Browsing by Author "Hwang, Jenn-Chang"

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Carbon attachment on the aluminum nitride gate dielectric in the pentacene-based organic thin-film transistors
(2009-03-15)
Zan, Hsiao-Wen
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Chou, Cheng-Wei
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Wang, Chung-Hwa
;
Song, Ho-Tsung
;
Hwang, Jenn-Chang
This study presents carbon attachment on an aluminum nitride (AlN) gate dielectric to improve the device performance of pentacene-based organic thin-film transistors (OTFTs). This approach produces high OTFT performance on an aged AlN surface. A high mobility of 0.67 cm(2)/V s was achieved on an AlN surface aged for 14 days, compared to a mobility of 0.05 cm(2)/V s on an as-deposited AlN surface. This improvement in device performance is correlated with carbon attachment on the AlN surface, which lowers surface energy. The lowered surface energy made the surface less polar, as measured by a contact angle instrument. The chemical composition of the aged AlN surface was analyzed using x-ray photoelectron spectroscopy before pentacene deposition. Enhanced C=C bonding at 284.5 eV was observed on the aged AlN surface. These enhanced C=C bonds favored the growth of large pentacene islands in the initial growth stage, which may improve OTFT device performance.
Controllable alignment modes of nematic liquid crystals on argon ion beam bombarded polyimide films
(2007)
Wu, Hsin-Ying
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Wang, Chih-Chieh
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Pan, Ru-Pin
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Tang, Tsung-Ta
;
Chang, Shao-Ju
We investigate the alignment properties of nematic liquid crystal on polyimide films bombarded by Ar ion beams with a small diode sputter type ion-beam source. The alignments of nematic liquid crystal 4'-n-pentyl-4-cyanobiphenyl (5CB) on treated polyimide surface are characterized by using polarizing optical microscope and conoscope. The polyimide surfaces are also studied by using atomic force microscope and x-ray photoemission spectroscopy. We have demonstrated that the polyimide surface treated by Ar ion beams can give both homogeneous and homeotropic alignments with the same ion beam apparatus but varying the energy of ion beam and the bombarding time.
Crystal Quality of 3C-SiC Influenced by the Diffusion Step in the Modified Four-Step Method
(2010)
Chen, Wei-Yu
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Wang, Wei-Lin
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Liu, Jui-Min
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Chen, Chien-Cheng
;
Hwang, Jenn-Chang
The atomic arrangement and bonding characteristics of void-free 3C-SiC/Si(100) grown by the modified four-step method are presented. Without the diffusion step, Si-C bonds are partially formed in the as-carburized layer on Si(100). The ratio of C-C bonds to Si-C bonds is about 7:3, which can be lowered to about 1:9 after the diffusion step at 1350 degrees C for 5 min or at 1300 degrees C for 7 min according to C 1s core level spectra. The residual C-C bonds cannot be removed, which is associated with an irregular atomic arrangement (amorphous) located either at the 3C-SiC/Si(100) interface or at the intersection of twin boundaries in the 3C-SiC buffer layer based on the lattice image taken by transmission electron microscope. The diffusion step helps the formation of Si-C bonds more completely and results in a SiC buffer layer of high quality formed on Si(100) before the growth step. However, twins and stacking faults still appear in the 3C-SiC buffer layer after the diffusion step. The formation mechanism of the 3C-SiC buffer layer is proposed and discussed.
High performance electric-double-layer amorphous IGZO thin-film transistors gated with hydrated bovine serum albumin protein
(2015-09-01)
Chen, Shih-Han
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Liu, Hung-Chuan
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Lee, Chun-Yi
;
Gan, Jon-Yiew
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Zan, Hsiao-Wen
Device performance of amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) has been improved greatly by using bovine serum albumin (BSA) as the top gate dielectric. BSA is a natural protein with acidic and basic amino acid residues, which is easily hydrated in air ambient. A typical a-IGZO TFT with hydrated BSA as the top gate dielectric exhibits a field-effect mobility (mu(FE)) value of 113.5 cm(2) V-1 s(-1) in saturation regime and a threshold voltage (V-TH) value of 0.25 V in air ambient. The excellent device performance can be well explained by the formation of electric double layers (EDLs) near the interfaces of a-IGZO/hydrated BSA and hydrated BSA/gate electrode. The reliability issue of a-IGZO TFTs gated with hydrated BSA has been also investigated by using the life time test without encapsulation. The V-TH value increases and mu(FE,sat) value reduces slightly for the a-IGZO TFT and remain stabilized over 60 days. (C) 2015 Elsevier B.V. All rights reserved.
