Browsing by Author "Yang, Feng-Yu"

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High-performance poly(3-hexylthiophene) top-gate transistors incorporating TiO(2) nanocomposite dielectrics
(2010-01-01)
Yang, Feng-Yu
;
Hsu, Meei-Yu
;
Hwang, Gue-Wuu
;
Chang, Kuo-Jui
;
電子工程學系及電子研究所
This paper describes the fabrication of top-gate P3HT organic field effect transistors (OFETs) incorporating polymer/TiO(2) nanocomposite bilayer dielectrics. The TiO(2) nanocomposite comprised PVP, the cross-linking agent PMF, and TiO(2) nanoparticles (NPs), which possessed rod-like anatase structures and were solution-processable using polar solvents; thus, the composite dielectric solutions were easy to be prepared for the use in top-gate OFET devices without damaging and dissolution of the underlying P3HT film. SEM and AFM images revealed the high uniformity of the nanocomposite films. To determine the effects of the composite dielectrics with/without TiO(2) on the performance of the OFET devices, we inserted a buffer layer of PMMA between the semiconductor layer and the gate dielectric to maintain a constant semiconductor-dielectric interface. The device incorporating the PMMA/TiO(2) nanocomposite bilayer gate dielectric operated effectively at supply voltages within 20 V, with a good mobility (mu) of 1.5 x 10(-2) cm(2) V(-1) s(-1), which was three times greater than that of the devices featuring the PMMA/PVP/PMF dielectric; the on/off ratio of nanocomposite device (8.6 x 10(6)) was significantly better than that of the PVP/PMF device (1.5 x 105). The PMMA/TiO(2) nanocomposite was also performed acceptably at supply voltages of less than 10 V. The performance of the OFET incorporating a single dielectric layer of the TiO(2) nanocomposite (mu = 0.001 cm(2) V(-1) s(-1); on/off ratio = 5.7 x 10(2)) was inferior to those of the bilayer gate dielectric devices. (C) 2009 Elsevier B.V. All rights reserved.
High-performance poly(3-hexylthiophene) top-gate transistors incorporating TiO2 nanocomposite dielectrics
(2010-01-01)
Yang, Feng-Yu
;
Hsu, Meei-Yu
;
Hwang, Gue-Wuu
;
Chang, Kuo-Jui
;
電子工程學系及電子研究所
This paper describes the fabrication of top-gate P3HT organic field effect transistors (OFETs) incorporating polymer/TiO2 nanocomposite bilayer dielectrics. The TiO2 nanocomposite comprised PVP, the cross-linking agent PMF, and TiO2 nanoparticles (NPs), which possessed rod-like anatase structures and were solution-processable using polar solvents; thus, the composite dielectric solutions were easy to be prepared for the use in top-gate OFET devices without damaging and dissolution of the underlying P3HT film. SEM and AFM images revealed the high uniformity of the nanocomposite films. To determine the effects of the composite dielectrics with/without TiO2 on the performance of the OFET devices, we inserted a buffer layer of PMMA between the semiconductor layer and the gate dielectric to maintain a constant semiconductor-dielectric interface. The device incorporating the PMMA/TiO2 nanocomposite bilayer gate dielectric operated effectively at supply voltages within 20 V, with a good mobility (mu) of 1.5 x 10(-2) cm(2) V-1 s(-1), which was three times greater than that of the devices featuring the PMMA/PVP/PMF dielectric; the on/off ratio of nanocomposite device (8.6 x 10(6)) was significantly better than that of the PVP/PMF device (1.5 x 105). The PMMA/TiO2 nanocomposite was also performed acceptably at supply voltages of less than 10 V. The performance of the OFET incorporating a single dielectric layer of the TiO2 nanocomposite (mu = 0.001 cm(2) V-1 s(-1); on/off ratio = 5.7 x 10(2)) was inferior to those of the bilayer gate dielectric devices. (C) 2009 Elsevier B.V. All rights reserved.
