| Record 1 of 14 |
| Author(s): Li, L (Li, Lei); Cao, F (Cao, Feng); Wang, YD (Wang, Yiding); Cong, ML (Cong, Menglong); Li, L (Li, Li); An, YP (An, Yupeng); Song, ZY (Song, Zhenyu); Guo, SX (Guo, Shuxu); Liu, FQ (Liu, Fengqi); Wang, LJ (Wang, Lijun) |
| Title: Design and characteristics of quantum cascade laser-based CO detection system |
| Source: SENSORS AND ACTUATORS B-CHEMICAL, 142 (1): 33-38 OCT 12 2009 |
| Abstract: The authors report the design and characteristics of a mid-infrared quantum cascade laser-based CO detection system using the absorption in the P (14) line, at 2086.32 cm(-1). Measurements are performed through line scanning and signal processing to give sensitivities down to 2 ppm with the response time of 7 s. (c) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0925-4005 |
| DOI: 10.1016/j.snb.2009.08.025 |
| Record 2 of 14 |
| Author(s): Xu, PF (Xu, Peng-Fei); Yang, T (Yang, Tao); Ji, HM (Ji, Hai-Ming); Cao, YL (Cao, Yu-Lian); Gu, YX (Gu, Yong-Xian); Liu, Y (Liu, Yu); Ma, WQ (Ma, Wen-Quan); Wang, ZG (Wang, Zhan-Guo) |
| Title: Temperature-dependent modulation characteristics for 1.3 mu m InAs/GaAs quantum dot lasers |
| Source: JOURNAL OF APPLIED PHYSICS, 107 (1): Art. No. 013102 JAN 1 2010 |
| Abstract: Temperature-dependent modulation characteristics of 1.3 mu m InAs/GaAs quantum dot (QD) lasers under small signals have been carefully studied at various bias currents. Based on experimental observations, it is found that the modulation bandwidth significantly increases when excited state (ES) lasing emerges at high temperature. This is attributed to additional photons emitted by ES lasing which contribute to the modulation response. A rate equation model including two discrete electron energy levels and the level of wetting layer has been used to investigate the temperature-dependent dynamic behavior of the QD lasers. Numerical investigations confirm that the significant jump for the small signal modulation response is indeed caused by ES photons. Furthermore, we identify how the electron occupation probabilities of the two discrete energy levels can influence the photon density of different states and finally the modulation rate. Both experiments and numerical analysis show that the modulation bandwidth of QD lasers at high temperature can be increased by injecting more carriers into the ES that has larger electron state degeneracy and faster carrier's relaxation time than the ground state. |
| ISSN: 0021-8979 |
| Article Number: 013102 |
| DOI: 10.1063/1.3277042 |
| Record 3 of 14 |
| Author(s): Meng, XQ (Meng, X. Q.); Peng, HW (Peng, Haowei); Gai, YQ (Gai, Y. Q.); Li, JB (Li, Jingbo) |
| Title: Influence of ZnS and MgO Shell on the Photoluminescence Properties of ZnO Core/Shell Nanowires |
| Source: JOURNAL OF PHYSICAL CHEMISTRY C, 114 (3): 1467-1471 JAN 28 2010 |
| Abstract: By sequential growth of the core and shell of different materials, ZnO/ZnS and ZnO/MgO core/shell nanowire arrays are fabricated. Photoluminescence properties of these samples with different shell thicknesses are studied in detail. The results indicate that the ZnS shell thickness as a function of treatment time will noticeably change the photoluminescence intensity of the ZnO nanowires, whereas the MgO shell will not change the photoluminescence intensity any more after it saturates the surface dangling bonds of ZnO core. Large-scale first-principles calculations indicate that, unlike the ZnO/MgO core/shell nanowires, the electrons and holes of which are both confined in the core of the nanowires (type-I heterostructures), the ZnO/ZnS core/shell nanowires are type-II heterostructures, the electrons and holes of which are respectively confined in the core and the shell; as a result, the separation of electrons and holes in the ZnO/ZnS core/shell nanowires will reduce the spatial overlap between them, leading to the decrease of the photoluminescence intensity in this system. The experimental observations are in good agreement with first-principles calculations |
| ISSN: 1932-7447 |
