Browsing by Author "Lin, Yung-Sheng"

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Copper phthalocyanine buffer layer to enhance the charge injection in organic thin-film transistors
(2007-02-12)
Chen, Fang-Chung
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Kung, Li-Jen
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Chen, Tung-Hsien
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Lin, Yung-Sheng
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光電工程學系
Copper phthalocyanine (CuPC) has been used as the buffer layer for source and drain electrodes to improve the performance of organic thin-film transistors. The mobility was improved by almost onefold after the modification. By incorporating with CuPC, the contact resistance was reduced, deduced from the line-transfer method. The higher hole current observed in the hole-only diode after adding CuPC further confirms the improvement of hole-injection efficiency. It is concluded that the device improvement is attributed to the reduction of contact resistance, which resulted from the Fermi level pinning at the induced gap states at the Au/CuPC interface. (c) 2007 American Institute of Physics.
Efficient hole-injection in highly transparent organic thin-film transistors
(2007)
Chen, Fang-Chung
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Lin, Yung-Sheng
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Chen, Tung-Hsien
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Kung, Li-Jen
;
光電工程學系
Highly transparent organic thin-film transistors (OTFTs) based on pentacene have been demonstrated successfully. By inserting one layer of metal oxides between the transparent electrodes and the semiconductor, the device performance was enhanced dramatically. Meanwhile, the average transmittance, which is as high as 72.2%, in the visible region has been realized. The high transmittance is among the highest values reported for thin-film transistors made of organic semiconductors. Furthermore, from the results of the transfer line method, it is realized that device enhancement is contributed from reduction of the contact resistance. (c) 2007 The Electrochemical Society.
GATE DIELECTRIC STRUCTURE AND AN ORGANIC THIN FILM TRANSISTOR BASED THEREON
(2007-09-20)
Chen, Fang-Chung
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Chuang, Chiao-Shun
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Lin, Yung-Sheng
A gate dielectric structure and an organic thin film transistor based thereon, wherein the gate dielectric structure comprises: an organic-inorganic composite layer and an organic insulation layer, and the gate dielectric structure is applied to an organic thin film transistor. As the organic-inorganic composite layer of the gate dielectric structure has an organic insulation matrix blended with inorganic surface-modified particles, it can achieve a high dielectric constant. Further, as the organic insulation layer can modify the surface of the organic-inorganic composite layer, not only the leakage current is reduced, but also the crystalline structure of the organic semiconductor layer becomes more orderly. Thus, the carrier mobility is raised, the current output of the element is increased, and the performance of the element is also greatly enhanced.
Graphene-based chips fabricated by ultraviolet laser patterning for an electrochemical impedance spectroscopy
(2016-04-01)
Tseng, Shih-Feng
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Haiso, Wen-Tse
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Cheng, Pi-Ying
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Chung, Chien-Kai
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Lin, Yung-Sheng
This study aims to develop graphene-based impedance chips for an electrochemical impedance instrument fabricated by ultraviolet (UV) laser patterning. The finger-like electrode structure on multilayer graphene films coated on glass substrates was performed in a one-cycle laser patterning process. After a series of laser ablated line tests, the ablated line widths increased with increasing laser fluences. The optimal laser patterning parameters involved the laser fluence of 3.4 J/cm(2), scanning speed of 600 mm/s, and pulse repetition frequency of 100 kHz to remove completely a graphene electrode layer without damaging glass substrate. The patterned regions had no significant heat-affacted zones (HAZs) due to graphene materials with high thermal diffusivity. To clarify graphene removal completely, the patterned regions on graphene/glass substrates were detected by a Raman microscope. The developed impedance-sensing chips had been successfully applied to detect the phase separation for emulsions containing emulsifiers with 15%, 17.5%, and 20% Polysorbate 80 (Tween 80) concentrations. We found that the separation time increased with increasing the emulsifier concentration. (C) 2015 Elsevier B.V. All rights reserved.
