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| Record 1 of 29 |
| Author(s): Wang, Y (Wang, Y.); Chen, NF (Chen, N. F.); Zhang, XW (Zhang, X. W.); Huang, TM (Huang, T. M.); Yin, ZG (Yin, Z. G.); Wang, YS (Wang, Y. S.); Zhang, H (Zhang, H.) |
| Title: Evaluation of thermal radiation dependent performance of GaSb thermophotovoltaic cell based on an analytical absorption coefficient model |
| Source: SOLAR ENERGY MATERIALS AND SOLAR CELLS, 94 (10): 1704-1710 OCT 2010 |
| Abstract: Applying the model dielectric function method, we have expressed the absorption coefficient of GaSb analytically at room temperature relating to the contribution of various critical points of its electronic band structure. The calculated absorption spectrum shows good agreement with the reported experimental data obtained by spectral ellipsometry on nominally undoped sample. Based on this analytical absorption spectrum, we have qualitatively evaluated the response of active absorbing layer structure and its photoelectric conversion properties of GaSb thermophotovoltaic device on the perturbation of external thermal radiation induced by the varying radiator temperature or emissivity. Our calculation has demonstrated that desirable thickness to achieve the maximum conversion efficiency should be decreased with the increment of radiator temperature and the performance degradation brought by any structure deviation from its optimal one would be stronger meanwhile. For the popular radiator temperature, no more than 1500 K in a real solar thermophotovoltaic system, and typical doping profile in GaSb cell, a reasonable absorbing layer structure parameter should be controlled within 100-300 nm for the emitter while 3000-5000 nm for the base. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0927-0248 |
| DOI: 10.1016/j.solmat.2010.05.032 |
| Record 2 of 29 |
| Author(s): Wang, ZG (Wang, Zhigang); Fu, ZG (Fu, Zhen-Guo); Wang, SX (Wang, Shuang-Xi); Zhang, P (Zhang, Ping) |
| Title: Magnetic quantum oscillations for the surface states of topological insulator Bi2Se3 |
| Source: PHYSICAL REVIEW B, 82 (8): Art. No. 085429 AUG 19 2010 |
| Abstract: We study quantum oscillations of the magnetization in Bi2Se3 (111) surface system in the presence of a perpendicular magnetic field. The combined spin-chiral Dirac cone and Landau quantization produce profound effects on the magnetization properties that are fundamentally different from those in the conventional semiconductor two-dimensional electron gas. In particular, we show that the oscillating center in the magnetization chooses to pick up positive or negative values depending on whether the zero-mode Landau level is occupied or empty. An intuitive analysis of these features is given and the subsequent effects on the magnetic susceptibility and Hall conductance are also discussed. |
| ISSN: 1098-0121 |
| Article Number: 085429 |
| DOI: 10.1103/PhysRevB.82.085429 |
| Record 3 of 29 |
| Author(s): Jiang, F (Jiang, Fang); Cai, LE (Cai, Li-E); Zhang, JY (Zhang, Jiang-Yong); Zhang, BP (Zhang, Bao-Ping) |
| Title: Formation of high reflective Ni/Ag/Ti/Au contact on p-GaN |
| Source: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 42 (9): 2420-2423 JUL 2010 |
| Abstract: A metallization scheme of Ni/Ag/Ti/Au has been developed for obtaining high reflective contacts on p-type GaN. In order to find optimal conditions to get a high reflectivity, we studied samples with various Ni thicknesses, annealing temperatures and annealing times. By annealing at 500 degrees C for 5 min in an O-2 ambient, a reflectivity as high as 94% was obtained from Ni/Ag/Ti/Au (1/120/120/50 nm). The effects of Ti layers on the suppression of Ag agglomeration were investigated by using Auger electron spectroscopy (AES). From AES depth profiles, it is clear that Ti acts as a diffusion barrier to prevent Au atoms from diffusing into the Ag layer, which is important in the formation of high reflectivity. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved. |
