Browsing by Author "Chen, Po-Chou"

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Color separation system with angularly positioned light source module for pixelized backlighting
(2010-01-18)
Chen, Po-Chou
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Lin, Hui-Hsiung
;
Chen, Cheng-Huan
;
Lee, Chi-Hung
;
Lu, Mao-Hong
A color-separation system that angularly positions color LEDs to produce color separation and a lens array to focus this light onto the pixels is proposed. The LED rays from different incident angles are mapped into corresponding sub-pixel positions to efficiently display color image, which can be used to replace the absorbing color filter in the conventional liquid crystal layer. In this paper, the prototype backlight has been designed, fabricated and characterized. The measurement results of this module showed that a gain factor of transmission efficiency three times more than that of conventional color filters efficiency improvement and a larger color gamut are expected. (C)2010 Optical Society of America
InAlAs/InGaAs metamorphic high electron mobility transistor with Cu/Pt/Ti gate and Cu airbridges
(2007-05-01)
Chang, Chun-Wei
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Chen, Po-Chou
;
Lee, Huang-Ming
;
Chen, Szu-Hung
;
Sahoo, Kartik Chandra
The use of a Cu/Pt/Ti Schottky contact structure and Cu-based airbridges for high-frequency metamorphic high electron mobility transistor (MHEMT) is successfully developed. The material characteristics of the Cu/Pt/Ti Schottky contact on i-InAlAs were studied. Judging from the results of the X-ray diffraction analysis, Auger electron spectroscopy, and transmission electron microscopy, the Cu/Pt/Ti Schottky contact structure on InAlAs was very stable after annealing at 350 degrees C. However, after 400 degrees C annealing, the reaction of copper with the layers underneath started to occur and formed the Cu4Ti phase. The Cu-metallized MHEMT using the proposed Cu/Pt/Ti T-gate structure and Cu-based airbridges has a saturated drain current of 673 mA/mm and a maximum transconductance of 750 mS/mm. The gate to drain breakdown voltage measured was 14.5 V at a gate reverse current of -1 mA/mm. The device also demonstrated a cutoff frequency F-t of 90 GHz and a maximum frequency of oscillation F-max of 165 GHz. An MHEMT with a Au/Pt/Ti gate was fabricated and compared with an MHEMT fabricated with the proposed Cu/Pt/Ti gate. These two kinds of MHEMTs showed similar F-t and F-max. These results demonstrate that the Cu/Pt/Ti T-gate and Cu-based airbridges can be used for MHEMT fabrication with excellent electrical characteristics.
The Imaging Behavior of an MRI Contrast Agent [Gd(TTDA-BOM)](2-) in a Mice Liver Tumor Model at 3 Tesla
(2010)
Jao, Jo-Chi
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Lu, Hsiang-Chin
;
Lu, Hsin-Ying
;
Wang, Yun-Ming
;
Liu, Gin-Chung
[Gd(TTDA-BOM)](2-) is a newly developed paramagnetic contrast agent. The aim of this study was to investigate the magnetic resonance imaging (MRI) behavior of [Gd(TTDA-BOM)](2-) in mice with implanted AS-30D (Chang hepatoma ascites, CHA) tumor in liver at a 3T high-field whole-body magnetic resonance (MR) scanner. The high-field MR scanner is expected to have a higher signal-to-noise ratio (SNR). The dynamic MRI studies show that the signal enhancement in liver is larger than that in tumor, so that the contrast-to-noise ratio (CNR) between liver and tumor increases after [Gd(TTDA-BOM)](2-) injection. During one-hour investigation, it was found that [Gd(TTDA-BOM)](2-) could stay in liver up to one hour. On the contrary, [Gd(DTPA)](2-) , a kind of commercial contrast agent, was excreted from liver quickly. Therefore, the CNR between liver and tumor using [Gd(TTDA-BOM)](2-) is larger than that using [Gd(DTPA)](2-) and remains high at least up to one hour. In conclusion, [Gd(TTDA-BOM)](2-) might have good potential for being a hepatobiliary MR contrast agent.
Thermal stability of Ti/Pt/Cu Schottky contact on InAlAs layer
(2006-08-21)
Lien, Yi-Chung
;
Chang, Edward Yi
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Chen, Szu-Hung
;
Chu, Li-Hsin
;
Chen, Po-Chou
Electrical characteristics and thermal stability of the Ti/Pt/Cu Schottky contact on InAlAs were investigated. The Ti/Pt/Cu Schottky contact had comparable electrical properties compared to the conventional Ti/Pt/Au contact after annealing. As judged from the material analysis, the Ti/Pt/Cu on InAlAs after 350 degrees C annealing showed no diffusion sign into the InAlAs. After 400 degrees C annealing, the interfacial mixing of Cu and the underlying layers occurred and resulted in the formation of Cu4Ti. The results show that Ti/Pt/Cu Schottky contact using platinum as the diffusion barrier is very stable up to 350 degrees C annealing and can be used for InAlAs/InGaAs high-electron mobility transistors and monolithic microwave integrated circuits. (c) 2006 American Institute of Physics.