High-performance poly(3-hexylthiophene) transistors with thermally cured and photo-cured PVP gate dielectrics
(2008)
Yang, Feng-Yu
;
Chang, Kuo-Jui
;
Hsu, Meei-Yu
;
Liu, Cheng-Chin
;
電子工程學系及電子研究所
We have fabricated poly(3-hexylthiophene) organic field-effect transistors (P3HT-OFETs) with either high-temperature (200 degrees C) thermally cured PVP gate dielectrics or low-temperature (120 degrees C) photo-cured PVP gate dielectrics. We prepared the thermally cured PVP dielectric layer from a blend of poly(4-vinylphenol) (PVP) and poly(melamine-co-formaldehyde) (PMF); the photo-cured PVP dielectric formulation contained an additional photo-acid generator (PAG), which allowed the temperature for the cross-linking reaction to be reduced. We examined the intrinsic dielectric properties (e.g., the dielectric constant, the electrical insulating properties) and surface properties (e.g., morphology, surface energy) of the formulations loaded with various amounts of PAG (from 0 to 2.4 wt%). The P3HT-OFETs with the thermally cured PVP gate dielectrics exhibited an excellent carrier mobility of ca. 0.1 cm(2) V(-1) s(-1), a sub-threshold swing of 2.0 V decade(-1), and an on/off ratio of 1.2 x 10(4). For comparison, the P3HT-OFET devices with the photo-cured PVP gate dielectrics also exhibited good electrical characteristics, including carrier mobilities as high as 0.06 cm(2) V(-1) s(-1), sub-threshold swings as low as 1.4 V decade(-1), and on/off ratios as large as 3.0 x 10(4). To take advantage of the photo-cured PVP films, we also fabricated OFETs on a flexible, cheap ITO/PET substrate.
Low-operating-voltage polymeric transistor with solution-processed low-k polymer/high-k metal-oxide bilayer insulators
(2008-10-01)
Yang, Feng-Yu
;
Chang, Kuo-Jui
;
Hsu, Meei-Yu
;
Liu, Cheng-Chin
;
電子工程學系及電子研究所
We have successfully demonstrated a polymeric semiconductor-based transistor with low-k polymer/high-k metal-oxide (TiO2) bilayer as gate dielectric. The TiO2 layers are readily processable from solution and cured at low temperature, instead of traditionally sputtering or high temperature sintering process, thus may suitable for a low-cost organic field effect transistors (FETs) manufacture. The low-k polymer capped on TiO2 layer could further smooth the TiO2 dielectric surface and suppress the leakage current from grain boundary of TiO2 films. The resulting unpatented P3HT-OFETs could operate with supply voltage less than 10 V and the mobility and threshold voltage were 0.0140 cm(2)/V s and 1.14 V, respectively. The on/off ratio was 1.0 x 10(3). (C) 2008 Elsevier B.V. All rights reserved.
Self-patterning of high-performance thin film transistors
(2009-08-01)
Chang, Kuo-Jui
;
Yang, Feng-Yu
;
Liu, Cheng-Chin
;
Hsu, Meei-Yu
;
Liao, Ta-Chuan
We have developed a technique for the preparation of thin film transistors (TFTs) through the self-patterning of various organic and inorganic materials via solution processing using a wide range of solvents. To obtain selectively self-patterned layers, we treated the oxide dielectric with two-phase patterned self-assembled monolayers of hexamethyldisilazane (HMDS) and octyltrichlorosilane. The conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid) in water and the dielectric polymer poly(vinyl phenol) in propylene glycol methyl ether acetate were both selectively deposited and patterned on the HMDS regions with high-quality feature shapes. When source and drain electrodes were patterned on the bottom-gate oxide wafer, we also self-patterned organic and inorganic semiconductors around the channel (HMDS) regions. These TFT devices exhibited moderate to good electronic characteristics. This method has great potential for the economical full solution processing of large-area electronic devices. The selectivity in the patterning phenomena can be understood in terms of surface energy interactions. (C) 2009 Elsevier B.V. All rights reserved.