| ISSN: 1386-9477 |
| DOI: 10.1016/j.physe.2010.05.027 |
| Record 4 of 29 |
| Author(s): Zhou, XL (Zhou, X. L.); Chen, YH (Chen, Y. H.); Liu, JQ (Liu, J. Q.); Xu, B (Xu, B.); Ye, XL (Ye, X. L.); Wang, ZG (Wang, Z. G.) |
| Title: Abnormal temperature dependent photoluminescence of self-assembled InAs/GaAs surface quantum dots with high areal density |
| Source: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 42 (9): 2455-2459 JUL 2010 |
| Abstract: We have investigated temperature dependent photoluminescence of both buried and surface self-assembled InAs/GaAs quantum dots with an areal density up to similar to 10(11)/cm(2). Different from the buried quantum dots, the peak energy of surface quantum dots shows a blueshift relative to the bulk material variation from 15 to 130K. Besides the line width and the integrated intensity both first decrease and then increase in this temperature interval. The observed phenomena can be explained by carrier trapping effects by some shallow localized centers near the surface quantum dots. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 1386-9477 |
| DOI: 10.1016/j.physe.2010.06.008 |
| Record 5 of 29 |
| Author(s): Chen, L (Chen, L.); Yan, S (Yan, S.); Xu, PF (Xu, P. F.); Lu, J (Lu, J.); Deng, JJ (Deng, J. J.); Ji, Y (Ji, Y.); Wang, KY (Wang, K. Y.); Zhao, JH (Zhao, J. H.) |
| Title: Easy axis reorientation and magneto-crystalline anisotropic resistance of tensile strained (Ga,Mn)As films |
| Source: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 322 (21): 3250-3254 NOV 2010 |
| Abstract: We present a study of magnetic anisotropy by using magneto-transport and direct magnetization measurements on tensile strained (Ga,Mn)As films. The magnetic easy axis of the films is in-plane at low temperatures, while the easy axis flips to out-of-plane when temperature is raised or hole concentration is increased. This easy axis reorientation is explained qualitatively in a simple physical picture by Zeners pd model. In addition, the magneto-crystalline anisotropic resistance was also investigated experimentally and theoretically based on the single magnetic domain model. The dependence of sheet resistance on the angle between the magnetic field and [1 0 0] direction was measured. It is found that the magnetization vector M in the single-domain state deviates from the external magnetic field H direction at low magnetic field, while for high magnetic field, M continuously moves following the field direction, which leads to different resistivity function behaviors. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0304-8853 |
| DOI: 10.1016/j.jmmm.2010.06.002 |
| Record 6 of 29 |
| Author(s): Wang, KY (Wang, K. Y.); Edmonds, KW (Edmonds, K. W.); Irvine, AC (Irvine, A. C.); Wunderlich, J (Wunderlich, J.); Olejnik, K (Olejnik, K.); Rushforth, AW (Rushforth, A. W.); Campion, RP (Campion, R. P.); Williams, DA (Williams, D. A.); Foxon, CT (Foxon, C. T.); Gallagher, BL (Gallagher, B. L.) |
| Title: Domain wall resistance in perpendicular (Ga,Mn) As: Dependence on pinning |
| Source: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 322 (21): 3481-3484 NOV 2010 |
| Abstract: We have investigated the domain wall resistance for two types of domain walls in a (Ga,Mn)As Hall bar with perpendicular magnetization. A sizeable positive intrinsic DWR is inferred for domain walls that are pinned at an etching step, which is quite consistent with earlier observations. However, much lower intrinsic domain wall resistance is obtained when domain walls are formed by pinning lines in unetched material. This indicates that the spin transport across a domain wall is strongly influenced by the nature of the pinning. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0304-8853 |