| DOI: 10.1021/jp909176p |
| Record 4 of 14 |
| Author(s): Xiong, B (Xiong Bo); Zhang, SB (Zhang Shu-Bao); Guo, L (Guo Lin); Zhang, L (Zhang Ling); Lin, XC (Lin Xue-Chun); Li, JM (Li Jin-Min) |
| Title: Period Continuous Tuning of an Efficient Mid-Infrared Optical Parametric Oscillator Based on a Fan-out Periodically Poled MgO-Doped Lithium Niobate |
| Source: CHINESE PHYSICS LETTERS, 27 (1): Art. No. 014206 JAN 2010 |
| Abstract: We report a period continuously tunable, efficient, mid-infrared optical parametric oscillator (OPO) based on a fan-out periodically poled MgO-doped congruent lithium niobate (PPMgLN). The OPO is pumped by a Nd:YAG laser and a maximum idler output average power of 1.65 W at 3.93 mu m is obtained with a pump average power of 10.5 W, corresponding to the conversion efficiency of about 16% from the pump to the idler. The output spectral properties of the OPO with the fan-out crystal are analyzed. The OPO is continuously tuned over 3.78-4.58 mu m (idler) when fan-out periods are changed from 27.0 to 29.4 mu m. Compared with temperature tuning, fan-out period continuous tuning has faster tuning rate and wider tuning range. |
| ISSN: 0256-307X |
| Article Number: 014206 |
| DOI: 10.1088/0256-307X/27/1/014206 |
| Record 5 of 14 |
| Author(s): Wang, SJ (Wang Shi-Jiang); Huang, YZ (Huang Yong-Zhen); Yang, YD (Yang Yue-De); Hu, YH (Hu Yong-Hong); Xiao, JL (Xiao Jin-Long); Du, Y (Du Yun) |
| Title: Output Characteristics of an InP/InGaAsP Triangle Microcavity Laser |
| Source: CHINESE PHYSICS LETTERS, 27 (1): Art. No. 014213 JAN 2010 |
| Abstract: Mode competitions between modes with different output coupling efficiencies can result in optical bistability under certain asymmetric nonlinear gain. For a GaInAsP/InP equilateral triangle microlaser with the side length of 10 mu m, the drop of the output power with the increase of the injection current is observed corresponding to transverse mode transitions. Furthermore, the measured laser spectra up to 270 K show that lasing modes coexist with the wavelength interval of 39 nm at 240 K. The emission at 5.2 THz can be expected by the mode frequency beating with the 39 nm interval. |
| ISSN: 0256-307X |
| Article Number: 014213 |
| DOI: 10.1088/0256-307X/27/1/014213 |
| Record 6 of 14 |
| Author(s): Zhu, Y (Zhu Yu); Xu, XJ (Xu Xue-Jun); Li, ZY (Li Zhi-Yong); Zhou, L (Zhou Liang); Han, WH (Han Wei-Hua); Fan, ZC (Fan Zhong-Chao); Yu, YD (Yu Yu-De); Yu, JZ (Yu Jin-Zhong) |
| Title: High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre |
| Source: CHINESE PHYSICS B, 19 (1): Art. No. 014219 JAN 2010 |
| Abstract: A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46% and 25% at a wavelength of 1.55 mu m are achieved by simulation and experiment, respectively. An optical 3 dB bandwidth of 45 nm from 1530 nm to 1575 nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10 nm in etch depth is achievable. The measurement results indicate that the alignment error of +/-2 mu m results in less than 1 dB additional coupling loss. |
| ISSN: 1674-1056 |
| Article Number: 014219 |
| Record 7 of 14 |
| Author(s): Wang, LJ (Wang Liang-Ji); Zhang, SM (Zhang Shu-Ming); Zhu, JH (Zhu Ji-Hong); Zhu, JJ (Zhu Jian-Jun); Zhao, DG (Zhao De-Gang); Liu, ZS (Liu Zong-Shun); Jiang, DS (Jiang De-Sheng); Wang, YT (Wang Yu-Tian); Yang, H (Yang Hui) |
| Title: Effect of surface treatment of GaN based light emitting diode wafers on the leakage current of light emitting diode devices |
| Source: CHINESE PHYSICS B, 19 (1): Art. No. 017307 JAN 2010 |
