field-effect transistors and organic photovoltaic devices are reported. The effect of the heteroatom substitution on the optical, electrochemical, and photovoltaic properties and charge carrier mobilities of these polymers is discussed. The results indicate that by increasing the size of the chalcogen atom (S < Se < Te), polymer band gaps are narrowed mainly due to LUMO energy level stabilization. In addition, the larger heteroatomic size also increases intermolecular heteroatom-heteroatom interactions facilitating the formation of polymer aggregates leading to enhanced field-effect mobilities of 1.6 cm2/(V s). Bulk heterojunction solar cells based on the chalcogenophene polymer series blended with fullerene derivatives show good photovoltaic properties, with power conversion efficiencies ranging from 7.1-8.8%. A high photoresponse in the near-infrared (NIR) region with excellent photocurrents above 20 mA cm-2 was achieved for all polymers, making these highly efficient low band gap polymers promising candidates for use in tandem solar cells. (Graph Presented).

  12. Electrical characteristics of top contact pentacene organic thin film transistors with SiO2 and poly(methyl methacrylate) as gate dielectrics

    Indian Academy of Sciences (India)

    Jaya Lohani; Praveen Saho; Upender Kumar; V R Balakrishnan; P K Basu

    2008-09-01

    Organic thin film transistors (OTFTs) were fabricated using pentacene as the active layer with two different gate dielectrics, namely SiO2 and poly(methyl methacrylate) (PMMA), in top contact geometry for comparative studies. OTFTs with SiO2 as dielectric and gold deposited on the rough side of highly doped silicon (n+ -Si) as gate electrode exhibited reasonable field effect mobilities. To deal with poor stability and large leakage currents between source/drain and gate electrodes in these devices, isolated OTFTs with reduced source/drain contact area were fabricated by selective deposition of pentacene on SiO2/PMMA through shadow mask. This led to almost negligible leakage currents and no degradation in electrical performance even after 14 days of storage under ambient conditions. But, the field effect mobilities obtained were lower than 10-3 cm2 V-1 s-1, whereas by using PMMA as gate dielectric with chromium deposited on the polished side of n+ -Si as gate electrode, improved field effect mobilities (> 0.02 cm2 V-1 s-1) were obtained. PMMA-based OTFTs also exhibited lower leakage currents and reproducible output characteristics even after 30 days of storage under ambient conditions.

  13. Effects of neutral particle beam on nano-crystalline silicon thin films, with application to thin film transistor backplane for flexible active matrix organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Nyoung; Song, Byoung Chul; Lee, Dong Hyeok [Dept. of Display and Semiconductor Physics, Korea University, Chungnam (Korea, Republic of); Yoo, Suk Jae; Lee, Bonju [National Fusion Research Institute, 52, Yuseong-Gu, Deajeon, 305-333 (Korea, Republic of); Hong, MunPyo, E-mail: goodmoon@korea.ac.kr [Dept. of Display and Semiconductor Physics, Korea University, Chungnam (Korea, Republic of)

    2011-08-01

    A novel deposition process for nano-crystalline silicon (nc-Si) thin films was developed using neutral beam assisted chemical vapor deposition (NBaCVD) technology for the application of the thin film transistor (TFT) backplane of flexible active matrix organic light emitting diode (AMOLED). During the formation of a nc-Si thin film, the energetic particles enhance nano-sized crystalline rather microcrystalline Si in thin films. Neutral Particle Beam (NPB) affects the crystallinity in two ways: (1) NPB energy enhances nano-crystallinity through kinetic energy transfer and chemical annealing, and (2) heavier NPB (such as Ar) induces damage and amorphization through energetic particle impinging. Nc-Si thin film properties effectively can be changed by the reflector bias. As increase of NPB energy limits growing the crystalline, the performance of TFT supports this NPB behavior. The results of nc-Si TFT by NBaCVD demonstrate the technical potentials of neutral beam based processes for achieving high stability and reduced leakage in TFT backplanes for AMOLEDs.

  14. Gate dielectric surface treatments for performance improvement of poly(3-hexylthiophene-2,5-diyl) based organic field-effect transistors

    Science.gov (United States)

    Nawaz, Ali; de, Cristiane, , Col; Cruz-Cruz, Isidro; Kumar, Anshu; Kumar, Anil; Hümmelgen, Ivo A.

    2015-08-01

    We report on enhanced performance in poly(3-hexylthiophene-2,5-diyl) (P3HT) based organic field effect transistors (OFETs) achieved by improvement in hole transport along the channel near the insulator/semiconductor (I/S) interface. The improvement in hole transport is demonstrated to occur very close to the I/S interface, after treatment of the insulator layer with sodium dodecyl sulfate (SDS). SDS is an anionic surfactant, with negatively charged heads, known for formation of micelles above critical micelle concentration (CMC), which contribute to the passivation of positively charged traps. Investigation of field-effect mobility (μFET) as a function of channel bottleneck thickness in OFETs reveals the favorable gate voltage regime where mobility is the highest. In addition, it shows that the gate dielectric surface treatment not only leads to an increase in mobility in that regime, but also displaces charge transport closer to the interface, hence pointing toward passivation of the charge traps at I/S interface. OFETs with SDS treatment were compared with untreated and vitamin C or hexadecyltrimethylammonium bromide (CTAB) treated OFETs. All the treatments resulted in significant improvements in specific dielectric capacitance, μFET, on/off current ratio and transconductance.

  15. Ambipolar field effect in the ternary topological insulator (BixSb1–x)2Te3 by composition tuning

    KAUST Repository

    Kong, Desheng

    2011-10-02

    Topological insulators exhibit a bulk energy gap and spin-polarized surface states that lead to unique electronic properties 1-9, with potential applications in spintronics and quantum information processing. However, transport measurements have typically been dominated by residual bulk charge carriers originating from crystal defects or environmental doping 10-12, and these mask the contribution of surface carriers to charge transport in these materials. Controlling bulk carriers in current topological insulator materials, such as the binary sesquichalcogenides Bi 2Te 3, Sb 2Te 3 and Bi 2Se 3, has been explored extensively by means of material doping 8,9,11 and electrical gating 13-16, but limited progress has been made to achieve nanostructures with low bulk conductivity for electronic device applications. Here we demonstrate that the ternary sesquichalcogenide (Bi xSb 1-x) 2Te 3 is a tunable topological insulator system. By tuning the ratio of bismuth to antimony, we are able to reduce the bulk carrier density by over two orders of magnitude, while maintaining the topological insulator properties. As a result, we observe a clear ambipolar gating effect in (Bi xSb 1-x) 2Te 3 nanoplate field-effect transistor devices, similar to that observed in graphene field-effect transistor devices 17. The manipulation of carrier type and density in topological insulator nanostructures demonstrated here paves the way for the implementation of topological insulators in nanoelectronics and spintronics. © 2011 Macmillan Publishers Limited. All rights reserved.

  16. Graphene transistors via in situ voltage-induced reduction of graphene-oxide under ambient conditions.

    Science.gov (United States)

    Mativetsky, Jeffrey M; Liscio, Andrea; Treossi, Emanuele; Orgiu, Emanuele; Zanelli, Alberto; Samorì, Paolo; Palermo, Vincenzo

    2011-09-14

    Here, we describe a simple approach to fabricate graphene-based field-effect-transistors (FETs), starting from aqueous solutions of graphene-oxide (GO), processed entirely under ambient conditions. The process relies on the site-selective reduction of GO sheets deposited in between or on the surface of micro/nanoelectrodes. The same electrodes are first used for voltage-induced electrochemical GO reduction, and then as the source and drain contacts of FETs, allowing for the straightforward production and characterization of ambipolar graphene devices. With the use of nanoelectrodes, we could reduce different selected areas belonging to one single sheet as well.

  17. Amorphous Solid Simulation and Trial Fabrication of the Organic Field-Effect Transistor of Tetrathienonaphthalenes Prepared by Using Microflow Photochemical Reactions: A Theoretical Calculation-Inspired Investigation.