Hydrophobic Templates with Rough Patterns Fabricated by Laser Micromachining for Liquid Droplets Generation
(2011)
Tseng, Shih-Feng
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Huang, Kuo-Cheng
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Chiang, Donyau
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Chen, Ming-Fei
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Hsiao, Sheng-Yi
This paper presents an approach to utilize high precision pulsed Nd:YAG laser to fabricate a rough array-pattern on a soda-lime glass plate by a laser-induced backside writing (LIBW) process, and a laser-induced plasma assisted ablation (LIPAA) technique. The current study investigates the effect of process parameters such as single-shot laser exposure time and number of passes on the material removal rate. After depositing 695 nm thick Teflon thin film on the glass plate, the surface of the laser micro-machined template becomes hydrophobic. The surface roughness, annular groove profile and surface micrograph were measured by an atomic force microscope, a profilometer, and a scanning electron microscope, respectively. A uniform liquid droplet by the sessile drop method is generated on the hydrophobic template. Droplet characteristics, such as contacted angle, size, and shape, are measured with a surface tension analyzer and microscope. This work also discusses the relationship between the formed droplets and the process recipe of the micro-machined template. The proposed approach can apply to future for uniform lens array formation.
Laser structuring of parallel electrode array on graphene/glass substrates for rapid inspections of moisturizing efficacy
(2017-08-01)
Tseng, Shih-Feng
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Haiso, Wen-Tse
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Cheng, Pi-Ying
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Lin, Yung-Sheng
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Chang, Tien-Li
This research aims to structure thin layers of graphene materials for impedance sensing chips with a parallel electrode array and to investigate the interaction between nanosecond pulsed Nd:YVO4 lasers and graphene films coated on glass substrates. The optimal laser structuring conditions consisted of pulse repetition rate of 100 kHz, the scanning speed of two galvano scanners of 600 mm/s, the laser fluence of 3.4 J/cm(2), and parallel lines of the laser processing path with the line-scan spacing of 1 mu m in one-cycle process to produce the parallel electrode structures. The surface morphology, cross-sectional profile, optical spectra, and material characterizations on graphene/glass substrates were detected by a confocal laser scanning microscope, a scanning electron microscope (SEM), a spectrophotometer, and a Raman spectroscopy, respectively. The parallel electrode sensing chips had been successfully used to detect the moisturizing efficacy of solutions containing moisturizers with 0, 3, 6, and 9 wt% 1,3-Butylene Glycol concentrations. The experimental results showed that the electrochemical impedance spectroscopy combined with graphene sensing chips had high sensitivity and saving time than weight loss of solutions detected by the precision electronic balance.
Low-voltage organic thin-film transistors with polymeric nanocomposite dielectrics
(2006-10-01)
Chen, Fang-Chung
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Chuang, Chiao-Shun
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Lin, Yung-Sheng
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Kung, Li-Jen
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Chen, Tung-Hsien
High performance organic thin-film transistors (OTFTs) incorporated with high dielectric nanoparticles in the dielectric layers have been demonstrated. The dielectric insulator consists of cross-linked poly-4-vinylphenol (PVP) and titanium dioxide (TiO2) nanoparticles. In order to obtain highly soluble TiO2 nanoparticles in organic solutions, the surface of nanoparticles was modified with organosiloxane. Moreover, the concern of higher leakage current, while using the high dielectric nanocomposite insulators, has been overcome by further applying another poly(alpha-methylstrylene) layer. As a result. we have demonstrated low-voltage OTFTs, which can be operated within 10 V. (C) 2006 Elsevier B.V. All rights reserved.