| DOI: 10.1016/j.jmmm.2010.06.049 |
| Record 7 of 29 |
| Author(s): Liu, Y (Liu, Yu); Chen, YH (Chen, Yonghai); Wang, ZG (Wang, Zhanguo) |
| Title: Photoexcited charge current for the presence of pure spin current |
| Source: APPLIED PHYSICS LETTERS, 96 (26): Art. No. 262108 JUN 28 2010 |
| Abstract: The asymmetric spin distribution in k space caused by the pure spin current (PSC) can introduce a photoexcited charge current (PECC). This provides us a practical scheme for direct detection of PSC. We demonstrate theoretically that the PECC related to the PSC depends sensitively on the wave vector and spin orientation of the carriers, more important, the helicity dependence of this PECC provides us a way to refine it from the helicity independent background current by tuning the polarized laser beams from left to right circular polarization. (C) 2010 American Institute of Physics. [doi:10.1063/1.3455887] |
| ISSN: 0003-6951 |
| Article Number: 262108 |
| DOI: 10.1063/1.3455887 |
| Record 8 of 29 |
| Author(s): Zhang, Q (Zhang, Q.); Wang, XQ (Wang, X. Q.); Yin, CM (Yin, C. M.); Xu, FJ (Xu, F. J.); Tang, N (Tang, N.); Shen, B (Shen, B.); Chen, YH (Chen, Y. H.); Chang, K (Chang, K.); Ge, WK (Ge, W. K.); Ishitani, Y (Ishitani, Y.); Yoshikawa, A (Yoshikawa, A.) |
| Title: Strong circular photogalvanic effect in ZnO epitaxial films |
| Source: APPLIED PHYSICS LETTERS, 97 (4): Art. No. 041907 JUL 26 2010 |
| Abstract: We report a strong circular photogalvanic effect (CPGE) in ZnO epitaxial films under interband excitation. It is observed that CPGE current is as large as 100 nA/W in ZnO, which is about one order in magnitude higher than that in InN film while the CPGE currents in GaN films are not detectable. The possible reasons for the above observations are the strong spin orbit coupling in ZnO or the inversed valence band structure of ZnO. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467835] |
| ISSN: 0003-6951 |
| Article Number: 041907 |
| DOI: 10.1063/1.3467835 |
| Record 9 of 29 |
| Author(s): Xu, PF (Xu, P. F.); Nie, SH (Nie, S. H.); Meng, KK (Meng, K. K.); Wang, SL (Wang, S. L.); Chen, L (Chen, L.); Zhao, JH (Zhao, J. H.) |
| Title: Co doping enhanced giant magnetocaloric effect in Mn1-xCoxAs films epitaxied on GaAs (001) |
| Source: APPLIED PHYSICS LETTERS, 97 (4): Art. No. 042502 JUL 26 2010 |
| Abstract: A giant magnetocaloric effect was found in series of Mn1-xCoxAs films epitaxied on GaAs (001). The maximum magnetic entropy change caused by a magnetic field of 4 T is as large as 25 J/kg K around room temperature, which is about twice the value of pure MnAs film. The observed small thermal hysteresis is more suitable for practical application. Growing of layered Mn1-xCoxAs films with Co concentration changing gradually may draw layered active magnetic regenerator refrigerators closer to practical application. Our experimental result may provide the possibility for the combination of magnetocaloric effect and microelectronic circuitry. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467467] |
| ISSN: 0003-6951 |
| Article Number: 042502 |
| DOI: 10.1063/1.3467467 |
| Record 10 of 29 |
| Author(s): Guo, H (Guo Hao); Wu, P (Wu Ping); Yu, TB (Yu Tian-Bao); Liao, QH (Liao Qing-Hua); Liu, NH (Liu Nian-Hua); Huang, YZ (Huang Yong-Zhen) |
| Title: Design of novel polarization beam splitter in two-dimensional photonic crystal |
| Source: ACTA PHYSICA SINICA, 59 (8): 5547-5552 AUG 2010 |