    Science.gov (United States)

    Yamamoto, Atsushi; Matsui, Yasunori; Asada, Toshio; Kumeda, Motoki; Takagi, Kenichiro; Suenaga, Yu; Nagae, Kunihiko; Ohta, Eisuke; Sato, Hiroyasu; Koseki, Shiro; Naito, Hiroyoshi; Ikeda, Hiroshi

    2016-04-15

    The p-type organic semiconductor (OSC) material tetrathieno[2,3-a:3',2'-c:2″,3″-f:3‴,2‴-h]naphthalene (2TTN) and its alkyl-substituted derivatives C(n)-2TTNs (n = 6, 8, and 10) have been developed based on the results of theoretical calculation-inspired investigation. A hole mobility for amorphous C(n)-2TTNs (10(-2)-10(-3) cm(2) V(-1) s(-1)) was accurately predicted by using a novel statistical method in which the geometric mean of the mobilities for many individual small molecular flocks in an amorphous solid was obtained by using molecular mechanical molecular dynamics simulations and quantum chemical calculations. The simulation also suggests that upon increasing the length of alkyl chains in C(n)-2TTNs the mobilities become smaller as a consequence of a decrease in transfer integral values. C(n)-2TTNs are synthesized in a microflow reactor through photoreactions of the corresponding precursors. C(n)-2TTNs are then utilized in the fabrication of organic field-effect transistors (OFETs). Although spin-coated thin films of C(n)-2TTNs are crystalline, the hole mobilities (10(-2)-10(-3) cm(2) V(-1) s(-1)) of trial OFETs decrease upon elongation of the alkyl chains. This finding parallels the results of theoretical simulation. The simulation method for amorphous solids developed in this effort should become a useful tool in studies aimed at designing new OSC materials. PMID:27010327

  18. Improvement in Mobility and Stability of n-Type Organic Field-Effect Transistors with a Hole Transporting Interfacial Layer

    Science.gov (United States)

    Nakayama, Ken-ichi; Ishikawa, Motomi; Yokoyama, Masaaki

    2009-02-01

    Field-effect electron mobility and stability of N,N'-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8H) improved when a hole-transporting layer, used in organic light-emitting diodes, was inserted between the gate insulator and the channel layer. This result suggests that insertion of an electronically active interfacial layer of an organic semiconductor is more effective in eliminating electron traps of the insulator surface compared to conventional surface treatment to obtain an inert surface.

  19. Ambipolar diffusion in low-mass star formation. I. General comparison with the ideal MHD case

    CERN Document Server

    Masson, Jacques; Hennebelle, Patrick; Vaytet, Neil; Commerçon, Benoit

    2015-01-01

    In this paper, we provide a more accurate description of the evolution of the magnetic flux redistribution during prestellar core collapse by including resistive terms in the magnetohydrodynamics (MHD) equations. We focus more particularly on the impact of ambipolar diffusion. We use the adaptive mesh refinement code RAMSES to carry out such calculations. The resistivities required to calculate the ambipolar diffusion terms were computed using a reduced chemical network of charged, neutral and grain species. The inclusion of ambipolar diffusion leads to the formation of a magnetic diffusion barrier in the vicinity of the core, preventing accumulation of magnetic flux in and around the core and amplification of the field above 0.1G. The mass and radius of the first Larson core remain similar between ideal and non-ideal MHD models. This diffusion plateau has crucial consequences on magnetic braking processes, allowing the formation of disk structures. Magnetically supported outflows launched in ideal MHD models...

  20. From Classical to Quantum Transistor

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2009-05-01

    Full Text Available In this article the classical transistor and the basic physics underlying the operation of single electron transistor are presented; a brief history of transistor and current technological issues are discussed.

  1. Self-Assembled Organic Single Crystalline Nanosheet for Solution Processed High-Performance n-Channel Field-Effect Transistors.

    Science.gov (United States)

    Kim, Jin Hong; Park, Sang Kyu; Kim, Jong H; Whang, Dong Ryeol; Yoon, Won Sik; Park, Soo Young

    2016-07-01

    Submillimeter sized n-channel organic single crystalline nanosheet based on dicyanodistyrylbenzene derivative, (2E,2'E)-3,3'-(2,5-dimethoxy-1,4-pheny-lene)bis(2-(5-(4-(trifluoromethyl)phenyl)thiophen-2-yl)acrylonitrile) (Me-4-TFPTA), is developed. Strong π-π interaction, hydrogen bonding interactions derived from cyano group (CN) as well as solvent inclusion along the lateral direction play a key role in forming nanosheet morphology. Me-4-TFPTA nanosheets exhibit excellent field-effect electron mobility of up to 7.81 cm(2) v(-1) s(-1) . PMID:27165653

  2. Improvement in semiconductor laser printing using a sacrificial protecting layer for organic thin-film transistors fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Ludovic, E-mail: rapp@lp3.univ-mrs.fr [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Cibert, Christophe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nenon, Sebastien [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Alloncle, Anne Patricia [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nagel, Matthias [Empa, Swiss Federal Laboratories for Materials Testing and Reasearch, Laboratory for Functional Polymers, Uberlandstrasse 129, 8600 Duebendorf (Switzerland); Lippert, Thomas [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen PSI (Switzerland); Videlot-Ackermann, Christine; Fages, Frederic [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Delaporte, Philippe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France)

    2011-04-01

    Laser-induced forward transfer (LIFT) has been used to deposit pixels of an organic semiconductor, distyryl-quaterthiophenes (DS4T). The dynamics of the process have been investigated by shadowgraphic imaging for the nanosecond (ns) and picosecond (ps) regime on a time-scale from the laser iradiation to 1.5 {mu}s. The morphology of the deposit has been studied for different conditions. Intermediate sacrificial layer of gold or triazene polymer has been used to trap the incident radiation. Its role is to protect the layer to be transferred from direct irradiation and to provide a mechanical impulse strong enough to eject the material.

  3. Ambipolar transport via trapped-electron whistler instability along open magnetic field lines.

    Science.gov (United States)

    Guo, Zehua; Tang, Xian-Zhu

    2012-09-28

    An open field line plasma is bounded by a chamber wall which intercepts the magnetic field. Steady state requires an upstream plasma source balancing the particle loss to the boundary. In cases where the electrons have a long mean free path, ambipolarity in parallel transport critically depends on collisionless detrapping of the electrons via wave-particle interaction. The trapped-electron whistler instability, whose nonlinear saturation produces a spectrum of whistler waves that is responsible for the electron detrapping flux, is shown to be an unusually robust kinetic instability, which is essential to the universality of the ambipolar constraint in plasma transport.

  4. Air-stable n-channel organic field-effect transistors based on N,N‧-bis(4-trifluoromethylbenzyl)perylene-3,4,9,10-tetracarboxylic diimide

    Science.gov (United States)

    Hosoi, Yoshinobu; Tsunami, Daisuke; Ishii, Hisao; Furukawa, Yukio

    2007-02-01

    Air-stable n-channel field-effect transistors based on thin films of the compound, N, N'-bis(4-trifluoromethylbenzyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB), were fabricated, and the effects of surface treatment and substrate temperature at the film deposition on the electron mobility of the transistors were studied. The maximum mobility, 4.1 × 10 -2 cm 2 V -1 s -1 in the saturation region (1.7 × 10 -2 cm 2 V -1 s -1 in the linear region), was obtained in air for the film deposited at 95 °C on the SiO 2 surface modified with hexamethyldisilazane. The high electron affinity of PTCDI-TFB estimated at 4.8 eV by photoelectron yield spectroscopy and UV-Vis absorption spectroscopy, which is ascribable to the trifluoromethylbenzyl groups, is likely to result in the observed stable transistor operation in air.

