Browsing by Author "Li, Yi-Ming"

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A Diffusion Model to Growth Phase Forecasting of 3G Industry in Taiwan
(2008)
Lin, Chen-Chun
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Tang, Ying-Hwa
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Shyu, Joseph Z.
;
Li, Yi-Ming
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科技管理研究所
This study provides a system dynamics approach on the foundation of BASS diffusion model and constructing model upon the 3G adoption critical factor in the viewpoint of new product development. This thesis is to predict the future demand for 3G mobile for diffusion of innovation, whose model is often used to predict the demand for new products and discuss the dynamic process of diffusion. Accordingly, this study can provide better efficient advice to the industry of the up-coming 3G environment. This research adopts diffusion model, least squares analysis and logistic analysis to forecast the future demand. The data is taken from Telecommunications Carriers Association subscriber database in Taiwan in 2007. These analysis tools were MatLab, LogletLab and SPSS. Thus, the aims of present research are: to investigate this innovation diffusion; to identify adoption by potential adopters with potential non-adopters of the innovation. The methodology was tested, compared and results revealed that the prediction capability of the proposed system dynamics methodology access to ODE-EULER is better than those methodologies of LogletLab and least squares analysis.
Lateral amorphous selenium metal-insulator-semiconductor-insulator-metal photodetectors using ultrathin dielectric blocking layers for dark current suppression
(2016-12-21)
Chang, Cheng-Yi
;
Pan, Fu-Ming
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Lin, Jian-Siang
;
Yu, Tung-Yuan
;
Li, Yi-Ming
We fabricated amorphous selenium (a-Se) photodetectors with a lateral metal-insulator-semiconductor-insulator-metal (MISIM) device structure. Thermal aluminum oxide, plasma-enhanced chemical vapor deposited silicon nitride, and thermal atomic layer deposited (ALD) aluminum oxide and hafnium oxide (ALD-HfO2) were used as the electron and hole blocking layers of the MISIM photodetectors for dark current suppression. A reduction in the dark current by three orders of magnitude can be achieved at electric fields between 10 and 30 V/mu m. The effective dark current suppression is primarily ascribed to electric field lowering in the dielectric layers as a result of charge trapping in deep levels. Photogenerated carriers in the a-Se layer can be transported across the blocking layers to the Al electrodes via Fowler-Nordheim tunneling because a high electric field develops in the ultrathin dielectric layers under illumination. Since the a-Se MISIM photodetectors have a very low dark current without significant degradation in the photoresponse, the signal contrast is greatly improved. The MISIM photodetector with the ALD-HfO2 blocking layer has an optimal signal contrast more than 500 times the contrast of the photodetector without a blocking layer at 15 V/mu m. Published by AIP Publishing.
Optimization of physics-based equivalent circuits for microstrip patch antennas
(2007)
Chiu, Tang-Jung
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Kuo, Yi-Ting
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Chao, Hsueh-Yung (Robert)
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Li, Yi-Ming
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電信工程研究所
Photoconductive properties of polycrystalline selenium based lateral MISIM photodetectors of high quantum efficiency using different dielectrics as the charge blocking layer
(2019-07-01)
Chang, Cheng-Yi
;
Huang, Yu-Wei
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Lin, Yi-Jie
;
Liao, Jye-Yow
;
Lin, Jian-Siang
We studied the photoconductive performance of polycrystalline selenium (pc-Se) based photodetectors with a lateral metal-insulator-semiconductor-insulator-metal (MISIM) device structure. The insulator layer is a 10 nm-thick Ga2O3, HfO2, or Al2O3 thin film, and used as a charge blocking layer (CBL) to suppress dark current injected from the Al electrodes. The dark current suppression primarily depends on the barrier height of the junctions between the CBLs and electrodes. The Ga2O3 CBL exhibits a poor dark current suppression compared to the HfO2 and the Al2O3 CBLs because of a lower electron barrier at the cathode. The lateral pc-Se photodetectors exhibit a very high internal photocurrent gain due to Fowler-Nordheim tunneling at relatively low applied voltages. The better crystallinity of pc-Se grains formed on the Ga2O3 CBL leads to a higher photoconversion efficiency for the MISIM-Ga2O3 photodetector. Compared with amorphous Se based lateral MISIM photodetectors, the pc-Se photodetectors demonstrate a uniform and much better photoconductive performance over the visible spectrum.