Browsing by Author "Lin, Hung-Cheng"

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2-V operated flexible vertical organic transistor with good air stability and bias stress reliability
(2017-11-01)
Huang, Kuan-Min
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Lin, Hung-Cheng
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Kawashima, Kazuaki
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Osaka, Itaru
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Zan, Hsiao-Wen
In this work, we demonstrated a vertical organic transistor using air-stable material to exhibit good lifetime, good bias-stress reliability, and low operation voltage on a flexible plastic substrate in air ambient. With a synthesized NTz-based semiconducting polymer, the proposed space-charge-limited transistor (SCLT) delivers high on-off current ratio of 160000 and high output current density of 10 mA/cm(2) at about 2 V. Without encapsulation, the proposed transistor keeps stable current-voltage relationship for 180 days and has only 0.1 V threshold voltage shift after 5000 s bias stress. No significant degradation can be observed after 1000-times bending and a maximum gain of 14 can be obtained when connecting the flexible transistor with a resistor to form an inverter. (C) 2017 Elsevier B.V. All rights reserved.
Achieving good bias stress reliability in organic transistor with vertical channel
(2014-07-01)
Lin, Hung-Cheng
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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物理研究所
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電機學院
Unlike organic field-effect transistor with accumulated channel at dielectric/semiconductor interface, vertical organic transistor exhibits bulk channel current and hence performs good bias stress reliability. Adding self-assemble-monolayer to treat vertical channel can further modulate the charge-trapping surrounding the base electrode and hence influence the bias stress reliability. During 4300-s positive/negative bias stresses, stable output current and on/off ratio are demonstrated by using octadecyltrichlorosilane (OTS)-passivated vertical channel. The good reliability together with the low operation voltage and the high output current make vertical organic transistors capable of driving organic light emitting diode. (C) 2014 Elsevier B.V. All rights reserved.
Blade-coated sol-gel indium-gallium-zinc-oxide for inverted polymer solar cell
(2016-11-01)
Lee, Yan-Huei
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Tsai, Pei-Ting
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Chang, Chia-Ju
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Meng, Hsin-Fei
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Horng, Sheng-Fu
The inverted organic solar cell was fabricated by using sol-gel indium-gallium-zinc-oxide (IGZO) as the electron-transport layer. The IGZO precursor solution was deposited by blade coating with simultaneous substrate heating at 120 degrees C from the bottom and hot wind from above. Uniform IGZO film of around 30 nm was formed after annealing at 400 degrees C. Using the blend of low band-gap polymer poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b: 4,5-b')dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene-)-2-6-diyl)] (PBDTTT-C-T) and [6,6]-Phenyl C71 butyric acid methyl ester ([70] PCBM) as the active layer for the inverted organic solar cell, an efficiency of 6.2% was achieved with a blade speed of 180 mm/s for the IGZO. The efficiency of the inverted organic solar cells was found to depend on the coating speed of the IGZO films, which was attributed to the change in the concentration of surface OH groups. Compared to organic solar cells of conventional structure using PBDTTT-C-T: [70]PCBM as active layer, the inverted organic solar cells showed significant improvement in thermal stability. In addition, the chemical composition, as well as the work function of the IGZO film at the surface and inside can be tuned by the blade speed, which may find applications in other areas like thin-film transistors. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Deep ultraviolet laser direct write for patterning sol-gel InGaZnO semiconducting micro/nanowires and improving field-effect mobility
(2015-05-27)
Lin, Hung-Cheng
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Stehlin, Fabrice
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Soppera, Olivier
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Zan, Hsiao-Wen
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Li, Chang-Hung
Deep-UV (DUV) laser was used to directly write indium-gallium-zinc-oxide (IGZO) precursor solution and form micro and nanoscale patterns. The directional DUV laser beam avoids the substrate heating and suppresses the diffraction effect. A IGZO precursor solution was also developed to fulfill the requirements for direct photopatterning and for achieving semi-conducting properties with thermal annealing at moderate temperature. The DUV-induced crosslinking of the starting material allows direct write of semi-conducting channels in thin-film transistors but also it improves the field-effect mobility and surface roughness. Material analysis has been carried out by XPS, FTIR, spectroscopic ellipsometry and AFM and the effect of DUV on the final material structure is discussed. The DUV irradiation step results in photolysis and a partial condensation of the inorganic network that freezes the sol-gel layer in a homogeneous distribution, lowering possibilities of thermally induced reorganization at the atomic scale. Laser irradiation allows high-resolution photopatterning and high-enough field-effect mobility, which enables the easy fabrication of oxide nanowires for applications in solar cell, display, flexible electronics, and biomedical sensors.