  5. Electric Characteristics of the Carbon Nanotube Network Transistor with Directly Grown ZnO Nanoparticles.

    Science.gov (United States)

    Kim, Un Jeong; Bae, Gi Yoon; Suh, Dong Ik; Park, Wanjun

    2016-03-01

    We report on the electrical characteristics of field effect transistors fabricated with random networks of single-walled carbon nanotubes with surfaces modified by ZnO nanoparticles. ZnO nanoparticles are directly grown on single-walled carbon nanotubes by atomic layer deposition using diethylzinc (DEZ) and water. Electrical observations show that ZnO nanoparticles act as charge transfer sources that provide electrons to the nanotube channel. The valley position in ambipolar transport of nanotube transistors is negatively shifted for 3V due to the electronic n-typed property of ZnO nanoparticles. However, the Raman resonance remains invariant despite the charge transfer effect produced by ZnO nanoparticles. PMID:27455727

  6. Electric Characteristics of the Carbon Nanotube Network Transistor with Directly Grown ZnO Nanoparticles.

    Science.gov (United States)

    Kim, Un Jeong; Bae, Gi Yoon; Suh, Dong Ik; Park, Wanjun

    2016-03-01

    We report on the electrical characteristics of field effect transistors fabricated with random networks of single-walled carbon nanotubes with surfaces modified by ZnO nanoparticles. ZnO nanoparticles are directly grown on single-walled carbon nanotubes by atomic layer deposition using diethylzinc (DEZ) and water. Electrical observations show that ZnO nanoparticles act as charge transfer sources that provide electrons to the nanotube channel. The valley position in ambipolar transport of nanotube transistors is negatively shifted for 3V due to the electronic n-typed property of ZnO nanoparticles. However, the Raman resonance remains invariant despite the charge transfer effect produced by ZnO nanoparticles.

  7. A novel Tunneling Graphene Nano Ribbon Field Effect Transistor with dual material gate: Numerical studies

    Science.gov (United States)

    Ghoreishi, Seyed Saleh; Saghafi, Kamyar; Yousefi, Reza; Moravvej-farshi, Mohammad Kazem

    2016-09-01

    In this work, we present Dual Material Gate Tunneling Graphene Nano-Ribbon Field Effect Transistors (DMG-T-GNRFET) mainly to suppress the am-bipolar current with assumption that sub-threshold swing which is one of the important characteristics of tunneling transistors must not be degraded. In the proposed structure, dual material gates with different work functions are used. Our investigations are based on numerical simulations which self-consistently solves the 2D Poisson based on an atomistic mode-space approach and Schrodinger equations, within the Non-Equilibrium Green's (NEGF). The proposed device shows lower off-current and on-off ratio becomes 5order of magnitude greater than the conventional device. Also two different short channel effects: Drain Induced Barrier Shortening (DIBS) and hot-electron effect are improved in the proposed device compare to the main structure.

  8. Integrating carbon nanotubes into silicon by means of vertical carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi

    2014-01-01

    Single-walled carbon nanotubes have been integrated into silicon for use in vertical carbon nanotube field-effect transistors (CNTFETs). A unique feature of these devices is that a silicon substrate and a metal contact are used as the source and drain for the vertical transistors, respectively. These CNTFETs show very different characteristics from those fabricated with two metal contacts. Surprisingly, the transfer characteristics of the vertical CNTFETs can be either ambipolar or unipolar (p-type or n-type) depending on the sign of the drain voltage. Furthermore, the p-type/n-type character of the devices is defined by the doping type of the silicon substrate used in the fabrication process. A semiclassical model is used to simulate the performance of these CNTFETs by taking the conductance change of the Si contact under the gate voltage into consideration. The calculation results are consistent with the experimental observations. This journal is © the Partner Organisations 2014.

  9. Field-effect transistor structures on the basis of poly(3-hexylthiophene), fullerene derivatives [60]PCBM, [70]PCBM, and nickel nanoparticles

    Science.gov (United States)

    Aleshin, A. N.; Shcherbakov, I. P.; Trapeznikova, I. N.; Petrov, V. N.

    2016-09-01

    Organic field-effect transistor (OFET) structures with the active layers on the basis of composite films of semiconductor polymer poly(3-hexylthiophene) (P3HT), fullerene derivatives [60]PCBM, [70]PCBM, and nickel (Ni) nanoparticles are obtained, and their optical, electrical, and photoelectrical properties are studied. It is shown that introducing Ni nanoparticles into P3HT: [60]PCBM and P3HT: [70]PCBM films leads to an increase in the absorption and to quenching of photoluminescence of the composite in the 400-600 nm spectral band due to the plasmon effect. In P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFET structures at the P3HT: [60]PCBM and P3HT: [70]PCBM concentrations of ~1: 1 and Ni concentrations of ~3-5 wt %, current-voltage ( I-V) characteristics typical of ambipolar OFETs with the dominant hole conduction are observed. The charge-carrier (hole) mobilities calculated from the I-V characteristic at V G =-10 V were found to be ~0.46 cm2/(V s) for P3HT: [60]PCBM: Ni and ~4.7 cm2/(V s) for P3HT: [70]PCBM: Ni, which means that the mobility increases if [60]PCBM in the composition is replaced with [70]PCBM. The effect of light on the I-V characteristics of P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFETs is studied.

  10. Highly reliable top-gated thin-film transistor memory with semiconducting, tunneling, charge-trapping, and blocking layers all of flexible polymers.

    Science.gov (United States)

    Wang, Wei; Hwang, Sun Kak; Kim, Kang Lib; Lee, Ju Han; Cho, Suk Man; Park, Cheolmin

    2015-05-27

    The core components of a floating-gate organic thin-film transistor nonvolatile memory (OTFT-NVM) include the semiconducting channel layer, tunneling layer, floating-gate layer, and blocking layer, besides three terminal electrodes. In this study, we demonstrated OTFT-NVMs with all four constituent layers made of polymers based on consecutive spin-coating. Ambipolar charges injected and trapped in a polymer electret charge-controlling layer upon gate program and erase field successfully allowed for reliable bistable channel current levels at zero gate voltage. We have observed that the memory performance, in particular the reliability of a device, significantly depends upon the thickness of both blocking and tunneling layers, and with an optimized layer thickness and materials selection, our device exhibits a memory window of 15.4 V, on/off current ratio of 2 × 10(4), read and write endurance cycles over 100, and time-dependent data retention of 10(8) s, even when fabricated on a mechanically flexible plastic substrate.

  11. Pixel structures to compensate nonuniform threshold voltage and mobility of polycrystalline silicon thin-film transistors using subthreshold current for large-size active matrix organic light-emitting diode displays

    Science.gov (United States)

    Na, Jun-Seok; Kwon, Oh-Kyong

    2014-01-01

    We propose pixel structures for large-size and high-resolution active matrix organic light-emitting diode (AMOLED) displays using a polycrystalline silicon (poly-Si) thin-film transistor (TFT) backplane. The proposed pixel structures compensate the variations of the threshold voltage and mobility of the driving TFT using the subthreshold current. The simulated results show that the emission current error of the proposed pixel structure B ranges from -2.25 to 2.02 least significant bit (LSB) when the variations of the threshold voltage and mobility of the driving TFT are ±0.5 V and ±10%, respectively.

  12. Electrical properties of functionalized nanowire field effect transistors

    OpenAIRE

    Weitz, Ralf Thomas

    2008-01-01

    The utilization of functional organic materials holds great promise for applications in electronic devices. Semiconducting organic molecules are frequently used as channel material in field effect transistors, due to the ease by which they can be assembled as such components, and the ease with which their properties can be specifically tailored. An extension of the use of organic materials in field effect transistors with the potential to substantially improve the performance of such devices ...

  13. Investigations on Substrate Temperature-Induced Growth Modes of Organic Semiconductors at Dielectric/semiconductor Interface and Their Correlation with Threshold Voltage Stability in Organic Field-Effect Transistors.

    Science.gov (United States)

    Padma, Narayanan; Maheshwari, Priya; Bhattacharya, Debarati; Tokas, Raj B; Sen, Shashwati; Honda, Yoshihide; Basu, Saibal; Pujari, Pradeep Kumar; Rao, T V Chandrasekhar

    2016-02-10

    Influence of substrate temperature on growth modes of copper phthalocyanine (CuPc) thin films at the dielectric/semiconductor interface in organic field effect transistors (OFETs) is investigated. Atomic force microscopy (AFM) imaging at the interface reveals a change from 'layer+island' to "island" growth mode with increasing substrate temperatures, further confirmed by probing the buried interfaces using X-ray reflectivity (XRR) and positron annihilation spectroscopic (PAS) techniques. PAS depth profiling provides insight into the details of molecular ordering while positron lifetime measurements reveal the difference in packing modes of CuPc molecules at the interface. XRR measurements show systematic increase in interface width and electron density correlating well with the change from layer + island to coalesced huge 3D islands at higher substrate temperatures. Study demonstrates the usefulness of XRR and PAS techniques to study growth modes at buried interfaces and reveals the influence of growth modes of semiconductor at the interface on hole and electron trap concentrations individually, thereby affecting hysteresis and threshold voltage stability. Minimum hole trapping is correlated to near layer by layer formation close to the interface at 100 °C and maximum to the island formation with large voids between the grains at 225 °C.

