Browsing by Author "Ho, Jia-Chong"

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Analysis of pentacene thin film transistors in different atmospheres
(2005)
Wang, Yu-Wu
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Cheng, Horng-Long
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Wang, Yi-Kai
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Hu, Tang-Hsiang
;
Ho, Jia-Chong
This investigation addresses the electrical properties of pentacene-based thin film transistors in air, dry air and high vacuum. A potential barrier model was applied to explain the gate dependent field effect mobility behavior. The results show the trap density in air higher than that in a vacuum.
Bottom-Contact n-Channel Organic Thin-Film Transistors with Naphthalene-Based Derivatives
(2009)
Kao, Chia-Chun
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Lin, Pang
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Chan, Li-Hsin
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Lee, Cheng-Chung
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Ho, Jia-Chong
We investigated bottom-contact organic thin-film transistors based on n-benzyl naphthalene 1,4,5,8-tetracarboxylic diimides. The electrical characteristics were tested in both air and vacuum environments. n-Type semiconductors which are modified by fluorinated imide can be operated in ambient environment. The close packing of the fluorinated ester imide group leads to carrier mobility as high as 1.6x10(-2) cm(2) V(-1) s(-1). The short distance between each molecule can be found via a single-crystal structure.
High-performance bottom-contact devices based on an air-stable n-type organic semiconductor N,N-bis (4-trifluoromethoxybenzyl)-1,4,5,8-naphthalene-tetracarboxylic di-imide
(2007-05-21)
Kao, Chia-Chun
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Lin, Pang
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Lee, Cheng-Chung
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Wang, Yi-Kai
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Ho, Jia-Chong
N,N-bis(4-trifluoromethoxybenzyl)-1,4,5,8-naphthalene-tetracarboxylic di-imide was applied to organic semiconductors for bottom-contact thin-film transistors. The carrier mobility was 1.6x10(-2) cm(2) V-1 s(-1), the threshold voltage (V-T) was +5.5 V, and the on/off current ratio was 8.6x10(5). Devices without any further surface treatments were tested in an ambient environment. The threshold voltage shift (Delta V-T) was verified by gate bias stress measurements. A prototype compound, N,N-bis(4-trifluoromethylbenzyl)naphthalene-1,4,5,8-tetracarboxylic di-imide, shows direct correlation to the bottom-contact device with the varied molecular structure. (c) 2007 American Institute of Physics.
Influence of polymer dielectric surface energy on thin-film transistor performance of solution-processed triethylsilylethynyl anthradithiophene (TES-ADT)
(2012-02-01)
Chen, Liang-Hsiang
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Lin, Pang
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Kim, Choongik
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Chen, Ming-Chou
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Huang, Peng-Yi
This study investigates the correlation between surface energy of polymer dielectrics and the film morphology, microstructure, and thin-film transistor performance of solution-processed 5,11-bis(triethylsilylethynyl) anthradithiophene (TES-ADT) films. The low surface energy polyimide (PI) dielectric induced large grains with strong X-ray reflections for spin-cast TES-ADT films in comparison to high surface energy poly(4-vinyl phenol) (PVP) dielectric. Furthermore, thin-film transistors based on spin-cast TES-ADT films on PI dielectric exhibited enhanced electrical performance, small hysteresis, and high stability under bias stress with carrier mobility as high as 0.43 cm(2)/Vs and a current on/off ratio of 10(7). (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Performance of Organic Thin-Film Transistors Controlled by Electrode and Device Structures
(2009-04-01)
Yu, Chien-Hsien
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Lei, Tan-Fu
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Liao, Jin-Long
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Yan, Jing-Yi
;
Ho, Jia-Chong
We have fabricated organic thin-film transistors (OTFTs) of top contact (TC) structures using silver electrode based on triethylsilylethynyl anthradithiophene (TES-ADT) with mobility above 0.41 cm(2) s(-1) V(-1), current modulation higher than 5 x 10(7) and sub-threshold swing below 0.65 V/dec.. The electrical characteristics of OTFTs are not only corresponding to the work function of source and drain electrodes materials but also to the surface tension and deposition energy of them. The effects of work function and surface tension dominate the electrical characteristics in bottom contact (BC) device. On the other hand, TC device is affected by deposition energy dominantly.
