Browsing by Author "Wang, Shiang-Yu"

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Characteristics of surface plasmon coupled quantum well infrared photodetectors
(2017-06-28)
Hsu, Wei-Cheng
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Ling, Hong-Shi
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Wang, Shiang-Yu
;
Lee, Chien-Ping
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電機學院
Quantum Well Infrared Photodetectors (QWIPs) with different structures were characterized for the study of surface plasmon wave coupling. Detailed comparisons between surface plasmon coupled and etched grating coupled devices were investigated. A bias dependence for the enhancement of the responsivity of surface plasmon coupled devices was found, especially for the samples with non-uniform quantum wells. The non-uniform QWIPs with surface plasmon coupling showed an asymmetric enhancement with respect to the bias directions. Stronger enhancements were shown under the biases when a higher effective electric field region is close to the collector. The change of the photocarrier escape probability due to the narrow coupling bandwidth of the surface plasmon wave is attributed to this unexpected bias dependence. Published by AIP Publishing.
Dependence of Performance of Surface Plasmon Coupled Quantum Well Infrared Photodetectors on Doping
(2018-11-01)
Hsu, Wei-Cheng
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Ling, Hong-Shi
;
Wang, Shiang-Yu
;
Lee, Chien-Ping
;
電子工程學系及電子研究所
Three samples of Quantum Well Infrared Photodetectors (QWIPs) with different well doping were proposed for comparison between metallic grating and etched grating. All different doping samples with detectivity 1x10(11) cm*Hz(0.5)/W were achieved under 77 K with metallic grating and the highest detectivity was 2.92x10(11) cm*Hz(0.5)/W with 3.3E17 cm(-3) well doping. The metallic grating samples showed a different quantum efficiency (QE) increment behavior from the etched grating samples as we increased the well doping. The QE enhancement of metallic grating sample was smaller than that in positive bias due to the potential spike between the AlGaAs/GaAs interface. The metallic grating device is more sensitive to the extra barrier between the AlGaAs/GaAs interface because of a narrower coupling bandwidth of surface plasmon. Though the enhancement varied between different samples as we changed the well dopings, the detectivity could still be kept within a reasonable range, which is important for focal plane array applications.
GA BASED HYBRID FUZZY RULE OPTIMIZATION APPROACH FOR ELEVATOR GROUP CONTROL SYSTEM
(2013)
Chen, Ta-Cheng
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Hsu, Yuan-Yong
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Lee, An-Chen
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Wang, Shiang-Yu
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機械工程學系
Elevators are the essential transportation tools in high buildings so that elevator group control system (EGCS) is developed to dynamically layout the schedule of elevators in a group. In this study, a fuzzy rule based intelligent EGCS optimized by genetic algorithm has been proposed where the rules with the corresponding parameters are generated optimally so as to maximize service quality. The experimental results show that the performance of our approach is superior to these of traditional approaches in the literature.
High Transmittance and Broaden Bandwidth through the Morphology of Anti-Reflective Layers on THz Polarizer with Si Substrate
(2017-01-01)
Chi, Nai-Chen
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Yu, Ting-Yang
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Tsai, Hsin-Cheng
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Wang, Shiang-Yu
;
Luo, Chih-Wei
To improve the transmittance of THz component and overcome the difficulties of fragile structure as well as ensuring precise alignment of existing methods, a new method involving the mature 3DIC through-silicon via (TSV) technology has been proposed to make anti-reflection layer with suitable effective refractive index based on the robustness of Si wafer. Cu wire-grid polarizers were also fabricated on wafer. The THz polarizers were completed after wafer bonding with Cu sealing ring and In/Sn guard ring. Not only the new method is easier for production with better performance, but also the silicon substrate has several advantages. The novel method has proven that THz optical component could be constructed with a nearly 100% transmittance, or widened the transmittance spectrum range from 0.5 to 2 THz when transmittances is sacrificed to 70% instead of a near 100%. Furthermore, a robust structure could also be expected with broadband transmission and excellent extinction ratio. It is properly optimized for mass production because the fabrication method could be easily done and does not required high cost.
High Transmittance Broadband THz Polarizer Using 3D-IC Technologies
(2017-01-01)
Chi, Nai-Chen
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Yu, Ting-Yang
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Tsai, Hsin-Cheng
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Wang, Shiang-Yu
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Luo, Chih-Wei
A novel method of fabricating high transmittance and broadband terahertz (THz) polarizers is introduced with several advantages. A polarizer with an approximate 100% transmittance is demonstrated with single central frequency of anti-reflection (AR) layers between 0.5 THz and 2 THz. Broadband polarizer, which has a transmission spectrum of over 70% uniformity, is fabricated by bonding two wafers with different AR layers. The bandwidth of broadband THz polarizer exceeds 1 THz. Extinction ratio of the polarizer is about 30 dB depending on the frequency and Cu wire pitch. The high transmittance and broadband THz polarizer can be achieved through deep reactive-ion etching (DRIE) and wafer bonding. This new fabricating method of THz polarizers has advantages of lower cost, no accurate alignment requirement and robust structure. Therefore, this approach can possibly benefit the mass production of THz optical components in THz applications and even more.