  14. Subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory for nonvolatile operation

    Science.gov (United States)

    Huh, In; Cheon, Woo Young; Choi, Woo Young

    2016-04-01

    A subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory (SAT RAM) has been proposed and fabricated for low-power nonvolatile memory applications. The proposed SAT RAM cell demonstrates adjustable subthreshold swing (SS) depending on stored information: small SS in the erase state ("1" state) and large SS in the program state ("0" state). Thus, SAT RAM cells can achieve low read voltage (Vread) with a large memory window in addition to the effective suppression of ambipolar behavior. These unique features of the SAT RAM are originated from the locally stored charge, which modulates the tunneling barrier width (Wtun) of the source-to-channel tunneling junction.

  15. N-type ohmic contacts to undoped GaAs/AlGaAs quantum wells using only front-sided processing: application to ambipolar FETs

    Science.gov (United States)

    Taneja, D.; Sfigakis, F.; Croxall, A. F.; Das Gupta, K.; Narayan, V.; Waldie, J.; Farrer, I.; Ritchie, D. A.

    2016-06-01

    We report the development of a simple and reliable, front-sided-only fabrication technique for n-type ohmic contacts to two-dimensional electron gases (2DEGs) in undoped GaAs/AlGaAs quantum wells. We have adapted the well-established recessed ohmic contacts/insulated metal gate technique for inducing a 2DEG in an undoped triangular well to also work reliably for undoped square quantum wells. Our adaptation involves a change in the procedure for etching the ohmic contact pits to optimise the etch side-wall profile and depth. As an application of our technique, we present a front-side-gated ambipolar field effect transistor (FET), where both 2D electron and hole gases can be induced in the same quantum well. We present results of low-temperature (0.3 K - 4 K) transport measurements of this device, including assessment of the n-type ohmic contact quality. On the basis of our findings, we discuss why the fabrication of these contacts is difficult and how our technique circumvents the challenges.

  16. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  17. High Power Switching Transistor

    Science.gov (United States)

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.

    1983-01-01

    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  18. Polyphosphonium-based ion bipolar junction transistors.

    Science.gov (United States)

    Gabrielsson, Erik O; Tybrandt, Klas; Berggren, Magnus

    2014-11-01

    Advancements in the field of electronics during the past few decades have inspired the use of transistors in a diversity of research fields, including biology and medicine. However, signals in living organisms are not only carried by electrons but also through fluxes of ions and biomolecules. Thus, in order to implement the transistor functionality to control biological signals, devices that can modulate currents of ions and biomolecules, i.e., ionic transistors and diodes, are needed. One successful approach for modulation of ionic currents is to use oppositely charged ion-selective membranes to form so called ion bipolar junction transistors (IBJTs). Unfortunately, overall IBJT device performance has been hindered due to the typical low mobility of ions, large geometries of the ion bipolar junction materials, and the possibility of electric field enhanced (EFE) water dissociation in the junction. Here, we introduce a novel polyphosphonium-based anion-selective material into npn-type IBJTs. The new material does not show EFE water dissociation and therefore allows for a reduction of junction length down to 2 μm, which significantly improves the switching performance of the ion transistor to 2 s. The presented improvement in speed as well the simplified design will be useful for future development of advanced iontronic circuits employing IBJTs, for example, addressable drug-delivery devices. PMID:25553192

  19. 有机静电感应三级管动作特性的实验分析%Experimental analysis of operating characteristics of organic semiconductor static induction transistor

    Institute of Scientific and Technical Information of China (English)

    薛严冰; 王东兴

    2006-01-01

    The organic static induction transistor (OSIT) fabricated with organic semiconductor material copper-phthalocyanine(CuPc)is discussed in the paper. It has Schottky Gate electrode and sandwich structure of Au/CuPc/Al/CuPc/Au/glass. The operation mechanism of the device is studied on the physical model with practical parameters. Potential distribution and field intensity distribution in the conduction channel are computed by using finite-element method. By processing static experimental data with some mathematic tools,the V- I expression of CuPc/Al Schottky Gate is obtained and it is verified that OSIT has insaturation current property along with the increase of Drain bias voltage. By using AC small signal circuit model and appropriate numerical simulation method, the dynamic operating characteristics are investigated, and some influenced factors are analyzed.

  20. The effect of ambipolar electric fields on the electron heating in capacitive RF plasmas

    CERN Document Server

    Schulze, J; Derzsi, A; Korolov, I; Schuengel, E

    2016-01-01

    We investigate the electron heating dynamics in electropositive argon and helium capacitively coupled RF discharges driven at 13.56 MHz by Particle in Cell simulations and by an analytical model. The model allows to calculate the electric field outside the electrode sheaths, space and time resolved within the RF period. Electrons are found to be heated by strong ambipolar electric fields outside the sheath during the phase of sheath expansion in addition to classical sheath expansion heating. By tracing individual electrons we also show that ionization is primarily caused by electrons that collide with the expanding sheath edge multiple times during one phase of sheath expansion due to backscattering towards the sheath by collisions. A synergistic combination of these different heating events during one phase of sheath expansion is required to accelerate an electron to energies above the threshold for ionization. The ambipolar electric field outside the sheath is found to be time modulated due to a time modul...

  1. Global simulations of protoplanetary disks with ohmic resistivity and ambipolar diffusion

    CERN Document Server

    Gressel, Oliver; Nelson, Richard P; McNally, Colin P

    2015-01-01

    Protoplanetary disks are believed to accrete onto their central T Tauri star because of magnetic stresses. Recently published shearing box simulations indicate that Ohmic resistivity, ambipolar diffusion and the Hall effect all play important roles in disk evolution. In the presence of a vertical magnetic field, the disk remains laminar between 1-5au, and a magnetocentrifugal disk wind forms that provides an important mechanism for removing angular momentum. Questions remain, however, about the establishment of a true physical wind solution in the shearing box simulations because of the symmetries inherent in the local approximation. We present global MHD simulations of protoplanetary disks that include Ohmic resistivity and ambipolar diffusion, where the time-dependent gas-phase electron and ion fractions are computed under FUV and X-ray ionization with a simplified recombination chemistry. Our results show that the disk remains laminar, and that a physical wind solution arises naturally in global disk model...

  2. Ambipolar potential measurement plans and instrumentation. Final report, 1 October 1980-30 September 1982

    International Nuclear Information System (INIS)

    A Thomson parabola charged particle spectrometer was built with an energy resolution of 80 keV and an active silicon detector array that is read by a computer-compatible CAMAC. The instrument was checked out at the University of Rochester Omega Laser facility. Experiments to measure the ambipolar potential and the dE/dx thermonuclear target to within 50 keV are now possible. The ion temperature of the burn can be determined to within 10%

  3. On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

    Directory of Open Access Journals (Sweden)

    C. M. Hall

    Full Text Available By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.

    Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence

  4. Control of residual carbon concentration in GaN high electron mobility transistor and realization of high-resistance GaN grown by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    He, X.G. [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Zhao, D.G., E-mail: dgzhao@red.semi.ac.cn [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Jiang, D.S.; Liu, Z.S.; Chen, P.; Le, L.C.; Yang, J.; Li, X.J. [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Zhang, S.M.; Zhu, J.J.; Wang, H.; Yang, H. [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215125 (China)

    2014-08-01

    GaN films were grown by metal-organic chemical vapor deposition (MOCVD) under various growth conditions. The influences of MOCVD growth parameters, i.e., growth pressure, ammonia (NH{sub 3}) flux, growth temperature, trimethyl-gallium flux and H{sub 2} flux, on residual carbon concentration ([C]) were systematically investigated. Secondary ion mass spectroscopy measurements show that [C] can be effectively modulated by growth conditions. Especially, it can increase by reducing growth pressure up to two orders of magnitude. High-resistance (HR) GaN epilayer with a resistivity over 1.0 × 10{sup 9} Ω·cm is achieved by reducing growth pressure. The mechanism of the formation of HR GaN epilayer is discussed. An Al{sub x}Ga{sub 1−x}N/GaN high electron mobility transistor structure with a HR GaN buffer layer and an additional low-carbon GaN channel layer is presented, exhibiting a high two dimensional electron gas mobility of 1815 cm{sup 2}/Vs. - Highlights: • Influence of MOCVD parameters on residual carbon concentration in GaN is studied. • GaN layer with a resistivity over 1 × 10{sup 9} Ω·cm is achieved by reducing growth pressure. • High electron mobility transistor (HEMT) structures were prepared. • Control of residual carbon content results in HEMT with high 2-D electron gas mobility.