| Abstract: We present the design and the simulation of an ultracompact high efficiency polarization beam splitter (PBS) based on the properties of the light waves propagating in straight waveguide and composite structure photonic crystal. The splitting properties of the PBS are numerically simulated and analyzed by using the plane wave expansion (PWE) method and finite difference time domain (FDTD) method. The PBS consists of three parts, namely, input waveguide, beam structure and output waveguide. It is shown that a high efficiency and a large separating angle for TE mode and TM mode can be achieved. Owing to these excellent features, including small size and high rate, the PBS makes a promising candidate in the future photonic integrated circuits. |
| ISSN: 1000-3290 |
| Record 11 of 29 |
| Author(s): Liu, XY (Liu Xiao-Yu); Ma, WQ (Ma Wen-Quan); Zhang, YH (Zhang Yan-Hua); Huo, YH (Huo Yong-Heng); Chong, M (Chong Ming); Chen, LH (Chen Liang-Hui) |
| Title: Two-color quantum well infrared photodetector simultaneously working at 10-14 mu m |
| Source: ACTA PHYSICA SINICA, 59 (8): 5720-5723 AUG 2010 |
| Abstract: We have demonstrated a two-color quantum well infrared photodetector (QWIP) exhibiting simultaneous photoresponse with cutoff wavelengths at 11.8 and 14.5 mu m, respectively. Strong photocurrent signals are observed at temperature of 77 K. The simultaneous two-color photoresponse is achieved by utilizing a simple design by broadening the width of the quantum well and selecting an appropriate doping density. The two peaks are attributed to the intersubband transitions from the ground state to the first excited state (bound state) and to the fifth excited state (continuum state), respectively. |
| ISSN: 1000-3290 |
| Record 12 of 29 |
| Author(s): Zhang, H (Zhang Han); Chen, NF (Chen NuoFu); Wang, Y (Wang Yu); Zhang, XW (Zhang XingWang); Yin, ZG (Yin ZhiGang); Shi, HW (Shi HuiWei); Wang, YS (Wang YanSuo); Huang, TM (Huang TianMao); Bai, YM (Bai YiMing); Fu, Z (Fu Zhen) |
| Title: Evaluating the effect of dislocation on the photovoltaic performance of metamorphic tandem solar cells |
| Source: SCIENCE CHINA-TECHNOLOGICAL SCIENCES, 53 (9): 2569-2574 SEP 2010 |
| Abstract: The photovoltaic conversion efficiency for monolithic GaInP/GaInAs/Ge triple-junction cell with various bandgap combination (300 suns, AM1.5d) was theoretically calculated. An impressive improvement on conversion efficiency was observed for a bandgap combination of 1.708, 1.194, and 0.67 eV. A theoretical investigation was carried out on the effect of dislocation on the metamorphic structure's efficiency by regarding dislocation as minority-carrier recombination center. The results showed that only when dislocation density was less than 1.6x10(6) cm(-2), can this metamorphic combination exhibit its efficiency advantage over the fully-matched combination. In addition, we also briefly evaluated the lattice misfit dependence of the dislocation density for a group of metamorphic triple-junction system, and used it as guidance for the choice of the proper cell structure. |
| ISSN: 1674-7321 |
| DOI: 10.1007/s11431-010-4015-3 |
| Record 13 of 29 |
| Author(s): Xu, X (Xu XingSheng); Chen, SA (Chen Shuai); Yamada, T (Yamada, Toshiki) |
| Title: Antibunching and blinking from a single colloidal CdSe quantum dot |
| Source: SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY, 53 (9): 1619-1625 SEP 2010 |
