Browsing by Author "Wang, Cheng-Jyun"

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Controllable Ink-Jet Printing Technique on Various Channel Width Designs Toward Zinc Oxide-based Thin Film Transistor
(2016)
Wang, Cheng-Jyun
;
Ko, Fu-Hsiang
;
You, Hsin-Chiang
;
Du, Bo-Wei
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材料科學與工程學系
Ink-jet printed (IJP) thin-film transistor (TFT) electronics employing solution processed materials is considered to be the key technique to achieve mask-less, low-cost, large-area, and low temperature fabrication systems. We propose an approach for a direct printing highly transparent conducting oxide material of zinc oxide (ZnO) which the use of semiconductor layer with different transistor channel widths without any photolithography process defined. In this work, we describe the ink-jet printing ZnO TFT with three-types channel widths, and electrical characteristics with low voltage operation, high performance of switch on/off state and low temperature fabrication (200 similar to 300 degrees C). These printed TFT thus represent an uniquely attractive path for realizing high flexibility printed electronics.
Highly Transparent and Surface-Plasmon-Enhanced Visible-Photodetector Based on Zinc Oxide Thin-Film Transistors with Heterojunction Structure
(2019-11-01)
Wang, Cheng-Jyun
;
You, Hsin-Chiang
;
Lin, Kuan
;
Ou, Jen-Hung
;
Chao, Keng-Hsien
Highly transparent zinc oxide (ZnO)-based thin-film transistors (TFTs) with gold nanoparticles (AuNPs) capable of detecting visible light were fabricated through spray pyrolysis on a fluorine-doped tin oxide substrate. The spray-deposited channel layer of ZnO had a thickness of approximately 15 nm, and the thickness exhibited a linear increase with an increasing number of sprays. Furthermore, the ZnO thin-film exhibited a markedly smoother channel layer with a significantly lower surface roughness of 1.84 nm when the substrate was 20 cm from the spray nozzle compared with when it was 10 cm away. Finally, a ZnO and Au-NP heterojunction nanohybrid structure using plasmonic energy detection as an electrical signal, constitutes an ideal combination for a visible-light photodetector. The ZnO-based TFTs convert localized surface plasmon energy into an electrical signal, thereby extending the wide band-gap of materials used for photodetectors to achieve visible-light wavelength detection. The photo-transistors demonstrate an elevated on-current with an increase of the AuNP density in the concentration of 1.26, 12.6, and 126 pM and reach values of 3.75, 5.18, and 9.79 x 10(-7) A with applied gate and drain voltages. Moreover, the threshold voltage (Vth) also drifts to negative values as the AuNP density increases.
Solution processable bilayered gate dielectric towards flexible organic thin film transistors
(2015-04-01)
Singh, Ranjodh
;
Meena, Jagan Singh
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Tsai, I-Hsin
;
Lin, Yen-Ting
;
Wang, Cheng-Jyun
In this study, we have successfully explored the potential of a new bilayer gate dielectric material, composed of Polystyrene (PS), Pluronic P123 Block Copolymer Surfactant (P123) composite thin film and Polyacrylonitrile (PAN) through fabrication of metal insulator metal (MIM) capacitor devices and organic thin film transistors (OTFTs). The conditions for fabrication of PAN and PS-P123 as a bilayer dielectric material are optimized before employing it further as a gate dielectric in OTFTs. Simple solution processable techniques are applied to deposit PAN and PS-P123 as a bilayer dielectric layer on Polyimide (PI) substrates. Contact angle study is further performed to explore the surface property of this bilayer polymer gate dielectric material. This new bilayer dielectric having a k value of 3.7 intermediate to that of PS-P123 composite thin film dielectric (k similar to 2.8) and PAN dielectric (k similar to 5.5) has successfully acted as a buffer layer by preventing the direct contact between the organic semiconducting layer and high k PAN dielectric. The OTFT devices based on alpha,omega-dihexylquaterthiophene (DH4T) incorporated with this bilayer dielectric, has demonstrated a hole mobility of 1.37 x 10(-2) and on/off current ratio of 10(3) which is one of the good values as reported before. Several bending conditions are applied, to explore the charge carrier hopping mechanism involved in deterioration of electrical properties of these OTFTs. Additionally, the electrical performance of OTFTs, which are exposed to open atmosphere for five days, can be interestingly recovered by means of re-baking them respectively at 90 degrees C. (C) 2015 Elsevier B.V. All rights reserved.
The highly electrical performances of flexible indium-zinc-oxide based thin-film transistors on stability improvement by passivation layer
(2017-06-05)
Wang, Cheng-Jyun
;
You, Hsin-Chiang
;
Ko, Fu-Hsiang
;
材料科學與工程學系
;
Department of Materials Science and Engineering
This study examined the use of a simple sol-gel method for synthesizing indium zinc oxide (IZO) films for use as semiconductor channel layers in thin-film transistors (TFTs) fabricated on flexible polyimide substrates. The performance of the flexible IZO-based TFTs was investigated, and the entire process was conducted at a low temperature to ensure the flexibility of the devices. First, transistors were fabricated on a flexible substrate by using silicon nitride and silicon dioxide as dielectric layers to investigate the effect on the on/off current ratios and electronic mobility of the devices. Second, the dielectric layer thickness was increased to enhance device performance, and the devices were finally subjected to bending tests to confirm their flexibility and stability for flexible transistor applications. The study successfully increased the dielectric layer thickness to improve flexible IZO-based TFT performance. (C) 2017 Elsevier B.V. All rights reserved.
Ultraviolet Photodetecting and Plasmon-to-Electric Conversion of Controlled Inkjet-Printing Thin-Film Transistors
(2020-03-01)
Wang, Cheng-Jyun
;
You, Hsin-Chiang
;
Ou, Jen-Hung
;
Chu, Yun-Yi
;
Ko, Fu-Hsiang
Direct ink-jet printing of a zinc-oxide-based thin-film transistor (ZnO-based TFT) with a three-dimensional (3-D) channel structure was demonstrated for ultraviolet light (UV) and visible light photodetection. Here, we demonstrated the channel structures by which temperature-induced Marangoni flow can be used to narrow the channel width from 318.9 +/- 44.1 mu m to 180.1 +/- 13.9 mu m via a temperature gradient. Furthermore, a simple and efficient oxygen plasma treatment was used to enhance the electrical characteristics of switching I-ON/I-OFF ratio of approximately 10(5). Therefore, the stable and excellent gate bias-controlled photo-transistors were fabricated and characterized in detail for ultraviolet (UV) and visible light sensing. The photodetector exhibited a superior photoresponse with a significant increase of more than 2 orders of magnitude larger drain current generated upon UV illumination. The results could be useful for the development of UV photodetectors by the direct-patterning ink-jet printing technique. Additionally, we also have successfully demonstrated that a metal-semiconductor junction structure that enables plasmon energy detection by using the plasmonic effects is an efficient conversion of plasmon energy to an electrical signal. The device showed a significant variations negative shift of threshold voltage under different light power density with exposure of visible light. With the ZnO-based TFTs, only ultraviolet light detection extends to the visible light wavelength.