  5. Density functional theory study on organic semiconductor for field effect transistors: Symmetrical and unsymmetrical porphyrazine derivatives with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene moieties

    Institute of Scientific and Technical Information of China (English)

    CAI Xue; ZHANG YueXing; QI DongDong; JIANG JianZhuang

    2009-01-01

    Density functional theory (DFT) calculations were carried out to investigate the organic field effect transistor (OFET) performance of the symmetrical metal-free tetrakis (1,2,5-thiadiazole) porphyrazine (S4)PzH2 and tetrakis (1,4-diamyloxybenzene) (A4)PzH2 as well as the low-symmetry metal-free porphy-razine with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene groups in the ratio 2:2 (cis) and 1:3, that is, (cis-S2A2)PzH2 and (SA3)PzH2, (S = 1,2,5-thiadiazole ring, A .-. annulated 1,4-diamyloxy-benzene ring, Pz= porphyrazine) in terms of the highest occupied molecular orbital (HOMO) and lowest unoc-cupied molecular orbital (LUMO) energy, ionization energy (IE), electron affinity (EA), and their reor-ganization energy (λ) during the charge-transport process. On the basis of Marcus electron transfer theory, electronic couplings (V) and field effect transistor (FET) properties for the four compounds with known crystal structure have been calculated. The electron transfer mobility (μ_) is revealed to be 0.056 (cis-S2A2)PzH2, (SA3)PzH2, and (A4)PzH2, respectively. The present work represents the theoretical effort towards understanding the OFET properties of symmetrical and unsymmetrical porphyrazine deriva-tives with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene.

  6. Experimental study of the hysteresis in hydrogenated amorphous silicon thin-film transistors for an active matrix organic light-emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Hoon; Shin, Kwang-Sub; Park, Joong-Hyun; Han, Min-Koo [Seoul National University, Seoul (Korea, Republic of)

    2006-01-15

    An experimental scheme for validating the cause of the hysteresis phenomenon in hydrogenated amorphous-silicon-thin-film transistors (a-Si:H TFTs) is reported. A different gate starting voltage to the desired gate voltage has been considered to prove an effect of filling an acceptor-like or donor-like state in the interface. The integration time of the semiconductor parameter analyzer has also been controlled to investigate the effect between the de-trapping rate and hysteresis. The experimental results show that the previous data voltage in the (n-1)th frame affects the OLED current in the (n)th frame.

  7. Impact of regioregularity on thin-film transistor and photovoltaic cell performances of pentacene-containing polymers

    KAUST Repository

    Jiang, Ying

    2012-01-01

    Regioregular pentacene-containing polymers were synthesized with alkylated bithiophene (BT) and cyclopentadithiophene (CPDT) as comonomers. Among them, 2,9-conjugated polymers PnBT-2,9 and PnCPDT-2,9 achieved the best performance in transistor and photovoltaic devices respectively. The former achieved the most highly ordered structures in thin films, yielding ambipolar transistor behavior with hole and electron mobilities up to 0.03 and 0.02 cm 2 V -1 s -1 on octadecylsilane-treated substrates. The latter achieved photovoltaic power conversion efficiencies up to 0.33%. The impact of regioregularity and direction of conjugation-extension (2,9 vs. 2,10), on thin-film order and device performance has been demonstrated for the pentacene-containing polymers for the first time, providing insight towards future functional material design. © 2012 The Royal Society of Chemistry.

  8. Diode, transistor & fet circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Diode, Transistor and FET Circuits Manual is a handbook of circuits based on discrete semiconductor components such as diodes, transistors, and FETS. The book also includes diagrams and practical circuits. The book describes basic and special diode characteristics, heat wave-rectifier circuits, transformers, filter capacitors, and rectifier ratings. The text also presents practical applications of associated devices, for example, zeners, varicaps, photodiodes, or LEDs, as well as it describes bipolar transistor characteristics. The transistor can be used in three basic amplifier configuration

  9. Low-Programmable-Voltage Nonvolatile Memory Devices Based on Omega-shaped Gate Organic Ferroelectric P(VDF-TrFE) Field Effect Transistors Using p-type Silicon Nanowire Channels

    Institute of Scientific and Technical Information of China (English)

    Ngoc Huynh Van; Jae-Hyun Lee; Dongmok Whang; Dae Joon Kang

    2015-01-01

    A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped gate organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)). We overcame the interfacial layer problem by incorporating P(VDF-TrFE) as a ferroelectric gate using a low-temperature fabrication process. Our memory devices exhibited excellent memory characteristics with a low programming voltage of ±5 V, a large modulation in channel conductance between ON and OFF states exceeding 105, a long retention time greater than 3 9 104 s, and a high endurance of over 105 programming cycles while maintaining an ION/IOFF ratio higher than 102.

  10. Quantum thermal transistor

    CERN Document Server

    Joulain, Karl; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-01-01

    We demonstrate that a thermal transistor can be made up with a quantum system of 3 interacting subsystems , coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved determining the heat fluxes by means of the strong-coupling formalism. For the case of 3 interacting spins, in which one of them is coupled to the other 2, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nano systems.

  11. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir...

  12. Low-Temperature Band Transport and Impact of Contact Resistance in Organic Field-Effect Transistors Based on Single-Crystal Films of Ph-BTBT-C10

    Science.gov (United States)

    Cho, Joung-min; Mori, Takehiko

    2016-06-01

    Transistors based on single-crystal films of 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) fabricated using the blade-coating method are investigated by the four-probe method down to low temperatures. The four-probe mobility is as large as 18 cm2/V s at room temperature, and increases to 45 cm2/V s at 80 K. At 60 K the two-probe mobility drops abruptly by about 50%, but the mobility drop is mostly attributed to the increase of the source resistance. The carrier transport in the present single-crystal film is regarded as essentially bandlike down to 30 K.

  13. Accelerating the life of transistors

    Institute of Scientific and Technical Information of China (English)

    Qi Haochun; Lü Changzhi; Zhang Xiaoling; Xie Xuesong

    2013-01-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object,the test of accelerating life is conducted in constant temperature and humidity,and then the data are statistically analyzed with software developed by ourselves.According to degradations of such sensitive parameters as the reverse leakage current of transistors,the lifetime order of transistors is about more than 104 at 100 ℃ and 100% relative humidity (RH) conditions.By corrosion fracture of transistor outer leads and other failure modes,with the failure truncated testing,the average lifetime rank of transistors in different distributions is extrapolated about 103.Failure mechanism analyses of degradation of electrical parameters,outer lead fracture and other reasons that affect transistor lifetime are conducted.The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

  14. Accelerating the life of transistors

    Science.gov (United States)

    Haochun, Qi; Changzhi, Lü; Xiaoling, Zhang; Xuesong, Xie

    2013-06-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object, the test of accelerating life is conducted in constant temperature and humidity, and then the data are statistically analyzed with software developed by ourselves. According to degradations of such sensitive parameters as the reverse leakage current of transistors, the lifetime order of transistors is about more than 104 at 100 °C and 100% relative humidity (RH) conditions. By corrosion fracture of transistor outer leads and other failure modes, with the failure truncated testing, the average lifetime rank of transistors in different distributions is extrapolated about 103. Failure mechanism analyses of degradation of electrical parameters, outer lead fracture and other reasons that affect transistor lifetime are conducted. The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

  15. A Matterwave Transistor Oscillator

    CERN Document Server

    Caliga, Seth C; Zozulya, Alex A; Anderson, Dana Z

    2012-01-01

    A triple-well atomtronic transistor combined with forced RF evaporation is used to realize a driven matterwave oscillator circuit. The transistor is implemented using a metalized compound glass and silicon substrate. On-chip and external currents produce a cigar-shaped magnetic trap, which is divided into transistor source, gate, and drain regions by a pair of blue-detuned optical barriers projected onto the magnetic trap through a chip window. A resonant laser beam illuminating the drain portion of the atomtronic transistor couples atoms emitted by the gate to the vacuum. The circuit operates by loading the source with cold atoms and utilizing forced evaporation as a power supply that produces a positive chemical potential in the source, which subsequently drives oscillation. High-resolution in-trap absorption imagery reveals gate atoms that have tunneled from the source and establishes that the circuit emits a nominally mono-energetic matterwave with a frequency of 23.5(1.0) kHz by tunneling from the gate, ...