Microfluidic Synthesis of Microfibers for Magnetic-Responsive Controlled Drug Release and Cell Culture
(2012-03-28)
Lin, Yung-Sheng
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Huang, Keng-Shiang
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Yang, Chih-Hui
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Wang, Chih-Yu
;
Yang, Yuh-Shyong
This study demonstrated the fabrication of alginate microfibers using a modular microfluidic system for magnetic-responsive controlled drug release and cell culture. A novel two-dimensional fluid-focusing technique with multi-inlets and junctions was used to spatiotemporally control the continuous laminar flow of alginate solutions. The diameter of the manufactured microfibers, which ranged from 211 mm to 364 mm, could be well controlled by changing the flow rate of the continuous phase. While the model drug, diclofenac, was encapsulated into microfibers, the drug release profile exhibited the characteristic of a proper and steady release. Furthermore, the diclofenac release kinetics from the magnetic iron oxide-loaded microfibers could be controlled externally, allowing for a rapid drug release by applying a magnetic force. In addition, the successful culture of glioblastoma multiforme cells in the microfibers demonstrated a good structural integrity and environment to grow cells that could be applied in drug screening for targeting cancer cells. The proposed microfluidic system has the advantages of ease of fabrication, simplicity, and a fast and low-cost process that is capable of generating functional microfibers with the potential for biomedical applications, such as drug controlled release and cell culture.
Novel electrode architecture for transparent organic thin-film transistors
(2006)
Chen, Fang-Chung
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Chen, Tung-Hsien
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Lin, Yung-Sheng
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光電工程學系
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Department of Photonics
One novel electrode-architecture has been adapted to fabricate transparent OTFTs. The device has more than 70% transmittance, yet reminds high performance. Furthermore, we also use transger line method to prove that the device performance enhancement indeed contributes from the reduction of the contact resistances. It is anticipated that the transparent OTFTs would be very suitable to be the driving circuits for liquid crystal displays (LCDs).
Organic thin-film transistors based on nanocomposite gate insulators for high-current driving applications
(2005)
Chuang, Chiao-Shun
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Lin, Yung-Sheng
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Kung, Li-Jen
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Chen, Dong-Sian
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Chen, Fang-Chung
Highly performance organic thin-film transistors (OTFTs) incorporated with nanoparticles in the dielectric insulators have been demonstrated. The dielectric layers consist of cross-linked poly-4-vinylphenol (PVP) and high dielectric titanium dioxide (TiO(2)) nanoparticles. In order to increase the solubility of TiO(2) nanoparticles in organic solutions, the surface of natioparticles was modified with organosilozane. Moreover, the concern of higher leakage current, while using the nano-composite insulators, has been overcome by P8 treatment. In addition, several models, which have been used to describe the dielectric behavior of composite materials, are also discussed.
Photocurrent suppression of transparent organic thin film transistors
(2007-12-01)
Chuang, Chiao-Shun
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Tsai, Shu-Ting
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Lin, Yung-Sheng
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Chen, Fang-Chung
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Shieh, Hang-Ping D.
Organic thin-film transistors (OTFTs) with high transmittance and low photosensitivity have been demonstrated. By using titanium dioxide nanoparticles as the additives in the polymer gate insulators, the level of device photoresponse has been reduced. The device shows simultaneously a high transparence and a minimal threshold voltage shift under white light illumination. It is inferred that the localized energy levels deep in the energy gap of pentacene behave as the recombination centers, enhancing substantially the recombination process in the conducting channel of the OTFFs. Therefore, the electron trapping is relieved and the shift of threshold voltage is reduced upon illumination.
Surface wettability of silicon substrates enhanced by laser ablation
(2010-11-01)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Chen, Ming-Fei
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Huang, Kuo-Cheng
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Hsiao, Sheng-Yi
Laser-ablation techniques have been widely applied for removing material from a solid surface using a laser-beam irradiating apparatus. This paper presents a surface-texturing technique to create rough patterns on a silicon substrate using a pulsed Nd:YAG laser system. The different degrees of microstructure and surface roughness were adjusted by the laser fluence and laser pulse duration. A scanning electron microscope (SEM) and a 3D confocal laser-scanning microscope are used to measure the surface micrograph and roughness of the patterns, respectively. The contact angle variations between droplets on the textured surface were measured using an FTA 188 video contact angle analyzer. The results indicate that increasing the values of laser fluence and laser pulse duration pushes more molten slag piled around these patterns to create micro-sized craters and leads to an increase in the crater height and surface roughness. A typical example of a droplet on a laser-textured surface shows that the droplet spreads very quickly and almost disappears within 0.5167 s, compared to a contact angle of 47.9A degrees on an untextured surface. This processing technique can also be applied to fabricating Si solar panels to increase the absorption efficiency of light.
