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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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Author: search.filters.author.Lee, C. P.Subject: search.filters.subject.Intersubband

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    Spectral response and device performance tuning of long-wavelength InAs QDIPs
    (2011-05-01)
    Ling, H. S.
    ;
    Wang, S. Y.
    ;
    Lee, C. P.
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    Long-wavelength InAs QDIPs with different thicknesses of InGaAs cap layer in the confinement-enhanced dots-in-a-well (CE-DWELL) structure were investigated. The sample with 3 nm cap layer shows primarily single band detection at 7 mu m that stems from the transition between QD states, but the 5 nm and 7 nm samples reveal voltage-tunable dual band detection in the region of 6-11 mu m from transitions to the states in the dots as well as the states in the well. The wavefunction coupling of transition states is effectively modified by the change of cap-layer thickness and the bias polarity, which leads to the observed spectral change and demonstrates the flexibility of the CE-DWELL QDIPs. For higher peak quantum efficiency (QE), thin InGaAs cap layers are used to obtain focused absorption strength. With 3 nm cap layer in the CE-DWELL, a respectable QE of 7.23% is reached for 10-stack QDIPs with 7 mu m detection wavelength at 77K. and a high detectivity of 3.4 x 10(10) Jones is also obtained. (C) 2010 Elsevier B.V. All rights reserved.
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    Temperature dependence of quantum efficiency in Quantum Dot Infrared Photodetectors
    (2011-05-01)
    Wang, S. Y.
    ;
    Ling, H. S.
    ;
    Lee, C. P.
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    The behavior of quantum efficiency in QDIPs was studied in details with simple InAs/GaAs QDs and DWELL QDs structures. Despite of the large difference of the excited state energy between the two samples, the QE shows similar trends with temperature and bias voltage. The voltage to reach the QE plateau decreases with temperature and the maximum QE decreases with temperature. Considering the repulsive potential from the charge inside the QDs, the effective barrier height and thickness for the photoexcited carrier is much reduced and the QE variation with voltage follows the calculated tunneling probability. Furthermore, the multi-phonon interaction which leads to the relaxation of the excited carrier is shown to be important to the decrease of QE with temperature. The enhanced relaxation rate decreases the maximum QE value at higher temperature. (C) 2010 Elsevier B.V. All rights reserved.
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    Confinement-enhanced dots-in-a-well QDIPs with operating temperature over 200 K
    (2009-11-01)
    Ling, H. S.
    ;
    Wang, S. Y.
    ;
    Lee, C. P.
    ;
    Lo, M. C.
    ;
    電子工程學系及電子研究所
    LWIR InAs/Al(0.3)Ga(0.7)As/In(0.15)Ga(0.85)As confinement-enhanced DWELL (CE-DWELL) QDIPs with operation temperatures higher than 200 K are reported. A thin Al(0.3)Ga(0.7)As barrier layer was inserted above the InAs QDs to improve the confinement of QD states in the In(0.15)Ga(0.85)As DWELL structure and the device performance. The better confinement of the electronic states increases the oscillator strength of the infrared absorption. The higher excited state energy also improves the escape probability of the photoelectrons. Compared with the conventional DWELL QDIPs, the quantum efficiency increases for more than 20 times and the detectivity is an order of magnitude higher at 77 K. 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. (C) 2009 Elsevier B.V. All rights reserved.
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    Detection wavelength and device performance tuning of InAs QDIPs with thin AlGaAs layers
    (2009-11-01)
    Wang, S. Y.
    ;
    Ling, H. S.
    ;
    Lo, M. C.
    ;
    Lee, C. P.
    ;
    電子工程學系及電子研究所
    QDIPs with thin inserted AlGaAs layers adjacent to the QDs were investigated for the tailoring of detection wavelength and device performance. Simple InAs/GaAs QDIPs and DWELL QDIPs with different insertion layer structure were studied. The thin AlGaAs layer is shown to effectively modify the electron wavefunction and associated confined state energies which lead to the change of the detection wavelength and the polarization dependent quantum efficiency. Furthermore. the dark current and gain also change with different device structures. The insertion of AlGaAs layers provides an additional freedom of tuning the electronics states involved in the infrared detection and also enables the improvement of the absorption and device performance. (C) 2009 Elsevier B.V. All rights reserved.