  16. Spin-torque transistor

    NARCIS (Netherlands)

    Bauer, G.E.W.; Brataas, A.; Tserkovnyak, Y.; Van Wees, B.J.

    2003-01-01

    A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure–drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin

  17. Radiation-hardened transistor and integrated circuit

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Kwok K. (Albuquerque, NM)

    2007-11-20

    A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.

  18. The effect of ambipolar diffusion on low-density molecular ISM filaments

    Science.gov (United States)

    Ntormousi, Evangelia; Hennebelle, Patrick; André, Philippe; Masson, Jacques

    2016-05-01

    Context. The filamentary structure of the molecular interstellar medium and the potential link of this morphology to star formation have been brought into focus recently by high resolution observational surveys. An especially puzzling matter is that local interstellar filaments appear to have the same thickness, independent of their column density. This requires a theoretical understanding of their formation process and the physics that governs their evolution. Aims: In this work we explore a scenario in which filaments are dissipative structures of the large-scale interstellar turbulence cascade and ion-neutral friction (also called ambipolar diffusion) is affecting their sizes by preventing small-scale compressions. Methods: We employ high-resolution (5123 and 10243), 3D magnetohydrodynamic (MHD) simulations, performed with the grid code RAMSES, to investigate non-ideal MHD turbulence as a filament formation mechanism. We focus the analysis on the mass and thickness distributions of the resulting filamentary structures. Results: Simulations of both driven and decaying MHD turbulence show that the morphologies of the density and the magnetic field are different when ambipolar diffusion is included in the models. In particular, the densest structures are broader and more massive as an effect of ion-neutral friction and the power spectra of both the velocity and the density steepen at a smaller wavenumber. Conclusions: The comparison between ideal and non-ideal MHD simulations shows that ambipolar diffusion causes a shift of the filament thickness distribution towards higher values. However, none of the distributions exhibit the pronounced peak found in the observed local filaments. Limitations in dynamical range and the absence of self-gravity in these numerical experiments do not allow us to conclude at this time whether this is due to the different filament selection or due to the physics inherent of the filament formation.

  19. Density functional theory study on organic semiconductor for field effect transistors: Symmetrical and unsymmetrical porphyrazine derivatives with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene moieties

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Density functional theory (DFT) calculations were carried out to investigate the organic field effect transistor (OFET) performance of the symmetrical metal-free tetrakis (1,2,5-thiadiazole) porphyrazine (S4)PzH2 and tetrakis (1,4-diamyloxybenzene) (A4)PzH2 as well as the low-symmetry metal-free porphy- razine with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene groups in the ratio 2:2 (cis) and 1:3, that is, (cis-S2A2)PzH2 and (SA3)PzH2, (S = 1,2,5-thiadiazole ring, A = annulated 1,4-diamyloxy-benzene ring, Pz = porphyrazine) in terms of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy, ionization energy (IE), electron affinity (EA), and their reorganization energy (λ) during the charge-transport process. On the basis of Marcus electron transfer theory, electronic couplings (V) and field effect transistor (FET) properties for the four compounds with known crystal structure have been calculated. The electron transfer mobility (μ -) is revealed to be 0.056 cm2·V-1·s-1 for (S4)PzH2. The hole transfer mobility (μ+) is 0.075, 0.098, and 8.20 cm2·V-1·s-1 for (cis-S2A2)PzH2, (SA3)PzH2, and (A4)PzH2, respectively. The present work represents the theoretical effort towards understanding the OFET properties of symmetrical and unsymmetrical porphyrazine derivatives with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene.

  20. A Selenophene-Based Low-Bandgap Donor-Acceptor Polymer Leading to Fast Ambipolar Logic

    KAUST Repository

    Kronemeijer, Auke J.

    2012-02-20

    Fast ambipolar CMOS-like logic is demonstrated using a new selenophene-based donor-acceptor polymer semiconductor. The polymer exhibits saturation hole and electron mobilities of 0.46 cm 2/Vs and 0.84 cm 2/Vs. Inverters are fabricated with high gains while three-stage ring oscillators show stable oscillation with an unprecedented maximum frequency of 182 kHz at a relatively low supply voltage of 50 V. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A simple drain current model for Schottky-barrier carbon nanotube field effect transistors

    International Nuclear Information System (INIS)

    We report on a new computational model to efficiently simulate carbon nanotube-based field effect transistors (CNT-FET). In the model, a central region is formed by a semiconducting nanotube that acts as the conducting channel, surrounded by a thin oxide layer and a metal gate electrode. At both ends of the semiconducting channel, two semi-infinite metallic reservoirs act as source and drain contacts. The current-voltage characteristics are computed using the Landauer formalism, including the effect of the Schottky barrier physics. The main operational regimes of the CNT-FET are described, including thermionic and tunnel current components, capturing ambipolar conduction, multichannel ballistic transport and electrostatics dominated by the nanotube capacitance. The calculations are successfully compared to results given by more sophisticated methods based on non-equilibrium Green's function formalism (NEGF)

  2. Improved Tunnel-FET inverter performance with SiGe/Si heterostructure nanowire TFETs by reduction of ambipolarity

    Science.gov (United States)

    Richter, S.; Trellenkamp, S.; Schäfer, A.; Hartmann, J. M.; Bourdelle, K. K.; Zhao, Q. T.; Mantl, S.

    2015-06-01

    Complementary MOSFET and Tunnel-FET inverters based on tri-gated strained Si nanowire arrays are demonstrated. The voltage transfer characteristics as well as the inverter supply currents of both inverter types are analyzed and compared. A degradation of the inverter output voltage is observed due to the ambipolar transfer characteristics of the symmetric homostructure TFET devices. Emulated TFET inverters based on the measured transfer characteristics of SiGe/Si heterostructure nanowire array n-channel TFETs with reduced ambipolarity demonstrate improved inverter switching for supply voltages down to VDD = 0.2 V.

  3. Molecular host-guest energy-transfer system with an ultralow amplified spontaneous emission threshold employing an ambipolar semiconducting host matrix.

    Science.gov (United States)

    Toffanin, Stefano; Capelli, Raffaella; Hwu, Tsyr-Yuan; Wong, Ken-Tsung; Plötzing, Tobias; Först, Michael; Muccini, Michele

    2010-01-14

    We report on the characteristics of a host-guest lasing system obtained by coevaporation of an oligo(9,9-diarylfluorene) derivative named T3 with the red-emitter 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye (DCM). We demonstrate that the ambipolar semiconductor T3 can be implemented as an active matrix in the realization of a host-guest system in which an efficient energy transfer takes place from the T3 matrix to the lasing DCM molecules. We performed a detailed spectroscopic study on the system by systematically varying the DCM concentration in the T3 matrix. Measurements of steady-state photoluminescence (PL), PL quantum yield (PLQY), time-resolved picosecond PL, and amplified spontaneous emission (ASE) threshold are used to optimize the acceptor concentration at which the ASE from DCM molecules takes place with the lowest threshold. The sample with a DCM relative deposition ratio of 2% shows an ASE threshold as low as 0.6 kW/cm(2) and a net optical gain measured by femtosecond time-resolved pump-and-probe spectroscopy as high as 77 cm(-1). The reference model system Alq(3):DCM sample measured in exactly the same experimental conditions presents an one-order-of-magnitude higher ASE threshold. The ASE threshold of T3:DCM is the lowest reported to date for a molecular host-guest energy-transfer system, which makes the investigated blend an appealing system for use as an active layer in lasing devices. In particular, the ambipolar charge transport properties of the T3 matrix and its field-effect characteristics make the host-guest system presented here an ideal candidate for the realization of electrically pumped organic lasers.