Highly Sensitive Ammonia Sensor with Organic Vertical Nanojunctions for Noninvasive Detection of Hepatic Injury
(2013-03-19)
Dai, Ming-Zhi
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Lin, Yi-Lo
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Lin, Hung-Cheng
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Zan, Hsiao-Wen
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Chang, Kai-Ting
We successfully demonstrate the first solid-state sensor to have reliable responses to breath ammonia of rat. For thioacetamide (TAA)-induced hepatopathy rats, we observe that the proposed sensor can detect liver that undergoes acute-moderate hepatopathy with a p-value less than 0.05. The proposed sensor is an organic diode with vertical nanojunctions produced by using low-cost colloidal lithography. Its simple structure and low production cost facilitates the development of point-of-care technology. We also anticipate that the study is a starting point for investigating sophisticated breath-ammonia-related disease models.
Hydro gel light-guiding conjunction for absorptive type multi-ions detection
(2016-10-05)
Lin, Hung-Cheng
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Yang, Sean Tsungyeh
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Ng, Sock Hoon
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
We present a novel miniaturized solid state sensor produced by embedding two optical fibers in a sensing hydro gel conjunction. The conjunction is a poly (2-hydroxyethyl methacrylate) (poly HEMA) hydro gel mixed with two kinds of selective fluorescent probes. Meso-2,6-Dichlorophenyltripyrrinone (TPN-Cl2) is used to react with zinc ion (Zn2+) and the synthesized "Chemosensor 1" is used to detect ferric ion (Fe3+). This hydro gel conjunction can serve as a light-guiding waveguide that allows light signals to transfer between two fibers. By using a multi-wavelength excitation light, a mixed solution that contains Zn2+ and Fe3+ can be detected in real-time. This miniaturized sensor develops an image for real-time monitoring of Zn2+ and Fe3+ ions in vivo. (C) 2016 Elsevier B.V. All rights reserved.
Porous Organic TFTs for the Applications on Real-Time and Sensitive Gas Sensors
(2011-08-01)
Zan, Hsiao-Wen
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Dai, Ming-Zhi
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Hsu, Ting-Yu
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Lin, Hung-Cheng
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Meng, Hsin-Fei
A pentacene-based organic thin-film transistor (OTFT) with a porous active layer is demonstrated for the first time. The porous OTFT exhibits a fast, sensitive, and reversible response to ammonia gas with a detection limit as 500 ppb, whereas the OTFT without porous structure has a slow response and a poor recovery behavior. The sensing mechanism dominated by the dissociation of hydroxyl groups of the polymer dielectric layer is raised and discussed. The proposed device is the first OTFT-based ammonia sensor with reversible response and high sensitivity in low parts-per-million range. It is promising for the development of a diagnostic breath analysis system.
Review of a solution-processed vertical organic transistor as a solid-state vacuum tube
(2015-05-01)
Lin, Hung-Cheng
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Zan, Hsiao-Wen
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Chao, Yu-Chiang
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Chang, Ming-Yu
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Meng, Hsin-Fei
In this paper, we investigate the key issues in raising the on/off current ratio and increasing the output current. A 1 V operated inverter composed of an enhancement-mode space-charge-limited transistor (SCLT) and a depletion-mode SCLT is demonstrated using the self-assembled monolayer modulation process. With a bulk-conduction mechanism, good bias-stress reliability, and good bending durability are obtained. Finally, key scaling-up processes, including nanoimprinting and blade-coated nanospheres, are demonstrated.
