Browsing by Author "Hsu, Yung-Hsuan"

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Enhancement-mode polymer space-charge-limited transistor with low switching swing of 96 mV/decade
(2011-05-30)
Chao, Yu-Chiang
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Tsai, Hung-Kuo
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Zan, Hsiao-Wen
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Hsu, Yung-Hsuan
;
Meng, Hsin-Fei
In this letter, an enhancement-mode polymer space-charge-limited transistor was realized with a low switching swing of 96 mV/decade, a low operation voltage of 1.5 V, and a high on/off current ratio of 10(4). By investigating the influence of the device's geometric parameters on the transistor characteristics, a low switching swing was obtained by positioning the base electrode at the middle of the channel length and reducing the opening diameter. Simulations of the potential distribution at the central vertical channel verified that the base electrode has the best control over the magnitude of potential barrier, resulting in a low switching swing. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3586255]
Large-area non-close-packed nanosphere deposition by blade coating for vertical space-charge-limited transistor
(2012-12-01)
Chao, Yen-Chu
;
Wang, Kai-Ruei
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Meng, Hsin-Fei
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Zan, Hsiao-Wen
;
Hsu, Yung-Hsuan
In this work, we proposed a fast and controllable blade coating process to form non-close-packed nanosphere structures. We investigated the key to obtain well-distributed non-close-packed PS spheres with blade coating. We utilized the blade-coated nanosphere structure to realize colloidal lithography and fabricate a vertical channel polymer transistor, the space-charge-limited transistor (SCLT). We demonstrated that SCLT utilizing blade-coated nanospheres delivered 13.9 mA/cm(2) at 1.8 V with an on/off current ratio as 45,000. The process of blade-coating nanospheres may facilitate the commercialization of low-cost colloidal lithography. (C) 2012 Elsevier B.V. All rights reserved.
Low operation voltage macromolecular composite memory assisted by graphene nanoflakes
(2013)
Lai, Ying-Chih
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Wang, Di-Yan
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Huang, I-Sheng
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Chen, Yu-Ting
;
Hsu, Yung-Hsuan
The trend towards simple and low-cost processing is one of the most important for macromolecular memory development. Here, bistable memory devices using a solution-processable active material, a mixture of graphene nanoflakes (GNFs) and insulating poly(vinyl alcohol) (PVA), are investigated, which serve as the first example for the direct integration of as-prepared nanoscale graphene into macromolecular memory devices through a one-step low-temperature processing method. Bistable electrical switching behavior and nonvolatile rewritable memory effects are realized by using an indium-tin-oxide/GNF-PVA/silver (ITO/GNF-PVA/Ag) sandwich structure. The resulting device exhibits low operation voltages of +1.4 V (turn-on) and -1.3 V (turn-off), which is promising for memory cells with low power consumptions. The programmable ON- and OFF-states possess a retention time of over 10(4) s and endure up to 10(7) read pulses. The carrier transport in the OFF- and ON-states follows the typical trap-limited space charge limited current and Ohmic laws, respectively. The asymmetric electrical switch behavior is therefore attributed to conducting filaments formed in the PVA layer assisted by the charged GNFs that induce the transition of the conductivity. Our study provides a potential approach for integrating as-prepared graphene into macromolecular memory devices with excellent performances through a simple solution-process.
Multilayer rapid-drying blade coating for organic solar cells by low boiling point solvents
(2014-06-01)
Chen, En-Chen
;
Tsai, Pei-Ting
;
Chang, Bo-Jie
;
Wang, Chun-Ming
;
Meng, Hsin-Fei
A bulk heterojunction organic solar cell with poly(3-hexylthiophene) (P3HT) as the donor and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor is deposited using blade coating on a hot plate at 80 degrees C with hot air of 70 degrees C applied from above. In contrast to the 30 min of conventional dichlorobenzene solvent annealing, the rapid-drying blade coating forms a dry film in 1 s. The fabrication throughput is substantially enhanced. The blade-coated film has a smoother surface roughness of 3.5nm compared with 10.5nm for solvent annealing; however, the desired phase separation in the 50nm scale forms despite the rapid drying. A single layer solar cell exhibits power conversion efficiency of 4.1% with blade coating in chlorobenzene, which is the same as solvent annealing device. A multilayer device with carrier blocking layers fabricated entirely of the less toxic toluene also exhibits efficiency of 4.1%. (C) 2014 The Japan Society of Applied Physics