  4. Ambipolar Electric Field, Photoelectrons, and Their Role in Atmospheric Escape From Hot Jupiters

    Science.gov (United States)

    Cohen, O.; Glocer, A.

    2012-01-01

    Atmospheric mass loss from Hot Jupiters can be large due to the close proximity of these planets to their host star and the strong radiation the planetary atmosphere receives. On Earth, a major contribution to the acceleration of atmospheric ions comes from the vertical separation of ions and electrons, and the generation of the ambipolar electric field. This process, known as the "polar wind," is responsible for the transport of ionospheric constituents to Earth's magnetosphere, where they are well observed. The polar wind can also be enhanced by a relatively small fraction of super-thermal electrons (photoelectrons) generated by photoionization.We formulate a simplified calculation of the effect of the ambipolar electric field and the photoelectrons on the ion scale height in a generalized manner. We find that the ion scale height can be increased by a factor of 2-15 due to the polar wind effects. We also estimate a lower limit of an order of magnitude increase of the ion density and the atmospheric mass-loss rate when polar wind effects are included.

  5. Silicene field-effect transistors operating at room temperature

    Science.gov (United States)

    Tao, Li; Cinquanta, Eugenio; Chiappe, Daniele; Grazianetti, Carlo; Fanciulli, Marco; Dubey, Madan; Molle, Alessandro; Akinwande, Deji

    2015-03-01

    Free-standing silicene, a silicon analogue of graphene, has a buckled honeycomb lattice and, because of its Dirac bandstructure combined with its sensitive surface, offers the potential for a widely tunable two-dimensional monolayer, where external fields and interface interactions can be exploited to influence fundamental properties such as bandgap and band character for future nanoelectronic devices. The quantum spin Hall effect, chiral superconductivity, giant magnetoresistance and various exotic field-dependent states have been predicted in monolayer silicene. Despite recent progress regarding the epitaxial synthesis of silicene and investigation of its electronic properties, to date there has been no report of experimental silicene devices because of its air stability issue. Here, we report a silicene field-effect transistor, corroborating theoretical expectations regarding its ambipolar Dirac charge transport, with a measured room-temperature mobility of ˜100 cm2 V-1 s-1 attributed to acoustic phonon-limited transport and grain boundary scattering. These results are enabled by a growth-transfer-fabrication process that we have devised—silicene encapsulated delamination with native electrodes. This approach addresses a major challenge for material preservation of silicene during transfer and device fabrication and is applicable to other air-sensitive two-dimensional materials such as germanene and phosphorene. Silicene's allotropic affinity with bulk silicon and its low-temperature synthesis compared with graphene or alternative two-dimensional semiconductors suggest a more direct integration with ubiquitous semiconductor technology.

  6. Polarization induced doped transistor

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Huili (Grace); Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  7. Field-effect transistor chemical sensors of single nanoribbon of copper phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Copper phthalocyanine (CuPc) nanoribbon field-effect transistors were implemented as chemical sensors. They showed fast response and high reversibility in the detection of the tetrahydrofuran atmosphere at room temperature. The drain current of the field-effect transistor sensor decreased from 6.7 to 0.2 nA when the transistor was measured under the tetrahydrofuran atmosphere. The sensor was self-refreshable in a few minutes. These results demonstrate that the organic single crystalline nanoribbon transistors could effectively act as chemical sensors.

  8. Fullerene C70 as a p-type donor in organic photovoltaic cells

    International Nuclear Information System (INIS)

    Fullerenes and their derivatives have been widely used as n-type materials in organic transistor and photovoltaic devices. Though it is believed that they shall be ambipolar in nature, there have been few direct experimental proofs for that. In this work, fullerene C70, known as an efficient acceptor, has been employed as a p-type electron donor in conjunction with 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile as an electron acceptor in planar-heterojunction (PHJ) organic photovoltaic (OPV) cells. High fill factors (FFs) of more than 0.70 were reliably achieved with the C70 layer even up to 100 nm thick in PHJ cells, suggesting the superior potential of fullerene C70 as the p-type donor in comparison to other conventional donor materials. The optimal efficiency of these unconventional PHJ cells was 2.83% with a short-circuit current of 5.33 mA/cm2, an open circuit voltage of 0.72 V, and a FF of 0.74. The results in this work unveil the potential of fullerene materials as donors in OPV devices, and provide alternative approaches towards future OPV applications.

  9. Diindeno-fusion of an anthracene as a design strategy for stable organic biradicals

    Science.gov (United States)

    Rudebusch, Gabriel E.; Zafra, José L.; Jorner, Kjell; Fukuda, Kotaro; Marshall, Jonathan L.; Arrechea-Marcos, Iratxe; Espejo, Guzmán L.; Ponce Ortiz, Rocío; Gómez-García, Carlos J.; Zakharov, Lev N.; Nakano, Masayoshi; Ottosson, Henrik; Casado, Juan; Haley, Michael M.

    2016-08-01

    The consequence of unpaired electrons in organic molecules has fascinated and confounded chemists for over a century. The study of open-shell molecules has been rekindled in recent years as new synthetic methods, improved spectroscopic techniques and powerful computational tools have been brought to bear on this field. Nonetheless, it is the intrinsic instability of the biradical species that limits the practicality of this research. Here we report the synthesis and characterization of a molecule based on the diindeno[b,i]anthracene framework that exhibits pronounced open-shell character yet possesses remarkable stability. The synthetic route is rapid, efficient and possible on the gram scale. The molecular structure was confirmed through single-crystal X-ray diffraction. From variable-temperature Raman spectroscopy and magnetic susceptibility measurements a thermally accessible triplet excited state was found. Organic field-effect transistor device data show an ambipolar performance with balanced electron and hole mobilities. Our results demonstrate the rational design and synthesis of an air- and temperature-stable biradical compound.

  10. Effect of AlN growth temperature on trap densities of in-situ metal-organic chemical vapor deposition grown AlN/AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistors

    Directory of Open Access Journals (Sweden)

    Joseph J. Freedsman

    2012-06-01

    Full Text Available The trapping properties of in-situ metal-organic chemical vapor deposition (MOCVD grown AlN/AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistors (MIS-HFETs with AlN layers grown at 600 and 700 °C has been quantitatively analyzed by frequency dependent parallel conductance technique. Both the devices exhibited two kinds of traps densities, due to AlN (DT-AlN and AlGaN layers (DT-AlGaN respectively. The MIS-HFET grown at 600 °C showed a minimum DT-AlN and DT-AlGaN of 1.1 x 1011 and 1.2 x 1010 cm-2eV-1 at energy levels (ET -0.47 and -0.36 eV. Further, the gate-lag measurements on these devices revealed less degradation ∼ ≤ 5% in drain current density (Ids-max. Meanwhile, MIS-HFET grown at 700 °C had more degradation in Ids-max ∼26 %, due to high DT-AlN and DT-AlGaN of 3.4 x 1012 and 5 x 1011 cm-2eV-1 positioned around similar ET. The results shows MIS-HFET grown at 600 °C had better device characteristics with trap densities one order of magnitude lower than MIS-HFET grown at 700 °C.

  11. Solution-processed high-LUMO-level polymers in n-type organic field-effect transistors: a comparative study as a semiconducting layer, dielectric layer, or charge injection layer

    International Nuclear Information System (INIS)

    In solution-processed organic field-effect transistors (OFETs), the polymers with high level of lowest unoccupied molecular orbitals (LUMOs, > −3.5 eV) are especially susceptible to electron-trapping that causes low electron mobility and strong instability in successive operation. However, the role of high-LUMO-level polymers could be different depending on their locations relative to the semiconductor/insulator interface, or could even possibly benefit the device in some cases. We constructed unconventional polymer heterojunction n-type OFETs to control the location of the same polymer with a high LUMO level, to be in, under, or above the accumulation channel. We found that although the devices with the polymer in the channel suffer from dramatic instability, the same polymer causes much less instability when it acts as a dielectric modification layer or charge injection layer. Especially, it may even improve the device performance in the latter case. This result helps to improve our understanding of the electron-trapping and explore the value of these polymers in OFETs. (invited article)

  12. Pixel-Level Digital-to-Analog Conversion Scheme with Compensation of Thin-Film-Transistor Variations for Compact Integrated Data Drivers of Active Matrix Organic Light Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Park, Sang-Gyu; Choi, Byong-Deok

    2011-03-01

    The previous pixel-level digital-to-analog-conversion (DAC) scheme that implements a part of a DAC in a pixel circuit turned out to be very efficient for reducing the peripheral area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). However, how the pixel-level DAC can be compatible with the existing pixel circuits including compensation schemes of TFT variations and IR drops on supply rails, which is of primary importance for active matrix organic light emitting diodes (AMOLEDs) is an issue in this scheme, because LTPS TFTs suffer from random variations in their characteristics. In this paper, we show that the pixel-level DAC scheme can be successfully used with the previous compensation schemes by giving two examples of voltage- and current-programming pixels. The previous pixel-level DAC schemes require additional two TFTs and one capacitor, but for these newly proposed pixel circuits, the overhead is no more than two TFTs by utilizing the already existing capacitor. In addition, through a detailed analysis, it has been shown that the pixel-level DAC can be expanded to a 4-bit resolution, or be applied together with 1:2 demultiplexing driving for 6- to 8-in. diagonal XGA AMOLED display panels.