Solid-state sensing tip for zinc ion with double parallel optical fibers embedded in fluorescent hydrogel
(2015-11-01)
Su, Heng-Tsan
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Tsai, May-Jywan
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Chang, Gao-Fong
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Hung, Chen-Hsiung
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Lin, Hung-Cheng
A tip-shaped zinc ion solid-state sensor is made by two parallel optical fibers embedded closely in a sensing hydrogel film. The film is made of poly(2-hydroxyethyl methacrylate) (poly HEMA) hydrogel mixed with the selective fluorescent probe meso-2,6-Dichlorophenyltripyrrinone (TPN-Cl-2) with weight ratio of 0.025 wt%. A 405 nm laser output is sent from one fiber and the 622 nm fluorescence of the doped hydrogel is collected by the second fiber. Each fiber diameter is 370 mu m (core is 300 mu m), whose sum is roughly the tip diameter. The 0.4 cm by 0.5 cm tip has real-time response for zinc ion concentration over 10(-6) M, with marginal signal for 10(-7) M. The tip is inserted inside an oyster and successfully detects the zinc ions, showing that the sensor works in complex body fluid and tolerates certain mechanical stress. To show the potential application for medicine, the sensing film is applied for primary neuronal cultures. We report for the first time zinc ions release at concentration levels 10(-6)-10(-7) M to the medium under stress conditions of ischemia, inflammation, and intoxication. Furthermore, this correlates with the zinc levels detected by biochemical assay. Such sensing tip has great potential for biomedical monitoring ex vivo or in vivo. (C) 2015 Elsevier B.V. All rights reserved.
Solid-state sensing tip for zinc ion with double parallel optical fibers embedded in fluorescent hydrogel (vol 26, pg 429, 2015)
(2016-08)
Su, Heng-Tsan
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Tsai, May-Jywan
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Chang, Gao-Fong
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Hung, Chen-Hsiung
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Lin, Hung-Cheng
Submicron organic thin-film transistors fabricated by film profile engineering method
(2014-07-28)
Wu, Ming-Hung
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Lin, Horng-Chih
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Lin, Hung-Cheng
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
In this work, we explore and demonstrate the feasibility of a film profile engineering (FPE) concept in fabricating pentacene-based organic thin-film transistors (OTFTs) with submicron channel length. The FPE scheme utilizes a suspended bridge built on the wafer and the specific deposition conditions to form thin films with desirable profiles. In order to form a continuous pentacene channel under the bridge, the background pressure of thermal evaporator is adjusted by pumping down the filling N-2 to a specific level. The results show that, by setting the deposition pressure at 3 mtorr, functional operations of OTFTs with channel length ranging from 0.4 to 0.6 mu m are obtained. (C) 2014 AIP Publishing LLC.
Vertical organic transistors withstanding high voltage bias
(2015-04-13)
Chang, Po-Yi
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Peng, Shao-Fu
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Chao, Yu-Chiang
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Lin, Hung-Cheng
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Zan, Hsiao-Wen
Vertical organic transistors withstanding high voltage bias were realized with an insulating silicon monoxide layer obliquely deposited on both the surface of the base electrode and sidewalls of the vertically oriented cylindrical nanopores. No noticeable insulating layer can be observed on the emitter electrode at the bottom of the cylindrical nanopores. The leakage current between the electrodes was suppressed and an operating voltage as high as 15V was obtained. An on/off current ratio of 10(3)-10(4) and an output current density of 5-10 mA/cm(2) were achieved. (c) 2015 AIP Publishing LLC.