Surface wettability of silicon substrates enhanced by laser ablation
(2010-11-01)
Tseng, Shih-Feng
;
Hsiao, Wen-Tse
;
Chen, Ming-Fei
;
Huang, Kuo-Cheng
;
Hsiao, Sheng-Yi
Laser-ablation techniques have been widely applied for removing material from a solid surface using a laser-beam irradiating apparatus. This paper presents a surface-texturing technique to create rough patterns on a silicon substrate using a pulsed Nd:YAG laser system. The different degrees of microstructure and surface roughness were adjusted by the laser fluence and laser pulse duration. A scanning electron microscope (SEM) and a 3D confocal laser-scanning microscope are used to measure the surface micrograph and roughness of the patterns, respectively. The contact angle variations between droplets on the textured surface were measured using an FTA 188 video contact angle analyzer. The results indicate that increasing the values of laser fluence and laser pulse duration pushes more molten slag piled around these patterns to create micro-sized craters and leads to an increase in the crater height and surface roughness. A typical example of a droplet on a laser-textured surface shows that the droplet spreads very quickly and almost disappears within 0.5167 s, compared to a contact angle of 47.9A degrees on an untextured surface. This processing technique can also be applied to fabricating Si solar panels to increase the absorption efficiency of light.
Synthesis of uniform core-shell gelatin-alginate microparticles as intestine-released oral delivery drug carrier
(2014-02-01)
Huang, Keng-Shiang
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Yang, Chih-Hui
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Kung, Chao-Ping
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Grumezescu, Alexandru Mihai
;
Ker, Ming-Dou
A core-shell gelatin-alginate composite used for intestine-released oral delivery drug carrier was synthesized through microfluidic technique. At the fixed continuous phase flow rate, the size of the core-shell gelatin-alginate microparticles increases with the dispersed phase flow rate, and monodispersity can be retained (the variation coefficient for the diameter distribution can be kept less than 10%). The fabricated microparticles could remain intact in gastric juice for at least 3 h, indicating that the gelatin core could be well protected by alginate shell in acid environment. However, the alginate shell of the microparticles would swell or collapse in alkali environment in half an hour, assuring the controlled drug release in intestinal juice. The fabricated uniform core-shell gelatin-alginate microparticles were potential as pH-responsive drug carriers.
Transparent organic thin-film transistors with reduced photosensitivity
(2007)
Chuang, Chiao-Shun
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Tsai, Shu-Ting
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Lin, Yung-Sheng
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Chen, Fang-Chung
;
Shieh, Han-Ping D.
Organic thin-film transistors ( OTFTs) with reduced-photosensitivity have been made by blending titanium dioxide (TiO2) nanoparticles into the polymer dielectric layer. The minimized shift of threshold voltage and more stable photocurrent are attributed to the introduction of recombination centers induced by the doping of TiO2 nanoparticles. The localized energy levels deep in the energy gap and away from highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of pentacene may serve as the recombination centers, which can enhance substantially the recombination process in the OTFTs. In addition, it was found that the OTFTs with the above mentioned composite dielectric layers possess transparent and anti-glare functions comparable to the conventional devices.
Transparent OTFTs with color filtering functional gate insulators
(2007)
Chuang, Chiao-Shun
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Tsai, Shu-Ting
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Lin, Yung-Sheng
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Cheng, Jung-An
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Chen, Fang-Chung
Transparent organic thin-film transistors (OTFTs) impregnated with nanoparticles, organic dyes and pigments in the dielectric insulators were fabricated and analyzed. The colored composite insulators were utilized as the color filter and the dielectric layer of the OTFTs simultaneously to obtain the desired color. It was found that the performance the OTFTs with the above mentioned composite dielectric layers possess color filtering comparable to the conventional devices. In addition, light sensitivity of OTFTs was significantly reduced.