| Abstract: We have investigated the optical properties of single CdSe/ZnS nanocrystals by conducting combinations of experiments on antibunching and photoluminescence intermittence under different experimental conditions. Based on photoluminescence in an antibunching experiment, we analyzed the emission lifetime of QDs by using stretched exponentials. The difference between the parameters obtained from average lifetimes and stretched exponents were analyzed by considering the effect of nonradiative emission. An Auger-assisted tunneling model was used to explain the power law exponents of off time distribution. The power law exponent under high excitation power was correlated with a higher Auger ionization rate. Using the parameters obtained from stretched exponential function and power law, the antibunching phenomena at different time and under different excitation intensity were analyzed. |
| ISSN: 1674-7348 |
| DOI: 10.1007/s11433-010-4091-1 |
| Record 14 of 29 |
| Author(s): Ding, F (Ding, F.); Akopian, N (Akopian, N.); Li, B (Li, B.); Perinetti, U (Perinetti, U.); Govorov, A (Govorov, A.); Peeters, FM (Peeters, F. M.); Bufon, CCB (Bufon, C. C. Bof); Deneke, C (Deneke, C.); Chen, YH (Chen, Y. H.); Rastelli, A (Rastelli, A.); Schmidt, OG (Schmidt, O. G.); Zwiller, V (Zwiller, V.) |
| Title: Gate controlled Aharonov-Bohm-type oscillations from single neutral excitons in quantum rings |
| Source: PHYSICAL REVIEW B, 82 (7): Art. No. 075309 AUG 11 2010 |
| Abstract: We report on a magnetophotoluminescence study of single self-assembled semiconductor nanorings which are fabricated by molecular-beam epitaxy combined with AsBr3 in situ etching. Oscillations in the neutral exciton radiative recombination energy and in the emission intensity are observed under an applied magnetic field. Further, we control the period of the oscillations with a gate potential that modifies the exciton confinement. We infer from the experimental results, combined with calculations, that the exciton Aharonov-Bohm effect may account for the observed effects. |
| ISSN: 1098-0121 |
| Article Number: 075309 |
| DOI: 10.1103/PhysRevB.82.075309 |
| Record 15 of 29 |
| Author(s): Wang, LX (Wang, Li Xian); Zhu, NH (Zhu, Ning Hua); Ke, JH (Ke, Jian Hong); Li, W (Li, Wei); Chen, SF (Chen, Shuo Fu); Xie, LA (Xie, Liang) |
| Title: IMPROVED PEAK POWER METHOD FOR MEASURING FREQUENCY RESPONSES OF PHOTODETECTORS IN A SELF-HETERODYNE SYSTEM |
| Source: MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 52 (10): 2199-2203 OCT 2010 |
| Abstract: An improved peak power method for measuring frequency responses of photodetectors in a self-heterodyne system consisting of a distributed Bragg reflector laser is proposed. The time-resolved spectrum technique is used to measure the peak power of the beat signal and the intrinsic linewidth of heat signal for calibration. The experimental results show that the impact of the thermal-induced frequency drift, which is the main reason for producing an error in measurement by conventional peak power method and spectrum power method, can be removed. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2199-2203, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25448 |
| ISSN: 0895-2477 |
| DOI: 10.1002/mop.25448 |
| Record 16 of 29 |
| Author(s): Jiang, XN (Jiang, Xuena); Liu, YY (Liu, Yangyang); Wang, SJ (Wang, Shoujue) |
| Editor(s): Qiu, PH; Yiu, C; Zhang, H; Wen, XB |
| Title: A Novel Geometric Algorithm for Blind Image Restoration Based on High-Dimensional Space |
| Source: PROCEEDINGS OF THE 2009 2ND INTERNATIONAL CONGRESS ON IMAGE AND SIGNAL PROCESSING, VOLS 1-9: 762-766 2009 |
| Conference Title: 2nd International Congress on Image and Signal Processing |
| Conference Date: OCT 17-19, 2009 |
| Conference Location: Tianjin, PEOPLES R CHINA |