High Transmittance Silicon Terahertz Polarizer Using Wafer Bonding Technology
(2015-01-01)
Yu, Ting-Yang
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Tsai, Hsin-Cheng
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Wang, Shiang-Yu
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Luo, Chih-Wei
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Chen, Kuan-Neng
Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive-ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150 degrees C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure andlow cost with no precision optical alignment required.
Long-Wavelength Quantum-Dot Infrared Photodetectors With Operating Temperature Over 200 K
(2009-01-01)
Ling, Hong-Shi
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Wang, Shiang-Yu
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Lee, Chien-Ping
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Lo, Ming-Cheng
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電子工程學系及電子研究所
We demonstrate the high-temperature operation of confinement enhanced dots-in-a-well (CE-DWELL) quantum-dot infrared photodetectors (QDIPs). The thin Al(0.3)Ga(0.7)As barrier layer added above the InAs QDs greatly improve the lateral confinement of QD states in the In(0.15)Ga(0.85)M DWELL structure and the device performance. With better device parameters of CE-DWELL, it is possible to achieve high quantum efficiency, high operating temperature, and long-wavelength detection at the same time.
Robust terahertz polarizers with high transmittance at selected frequencies through Si wafer bonding technologies
(2017-12-01)
Yu, Ting-Yang
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Chi, Nai-Chen
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Tsai, Hsin-Cheng
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Wang, Shiang-Yu
;
Luo, Chih-Wei
Terahertz (THz) polarizers with robust structure and high transmittance are demonstrated using 3D-integrated circuit (IC) technologies. A Cu wire-grid polarizer is sealed and well protected by Si-bonded wafers through a low-temperature eutectic bonding method. Deep reactive-ion etching is used to fabricate the anti-reflection (AR) layers on outward surfaces of bonded wafers. The extinction ratio and transmittance of polarizers are between 20 dB and 33 dB, and 13 dB and 27 dB for 10 mu m and 20 mu m pitch wire-grids, respectively, and 100% at central frequency, depending on frequency and AR layer thickness. The process of polarizer fabrication is simple from mature semiconductor manufacturing techniques that lead to high yield, low cost, and potential for THz applications. (C) 2017 Optical Society of America
Vertically Coupled Quantum-Dot Infrared Photodetectors
(2010-06-01)
Lo, Ming-Cheng
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Wang, Shiang-Yu
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Ling, Hong-Shi
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Lee, Chien-Ping
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電子工程學系及電子研究所
Vertically coupled InAs-GaAs quantum-dot infrared photodetectors (QDIPs) were studied in this letter. With vertically coupled quantum dots (QDs), the QDs in the same column share the same electronic states which remove the QD size variation effect in the growth direction and result in a narrow response band and higher peak quantum efficiency. The coupled states increase the capture probability and also facilitate the carrier flow among QD layers. The frequency response of vertically coupled QDIPs is much faster than that of the conventional ones.
Voltage-tunable dual-band quantum dot infrared photodetectors for temperature sensing
(2012-05-07)
Ling, Hong-Shi
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Wang, Shiang-Yu
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Hsu, Wei-Cheng
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Lee, Chien-Ping
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電子工程學系及電子研究所
We report voltage-tunable 3-5 mu m & 8-12 mu m dual-band detection in the InAs/Al0.3Ga0.7As/In0.15Ga0.85As confinement-enhanced dots-in-a-well quantum dot infrared photodetectors. The capability in temperature sensing is also demonstrated. Distinct response peaks at 5.0 mu m and 8.6 mu m were observed in the photocurrent spectra with working temperature up to 140K. The two peaks correspond to the transition paths from the quantum dot ground state to the quantum well state and the quantum dot excited state, respectively. At 77K, the response ratio of the 8.6 mu m peak over the 5.0 mu m peak changes from 0.29 at -3V to 5.8 at + 4.8V. Excellent selectivity between the two peaks with bias voltage makes the device attractive for third-generation imaging systems with pixel-level multicolor functionality. (C)2012 Optical Society of America
Wavelength tuning of surface plasmon coupled quantum well infrared photodetectors
(2018-01-08)
Hsu, Wei-Cheng
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Ling, Hong-Shi
;
Wang, Shiang-Yu
;
Lee, Chien-Ping
;
電機學院
A novel method of detection wavelength tuning for surface plasmon coupled quantum well infrared photodetectors (QWIPs) was demonstrated. By changing of the thickness of the top contact layer, the detection wavelength can be adjusted. The displacement of the detection wavelength is related to the effective dielectric constant of the dielectric layers in the device structure. The peak wavelength moves toward longer wavelength as the contact layer thickness decreases. With a proper match of the 2D metal hole array and the QW absorption region, the responsivity can be kept within a reasonable range for samples with different top contact layer thicknesses. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement