Browsing by Author "Ting, Chao-Cheng"

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Electrocatalytic performance of Pt nanoparticles sputter-deposited on indium tin oxide toward methanol oxidation reaction: The particle size effect
(2017-09-15)
Ting, Chao-Cheng
;
Chao, Chih-Hsuan
;
Tsai, Cheng Yu
;
Cheng, I-Kai
;
Pan, Fu-Ming
We sputter-deposited Pt nanoparticles with an average size ranging from 2.0 nm to 8.5 nm on the indium tin oxide (ITO) glass substrate, and studied the effect of the size of Pt nanoparticles on electrocatalytic activity of the Pt/ITO electrode toward methanol oxidation reaction (MOR) in acidic solution. X-ray photoelectron spectroscopy (XPS) reveals an interfacial oxidized Pt layer present between Pt nanoparticles and the ITO substrate, which may modify the surface electronic structure of Pt nanoparticles and thus influences the electrocatalytic properties of the Pt catalyst toward MOR. According to electrochemical analyses, smaller Pt nanoparticles exhibit slower kinetics for CO electrooxidation and MOR. However, a smaller particle size enables better CO tolerance because the bifunctional mechanism is more effective on smaller Pt nanoparticles. The electrocatalytic activity decays rapidly for Pt nanoparticles with a size smaller than 3 nm and larger than 8 nm. The rapid activity decay is attributed to Pt dissolution for smaller nanoparticles and to CO poisoning for larger ones. Pt nanoparticles of 5-6 nm in size loaded on ITO demonstrate a greatly improved electrocatalytic activity and stability compared with those deposited on different substrates in our previous studies. (C) 2017 Elsevier B.V. All rights reserved.
Nearly lattice-matched molybdenum disulfide/gallium nitride heterostructure enabling high-performance phototransistors
(2019-03-01)
Liu, Xinke
;
Chen, Yuxuan
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Li, Dabing
;
Wang, Sheng-Wen
;
Ting, Chao-Cheng
Molybdenum disulfide (MoS2)-based phototransistors are attractive for optical electronics in a large-scale size, such as transparent touch screens. However, most of the work done over the past decade has been on an opaque SiO2/Si wafer with a small size (micrometer to millimeter). In this work, a large-scale multilayer MoS2-based phototransistor has been fabricated on a transparent freestanding gallium nitride (GaN) wafer using a scalable chemical vapor deposition method. Due to the near lattice match and small thermal expansion mismatch between GaN and MoS2, the as-grown multilayer MoS2-on-GaN film shows high material quality in terms of low full width at half-maximum (similar to 5.16 cm(-1)) for the E-2g(1) Raman mode and a high absorption coefficient (similar to 10(6) cm(-1)) in the wavelength range of 405-638 nm. Under a wavelength of 405 nm at an incident power of 2 mWand applied voltage of 9 V, the fabricated MoS2-on-GaN phototransistor achieved a maximum responsivity of 17.2 A/W, a photocurrent gain of 53.6, and an external quantum efficiency of 5289%, with specific detectivity (similar to 10(10)-10(12) Jones) and low noise equivalent power (10(-12)-10(-14) W/Hz(1/2)) in the visible range of 405-638 nm. A typical response time of 0.1-4 s in the ambient air has also been recorded for the demonstrated MoS2-on-GaN phototransistor. Our work paves a technologic stepping stone for MoS2-based phototransistors for multifunctional transparent and touch-based optoelectronics in the future. (C) 2019 Chinese Laser Press
Root Cause Analysis and Correction of Single Metal Contact Open-Induced Scan Chain Failure in 90nm node VLSI
(2017-01-01)
Ting, Chao-Cheng
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Liu, Ya-Chi
;
Chen, Hsuan-Hsien
;
Tsai, Chung-Ching
;
Shih, Liwen
In this paper, the localization of open metal contact for 90nm node SOC is reported based on Electron Beam Absorbed Current (EBAC) technique and scan diagnosis for the first time. According to the detected excess carbon, silicon and oxygen signals obtained from X-ray energy dispersive spectroscopy (EDX), the failure was deemed to be caused by the incomplete removal of silicate photoresist polymer formed during the O-2 plasma dry clean before copper plating. Based on this, we proposed to replace the dry clean with diluted HF clean prior to the copper plating, which can significantly remove the silicate polymers and increase the yield.
The development of low-temperature atomic layer deposition of HfO2 for TEM sample preparation on soft photo-resist substrate
(2018-01-01)
Peng, Kang-Ping
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Liu, Ya-Chi
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Lin, I-Feng
;
Lin, Chih-Chien
;
Huang, Shu-Wei
In this study, the method of low-temperature atomic layer deposition (ALD), which is applied on the soft photo-resist (PR) substrate forming hafnium dioxide (HfO2) at 40 degrees C to 85 degrees C, is reported for the first time. This reveals the potential application in the TEM sample preparation. The thickness, refractive index, band gap, and depth profiling chemical state of the thin film are analyzed by ellipsometry, X-ray diffraction, and photoelectron spectroscopy respectively. Our TEM image shows a clear boundary between the photo-resist and hafnium dioxide deposited on PR, which indicates the low-temperature atomic layer deposition (ALD) may lead a new way for TEM sample preparation in advanced technology node.
The size effect of titania-supported Pt nanoparticles on the electrocatalytic activity towards methanol oxidation reaction primarily via the bifunctional mechanism
(2015-04-15)
Ting, Chao-Cheng
;
Liu, Chung-Hsuan
;
Tai, Chun-Yen
;
Hsu, Shih-Chieh
;
Chao, Chih-Shuan
We prepared Pt nanoparticles of different particle sizes by plasma enhanced atomic layer deposition (PEALD) on the native oxide surface layer of Ti thin films, and investigated the Pt particle size effect on the electrocatalytic activity towards methanol oxidation reaction (MOR) in acidic media. The average Pt nanoparticles size ranges from 3 nm to 7 nm depending on the number of the PEALD reaction cycles. The electronic interaction between Pt nanoparticles and the TiO2 support is insignificant according to x-ray photoelectron spectroscopy analyses, suggesting that the influence of the Pt particle size on the electrocatalytic activity can be mainly described by the bifunctional mechanism. From cyclic voltammetry measurements, Pt particles of smaller size have a better CO tolerance in MOR. We proposed the reaction steps for the electrooxidation of CO adspecies on Pt nanoparticles on the basis of the bifunctional mechanism. The electrode with Pt nanoparticles of similar to 5 nm in size shows the best electrocatalytic performance in terms of CO tolerance and electrochemical stability. (C) 2015 Elsevier B.V. All rights reserved.