| Abstract: To form low-resistance Ohmic contact to p-type GaN, InGaN/GaN multiple quantum well light emitting diode wafers are treated with boiled aqua regia prior to Ni/Au (5 nm/5 nm) film deposition. The surface morphology of wafers and the current-voltage characteristics of fabricated light emitting diode devices are investigated. It is shown that surface treatment with boiled aqua regia could effectively remove oxide from the surface of the p-GaN layer, and reveal defect-pits whose density is almost the same as the screw dislocation density estimated by x-ray rocking curve measurement. It suggests that the metal atoms of the Ni/Au transparent electrode of light emitting diode devices may diffuse into the p-GaN layer along threading dislocation lines and form additional leakage current channels. Therefore, the surface treatment time with boiled aqua regia should not be too long so as to avoid the increase of threading dislocation-induced leakage current and the degradation of electrical properties of light emitting diodes. |
| ISSN: 1674-1056 |
| Article Number: 017307 |
| Record 8 of 14 |
| Author(s): Lu, XQ (Lue Xue-Qin); Jin, P (Jin Peng); Wang, ZG (Wang Zhan-Guo) |
| Title: A broadband external cavity tunable InAs/GaAs quantum dot laser by utilizing only the ground state emission |
| Source: CHINESE PHYSICS B, 19 (1): Art. No. 018104 JAN 2010 |
| Abstract: A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm(2) only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current density can be reduced remarkably compared with the free-running QD gain device. |
| ISSN: 1674-1056 |
| Article Number: 018104 |
| Record 9 of 14 |
| Author(s): Zheng, GL (Zheng, Gaolin); Yang, AL (Yang, Anli); Wei, HY (Wei, Hongyuan); Liu, XL (Liu, Xianglin); Song, HP (Song, Huaping); Guo, Y (Guo, Yan); Jia, CH (Jia, Caihong); Jiao, CM (Jiao, Chunmei); Yang, SY (Yang, Shaoyan); Zhu, QS (Zhu, Qinsheng); Wang, ZG (Wang, Zhanguo) |
| Title: Effects of annealing treatment on the formation of CO2 in ZnO thin films grown by metal-organic chemical vapor deposition |
| Source: APPLIED SURFACE SCIENCE, 256 (8): 2606-2610 FEB 1 2010 |
| Abstract: Post-growth annealing was carried out on ZnO thin films grown by metal-organic chemical vapor deposition (MOCVD). The grain size of ZnO thin film increases monotonically with annealing temperature. The ZnO thin films were preferential to c-axis oriented after annealing as confirmed by Xray diffraction (XRD) measurements. Fourier transformation infrared transmission measurements showed that ZnO films grown at low temperature contains CO2 molecules after post-growth annealing. A two-step reaction process has been proposed to explain the formation mechanism of CO2, which indicates the possible chemical reaction processes during the metal-organic chemical vapor deposition of ZnO films. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0169-4332 |
| DOI: 10.1016/j.apsusc.2009.10.109 |
| Record 10 of 14 |
| Author(s): Zhang, WC (Zhang, Wan-cheng); Wu, NJ (Wu, Nan-jian); Hashizume, T (Hashizume, Tamotsu); Kasai, S (Kasai, Seiya) |
| Book Group Author(s): IEEE |
| Title: Multiple-valued Logic Gates using Asymmetric Single-electron Transistors |
| Source: ISMVL: 2009 39TH IEEE INTERNATIONAL SYMPOSIUM ON MULTIPLE-VALUED LOGIC: 337-342 2009 |
| Conference Title: 39th IEEE International Symposium on Multiple-Valued Logic |
| Conference Date: MAY 21-23, 2009 |
| Conference Location: Naha, JAPAN |
| Abstract: This paper proposes novel multiple-valued (MV) logic gates by using asymmetric single-electron transistors (SETs). Asymmetric single-electron transistors have two tunneling junctions with largely different resistances and capacitances. We fully exploited the Unique Coulomb staircase characteristic of asymmetric SETs to compactly, finish logic operations. We build MV literal gates with wide range Of radixes by using a pair of asymmetric SETs. We showed that, arbitrary radix-4 literal gate can be realized using a pair of asymmetric SETs. We also proposed AN analog-digital conversion circuits. The MV logic gates have very compact structures and low power dissipation. |
| ISBN: 978-1-4244-3841-9 |
| Record 11 of 14 |
| Author(s): Yang, W (Yang Wei); Ji, Y (Ji Yang); Luo, HH (Luo Hai-Hui); Ruan, XZ (Ruan Xue-Zhong); Wang, WZ (Wang Wei-Zhu); Zhao, JH (Zhao Jian-Hua) |
| Title: Electronic noise of diluted magnetic semiconductor (Ga,Mn)As around Curie point |
| Source: ACTA PHYSICA SINICA, 58 (12): 8560-8565 DEC 2009 |
| Abstract: We have studied the spontaneous fluctuation noise spectrum of (Ga,Mn)As in frequency domian from 1 kHz to 250 kHz. We found that the electronic noise. can be reduced by a magnetic field and its magnitude increases with increasing temperature of the (Ga,Mn)As sample. The electrical noise spectra at different frequencies have different temperature dependence and their amplitude changes at the phase transition temperature, suggesting that the phase transition process of (Ga,Mn)As is subtly different from normal magnetic materials. Our results may help understanding the origin of magnetism in (Ga,Mn)As. |
| ISSN: 1000-3290 |
| Record 12 of 14 |
| Author(s): Lu, QY (Lu, Quan-Yong); Zhang, W (Zhang, Wei); Wang, LJ (Wang, Li-Jun); Gao, Y (Gao, Yu); Yin, W (Yin, Wen); Zhang, QD (Zhang, Quan-De); Liu, WF (Liu, Wan-Feng); Liu, FQ (Liu, Feng-Qi); Wang, ZG (Wang, Zhan-Guo) |
| Title: Design of Low-Loss Surface-Plasmon Quantum Cascade Lasers |
| Source: JAPANESE JOURNAL OF APPLIED PHYSICS, 48 (12): Art. No. 122101 DEC 2009 |
| Abstract: A low-loss waveguide design for the mid-infrared surface-plasmon quantum cascade lasers (QCLs) is proposed. A waveguide loss of 6.5-8 cm(-1) with a confinement factor above 50% is obtained by modulating the doping concentration and thickness of the In0.53Ga0.47As (InGaAs) contact layer to around 1.3 x 10(19)cm(-3) and 100 nm. The overlapping of lasing mode with the highly lossy surface plasmons is therefore substantially reduced. The delocalizing the lasing mode profile to the substrate improves the far field angle of the lasing beam in the epilayer direction with a reduction about 25 degrees. (C) 2009 The Japan Society of Applied Physics |
| ISSN: 0021-4922 |
| Article Number: 122101 |
| DOI: 10.1143/JJAP.48.122101 |
| Record 13 of 14 |
| Author(s): Ma, WL (Ma, Wenlong); Shi, Y (Shi, Yin); Zhang, YH (Zhang, Yaohui); Wu, ZY (Wu, Zhenyan) |
| Book Group Author(s): IEEE |
| Title: High Speed Snap-shot Mode Readout circuit for QWIP IR FPAs |
| Source: ICIEA: 2009 4TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS, VOLS 1-6: 1003-1006 2009 |
| Conference Title: 4th IEEE Conference on Industrial Electronics and Applications |
| Conference Date: MAY 25-27, 2009 |
| Conference Location: Xian, PEOPLES R CHINA |
| Abstract: The design and fabrication of a Snap-shot mode high speed ROIC for GaAs/AlGaAs QWIP FPAs was reported. The snap-shot CTIA input stage with pixel-level skimming increased the readout speed and integrated voltage swing. The column-shared CDS circuits improved the noise and speed performance under low power dissipation. The multiplexed sampling voltage is buffered to output with high speed output buffer amplifier. The experimental ROIC chip of 128 X 128 array is fabricated using 0.35um CMOS mixed signal process. The chip has charge capacity of 2.57 X 10(6) electrons and transimpedance of 1 X 10(8)Omega. The measurements show that the readout speed is 10Mbps, the maximum frame rate is 640 frame/s for 128 X 128 FPAs under the 3.3V supply voltage. |
| ISBN: 978-1-4244-2799-4 |
| Record 14 of 14 |
| Author(s): Han, XB (Han, Xiaobing); Kou, LZ (Kou, Liangzhi); Lang, XL (Lang, Xiaoli); Xia, JB (Xia, Jianbai); Wang, N (Wang, Ning); Qin, R (Qin, Rui); Lu, J (Lu, Jing); Xu, J (Xu, Jun); Liao, ZM (Liao, Zhimin); Zhang, XZ (Zhang, Xinzheng); Shan, XD (Shan, Xudong); Song, XF (Song, Xuefeng); Gao, JY (Gao, Jingyun); Guo, WL (Guo, Wanlin); Yu, DP (Yu, Dapeng) |
| Title: Electronic and Mechanical Coupling in Bent ZnO Nanowires |
| Source: ADVANCED MATERIALS, 21 (48): 4937-+ DEC 28 2009 |
| Abstract: A red shift of the exciton of ZnO nanowires is efficiently produced by bending strain, as demonstrated by a low-temperature (81 K) cathodoluminescence (CL) study of ZnO nanowires bent into L- or S-shapes. The figure shows a nanowire (Fig. a) with the positions of CL measurements marked. The corresponding CL spectra-revealing a peak shift and broadening in the region of the bend-are shown in Figure b. |
| ISSN: 0935-9648 |
| DOI: 10.1002/adma.200900956 |
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