  13. Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors

    Science.gov (United States)

    Tae-Wook Kim,; Byong-Deok Choi,

    2010-03-01

    This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 μm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.

  14. 4.0-inch Active-Matrix Organic Light-Emitting Diode Display Integrated with Driver Circuits Using Amorphous In-Ga-Zn-Oxide Thin-Film Transistors with Suppressed Variation

    Science.gov (United States)

    Ohara, Hiroki; Sasaki, Toshinari; Noda, Kousei; Ito, Shunichi; Sasaki, Miyuki; Endo, Yuta; Yoshitomi, Shuhei; Sakata, Junichiro; Serikawa, Tadashi; Yamazaki, Shunpei

    2010-03-01

    We have newly developed a 4.0-in. quarter video graphics array (QVGA) active-matrix organic light-emitting diode (AMOLED) display integrated with gate and source driver circuits using amorphous In-Ga-Zn-oxide (IGZO) thin-film transistors (TFTs). Focusing on a passivation layer in an inverted staggered bottom gate structure, the threshold voltage of the TFTs can be controlled to have “normally-off” characteristics with suppressed variation by using a SiOx layer formed by sputtering with a low hydrogen content. In addition, small subthreshold swing S/S of 0.19 V/decade, high field-effect mobility µFE of 11.5 cm2 V-1 s-1, and threshold voltage Vth of 1.27 V are achieved. The deposition conditions of the passivation layer and other processes are optimized, and variation in TFT characteristics is suppressed, whereby high-speed operation in gate and source driver circuits can be achieved. Using these driver circuits, the 4.0-in. QVGA AMOLED display integrated with driver circuits can be realized.

  15. Band Alignment for Ambipolar-Doping of SnxZn1-x Te Alloys

    Institute of Scientific and Technical Information of China (English)

    袁小娟; 刘建哲; 宁锋; 张勇; 唐黎明

    2012-01-01

    Using the first-principles band-structure method and a special quasirandom structure(SQS) approach,we have systematically calculated the alloy bowing coefficients and the nature band offsets of SnxZn1-x Te alloys.We show that the bowing coefficients and band gaps of these alloys are sensitively composition dependent.Due to wave functions full overlapping and delocalization of the Sn outermost p orbits and Zn s orbits,the coupling between these states is very strong,resulting in a significant downshift of conduction band edge with the increase of the Sn concentration x,While the valence band edge keeps almost unchanged compared with that of the binary ZnTe,thus improving the possibility for ambipolar-doping.

  16. The effects of contacts and ambipolar electrical transport in nitrogen doped multiwall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W J; Zhang, J Y; Li, P J; Shen, X; Zhang, Q F; Wu, J L [Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871 (China)], E-mail: jlwu@pku.edu.cn

    2008-02-27

    The electrical transport properties of pristine single wall carbon nanotubes (SWCNTs) and lower nitrogen content doped multiwall carbon nanotubes (MWCNTs) (lower than in the experiments of Xiao et al (2005 J. Am. Chem. Soc. 127 8614)) in contact with Au and Pt were studied. Compared with pristine SWCNTs, the Fermi level of the lower nitrogen content doped MWCNTs also moved to the valence band edge with the contact metal's work function increasing. In contrast to Derycke et al' s results (2002 Appl. Phys. Lett. 80 2773), the lower nitrogen content doped MWCNTs exhibited ambipolar behavior, and increasing the doping level led to a reduction of the Schottky barrier height of electrons. Consistent with theoretical calculations, the results support the opinion that the degree of Fermi level pinning is minor for doped carbon nanotubes.

  17. Ambipolar ballistic electron emission microscopy studies of gate-field modified Schottky barriers

    Science.gov (United States)

    Che, Y. L.; Pelz, J. P.

    2010-06-01

    Four-terminal ambipolar ballistic electron emission microscopy studies are conducted on Au/Si and Cu/Si Schottky contacts fabricated on back-gated silicon-on-insulator wafers, allowing the electric field to be varied so that both electron (n)- and hole (p)-Schottky barrier heights can be measured at the same sample location. While the individual n- and p-Schottky barrier heights varied by more than 200 meV between the Au/Si and Cu/Si contacts, for a given sample they sum to within 15 meV of the same value, indicating that the individual variations are due to variations in a local surface dipole as compared with tip effects or variations in local composition.

  18. The effect of ambipolar diffusion on low-density molecular ISM filaments

    CERN Document Server

    Ntormousi, Evangelia; André, Philippe; Masson, Jacques

    2016-01-01

    The filamentary structure of the molecular interstellar medium and the potential link of this morphology to star formation have been brought into focus recently by high resolution observational surveys. An especially puzzling matter is that local interstellar filaments appear to have the same thickness, independent of their column density. This requires a theoretical understanding of their formation process and the physics that governs their evolution. In this work we explore a scenario in which filaments are dissipative structures of the large-scale interstellar turbulence cascade and ion-neutral friction (also called ambipolar diffusion) is affecting their sizes by preventing small-scale compressions. We employ high-resolution, 3D MHD simulations, performed with the grid code RAMSES, to investigate non-ideal MHD turbulence as a filament formation mechanism. We focus the analysis on the mass and thickness distributions of the resulting filamentary structures. Simulations of both driven and decaying MHD turbu...

  19. Leaving of primordial Li$^+$ behind forming structures caused by nanogauss magnetic field through an ambipolar diffusion

    CERN Document Server

    Kusakabe, Motohiko

    2014-01-01

    During the structure formation responsible for the Galaxy, charged and neutral chemical species may have separated at the gravitational contraction in primordial magnetic field (PMF). A gradient in the PMF in a direction perpendicular to the field direction leads to the Lorentz force on the charged species. Resultantly, an ambipolar diffusion occurs, and charged species can move differently from neutral species, which collapses gravitationally during the structure formation. We calculate fluid motions of charged and neutral species assuming a gravitational contraction of neutral matter in a spherically symmetric structure. It is shown that the charged fluid, i.e., proton, electron and $^7$Li$^+$, can significantly decouple from the neutral fluid depending on the field amplitude. The charged species can, therefore, escape from the gravitational collapse with neutral species. A narrow parameter region for an effective chemical separation is identified taking the structure mass, the epoch of the gravitational co...

  20. Three-dimensional simulations of molecular cloud fragmentation regulated by magnetic fields and ambipolar diffusion

    CERN Document Server

    Kudoh, Takahiro; Ogata, Youichi; Yabe, Takashi

    2007-01-01

    We employ the first fully three-dimensional simulation to study the role of magnetic fields and ion-neutral friction in regulating gravitationally-driven fragmentation of molecular clouds. The cores in an initially subcritical cloud develop gradually over an ambipolar diffusion time while the cores in an initially supercritical cloud develop in a dynamical time. The infall speeds on to cores are subsonic in the case of an initially subcritical cloud, while an extended (\\ga 0.1 pc) region of supersonic infall exists in the case of an initially supercritical cloud. These results are consistent with previous two-dimensional simulations. We also found that a snapshot of the relation between density (rho) and the strength of the magnetic field (B) at different spatial points of the cloud coincides with the evolutionary track of an individual core. When the density becomes large, both relations tend to B \\propto \\rho^{0.5}.