Highly textured ZnO:B films grown by low pressure chemical vapor deposition for efficiency enhancement of heterojunction silicon-based solar cells
(2013-09-01)
Hsiao, Jui-Chung
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Chen, Chien-Hsun
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Yang, Hung-Jen
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Wu, Chien-Liang
;
Fan, Chia-Ming
This paper demonstrates the growth of highly-textured boron-doped ZnO (ZnO:B) film by using low-pressure chemical-vapor-deposition (LPCVD) for efficient light harvesting and carrier collection in heterojunction silicon-based (HJS) solar cells. The optical and electrical characteristics have been optimized versus the substrate temperature and B2H6 flow rate for tradeoffs among the sheet resistance, free-carrier absorption, and optical transmission of blue/green wavelengths. A HJS solar cell with a 1.6-mu m-thick ZnO:B film achieves a high power conversion efficiency of 16.30% and fill factor of 78.05%, compared to 15.64% and 72.17%, respectively, from a counterpart with a conventional 80-nm-thick indium tin oxide layer. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Methane Exposure on the Aluminum Nitride Gate Dielectric in Pentacene-Based Organic Thin-Film Transistors
(2009)
Chou, Cheng-Wei
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Zan, Hsiao-Wen
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Wang, Chung-Hwa
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Chen, Wei-Tsung
;
Tsai, Li-Shiuan
The device performance of a pentacene-based organic thin-film transistor (OTFT) fabricated on an aluminum nitride (AlN) surface can be improved by exposing AlN to a methane (CH(4)) gas before device fabrication. The mobility of the OTFT was enhanced from 0.046 to 0.924 cm(2)/V s by exposing AlN to CH(4). Its threshold voltage was reduced from -4.5 to -1.9 V. After the CH(4) exposure, the reduced surface energy of AlN was correlated with the improvement of the OTFT performance. The reduction of surface energy was correlated with the replacement of O-C=O bonds by C-O bonds and hydrocarbon (CH(x)) on the AlN surface. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3182823] All rights reserved.
Pentacene patterning on aluminum nitride by water dipping
(2008)
Zan, Hsiao-Wen
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Chou, Cheng-Wei
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Wang, Chung-Hwa
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Yen, Kuo-Hsi
;
Hwang, Jenn-Chang
This study reports a pentacene patterning method that can be combined with conventional lithography to pattern pentacene film. The aluminum nitride (AlN) surface was patterned using a conventional photolithography process and then treated with oxygen (O(2)) plasma on uncovered AlN to modify surface polarity. Following pentacene deposition, the sample was dipped in water to remove pentacene from the O(2) plasma-treated area. The O(2) plasma-treated AlN surface was analyzed using X-ray photoelectron spectroscopy (XPS) before pentacene deposition. The polar surface energy changed from 13.2 to 114.4 mJ/m(2) when the AlN surface was treated with O(2) plasma at 100 W for 10 min. The polar surface energy was attributed to the increase of Al-O bonds on the surface based on XPS measurements. The intrusion energy of water was enhanced from 34.5 to 140.4 mJ/m(2) due to the polar surface energy induced by the O(2) plasma treatment. The enhancement of water intrusion energy and the polar surface energy explains the water-removable pentacene patterning mechanism. (C) 2008 The Electrochemical Society.
Plasma device for liquid crystal alignment
(2008-06-05)
Chao, Ru-Pin
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Wu, Hsin-Ying
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Wang, Chih-Chieh
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Chang, Shao-Ju
;
Hwang, Jenn-Chang
A device utilizes a plasma for a liquid crystal alignment. The alignment is processed in a vacuum chamber in a simple way. A general chemical vapor deposition is coordinated to reduce cost. The present invention is a novel contactless process avoiding particle contamination, residual static charge and scratch. And multiple are as of the present invention can be used for alignment.
Solution-based silk fibroin dielectric in n-type C-60 organic field-effect transistors: Mobility enhancement by the pentacene interlayer
(2013-12-02)
Tsai, Li-Shiuan
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Hwang, Jenn-Chang
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Lee, Chun-Yi
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Lin, Yi-Ting
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Tsai, Cheng-Lun
A pentacene interlayer of 2 nm thick is inserted between fullerene (C-60) and the solution-based silk fibroin dielectric in C-60 organic field-effect transistors (OFETs). The pentacene interlayer assists to improve crystal quality of the C-60 layer, leading to the increase of field-effect mobility (mu(FE)) from 0.014 to 1 cm(2) V-1 s(-1) in vacuum. The mu(FE) value of the C-60 OFET is further enhanced to 10 cm(2) V-1 s(-1) when the OFET is exposed to air in a relative humidity of 55%. Generation of mobile and immobile charged ions in solution-based silk fibroin in air ambient is proposed. (C) 2013 AIP Publishing LLC.