Perylenetetracarboxylic di-imide-based bottom-contact devices: A study on two kinds of source/drain electrodes, ITO and MoW
(2009-01-01)
Kao, Chia-Chun
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Lin, Pang
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Shen, Yu-Yuan
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Yan, Jing-Yi
;
Ho, Jia-Chong
High-performance bottom-contact devices based on an air-stable n-type organic semiconductor N,N-bis(4-trifluoromethoxybenzyl)-perylene-3,4,9,10-tetracarboxylic di-imide, were fabricated, and the effects of crystal packing on indium tin oxide and molybdenum-tungsten alloy were shown in two different electric characteristics. The estimated work function of indium tin oxide and molybdenum-tungsten alloy were 4.7 and 5.0eV. The calculated lowest unoccupied molecular orbital energy level of the organic material was 3.7eV. Transistors with indium tin oxide bottom electrodes exhibited a high mobility of 3.37 x 10(2) cm(2) V(-1) s(1), an on/off current ratio of 6.5 x 10(5) and threshold voltage of-4.0 V. (C) 2008 Elsevier B.V All rights reserved.
Polyimide/Ta(2)O(5) nanocomposite gate insulators for enhanced organic thin-film transistor performance
(2011-08-01)
Chen, Liang-Hsiang
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Lin, Pang
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Ho, Jia-Chong
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Lee, Cheng-Chung
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Kim, Choongik
This study reports the preparation and characterization of polyimide/Ta(2)O(5) nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta(2)O(5) precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2-3 with carrier mobility values as high as 0.38 cm(2)/Vs. (C) 2011 Elsevier B.V. All rights reserved.
Polyimide/Ta2O5 nanocomposite gate insulators for enhanced organic thin-film transistor performance
(2011-08-01)
Chen, Liang-Hsiang
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Lin, Pang
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Ho, Jia-Chong
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Lee, Cheng-Chung
;
Kim, Choongik
This study reports the preparation and characterization of polyimide/Ta2O5 nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta2O5 precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2-3 with carrier mobility values as high as 0.38 cm(2)/Vs. (C) 2011 Elsevier B.V. All rights reserved.
Silver nanowire-polymer composite electrode for high performance solution-processed thin-film transistors
(2012-10-01)
Chen, Liang-Hsiang
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Lin, Pang
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Chen, Ming-Chou
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Huang, Peng-Yi
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Kim, Choongik
Silver nanowires (AgNWs)/poly-(3,4-ethylenedioxythiophene/polystyrene sulphonate) (PEDOT:PSS) composite films as conductive electrode for OTFTs were prepared, and their optical and electrical properties were investigated. The conductive composite films used in this study afforded low sheet resistance of <140 Omega/sq and transmittance as high as 70% in the visible region. For the composite film with 0.1 wt.% of AgNWs, contact resistance as low as 2.7 x 10(4) Omega cm was obtained, as examined by Transfer length model (TLM) analysis, and work function of the corresponding film was 5.0 eV. Furthermore, the composite films were employed as source and drain electrodes for top-gate/bottom-contact organic thin-film transistors (OTFTs) based on solution-processed 5,11-bistriethylsilylethynyl anthradithiophene (TES-ADT) as organic semiconductor, and the resulting device showed high electrical performance with carrier mobility as high as 0.21 cm(2)/V s. (C) 2012 Elsevier B.V. All rights reserved.
Solid-state structure of the naphthalene-based n-type semiconductor, and performance improved with Mo-based source/drain electrodes
(2008-05-01)
Kao, Chia-Chun
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Lin, Pang
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Shen, Yu-Yuan
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Yan, Jing-Yi
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Ho, Jia-Chong
The synthesis, single-crystal structures, and device performance of novel naphthalene-diimide are described. The crystal structure has revealed the importance of a withdrawing group on solid-state packing. Metal molybdenum use as source/drain (S/D) electrodes can improve the performance of the bottom-contact device. The bottom-contact device based on a material of N,N'-bis (4-trifluoromethoxybenzyl) naphthalene-1,4,5,8-tetracarboxylic acid diimide has a high mobility of 3.58 x 10(-2) cm(2) V-1 s(-1), a threshold voltage of 1.3 V, and an on/off current ratio of 5.2 x 10(5). (c) 2008 Published by Elsevier B.V.
Thermal Behavior and self-heating effect in pentacene-based thin film transistors
(2005)
Wei, Shih-Chiang
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Lee, Po-Tsung
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Zan, Hsiao-Wen
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Lee, Cheng-Chung
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Ho, Jia-Chong
Pentacene-based thin film transitors are characterized at four different substrate tempertures (25 degrees C, 45 degrees C, 65 degrees C, and 85 degrees C). The temperature dependence of mobility, threshold voltage, and drain current at and above room temperature is investigated, and self-heating effect is observed and discussed.