| Abstract: A novel geometric algorithm for blind image restoration is proposed in this paper, based on High-Dimensional Space Geometrical Informatics (HDSGI) theory. In this algorithm every image is considered as a point, and the location relationship of the points in high-dimensional space, i.e. the intrinsic relationship of images is analyzed. Then geometric technique of "blurring-blurring-deblurring" is adopted to get the deblurring images. Comparing with other existing algorithms like Wiener filter, super resolution image restoration etc., the experimental results show that the proposed algorithm could not only obtain better details of images but also reduces the computational complexity with less computing time. The novel algorithm probably shows a new direction for blind image restoration with promising perspective of applications. |
| ISBN: 978-1-4244-4130-3 |
| Record 17 of 29 |
| Author(s): Zhang, YC (Zhang Yu-Chi); Li, YA (Li Yuan); Guo, YQ (Guo Yan-Qiang); Li, G (Li Gang); Wang, JM (Wang Jun-Min); Zhang, TC (Zhang Tian-Cai) |
| Title: Degree of fourth-order coherence by double Hanbury Brown-Twiss detections |
| Source: CHINESE PHYSICS B, 19 (8): Art. No. 084205 AUG 2010 |
| Abstract: Photon quantum statistics of light can be shown by the high-order coherence. The fourth-order coherences of various quantum states including Pock states, coherent states, thermal states and squeezed vacuum states are investigated based on a double Banbury Brown Twiss (HBT) scheme. The analytical results are obtained by taking the overall efficiency and background into account. |
| ISSN: 1674-1056 |
| Article Number: 084205 |
| Record 18 of 29 |
| Author(s): Xu, HH (Xu Hai-Hua); Huang, QZ (Huang Qing-Zhong); Li, YT (Li Yun-Tao); Yu, YD (Yu Yu-De); Yu, JZ (Yu Jin-Zhong) |
| Title: Sub-nanosecond optical switch based on silicon racetrack resonator |
| Source: CHINESE PHYSICS B, 19 (8): Art. No. 084210 AUG 2010 |
| Abstract: We experimentally demonstrate a small-size and high-speed silicon optical switch based on the free carrier plasma dispersion in silicon. Using an embedded racetrack resonator with a quality factor of 7400, the optical switch shows an extinction ratio exceeding 13 dB with a footprint of only 2.2 x 10(-3) mm(2). Moreover, a novel pre-emphasis technique is introduced to improve the optical response performance and the rise and the fall times are reduced down to 0.24 ns and 0.42 ns respectively, which are 25% and 44% lower than those without the pre-emphasis. |
| ISSN: 1674-1056 |
| Article Number: 084210 |
| Record 19 of 29 |
| Author(s): Sun, GS (Sun Guo-Sheng); Liu, XF (Liu Xing-Fang); Wang, L (Wang Lei); Zhao, WS (Zhao Wan-Shun); Yang, T (Yang Ting); Wu, HL (Wu Hai-Lei); Yan, GG (Yan Guo-Guo); Zhao, YM (Zhao Yong-Mei); Ning, J (Ning Jin); Zeng, YP (Zeng Yi-Ping); Li, JM (Li Jin-Min) |
| Title: Multi-wafer 3C-SiC heteroepitaxial growth on Si(100) substrates |
| Source: CHINESE PHYSICS B, 19 (8): Art. No. 088101 AUG 2010 |
| Abstract: Epitaxial growth of semiconductor films in multiple-wafer mode is under vigorous development in order to improve yield output to meet the industry increasing demands. Here we report on results of the heteroepitaxial growth of multi-wafer 3C-SiC films on Si(100) substrates by employing a home-made horizontal hot wall low pressure chemical vapour deposition (HWLPCVD) system which was designed to be have a high-throughput, multi-wafer (3x2-inch) capacity. 3C-SiC film properties of the intra-wafer and the wafer-to-wafer including crystalline morphologies, structures and electronics are characterized systematically. The undoped and the moderate NH3 doped n-type 3C-SiC films with specular surface are grown in the HWLPCVD, thereafter uniformities of intra-wafer thickness and sheet resistance of the 3C-SiC films are obtained to be 6%similar to 7% and 6.7%similar to 8%, respectively, and within a run, the deviations of wafer-to-wafer thickness and sheet resistance are less than 1% and 0.8%, respectively. |
| ISSN: 1674-1056 |
| Article Number: 088101 |
| Record 20 of 29 |
| Author(s): Gu, YX (Gu Yong-Xian); Yang, T (Yang Tao); Ji, HM (Ji Hai-Ming); Xu, PF (Xu Peng-Fei); Wang, ZG (Wang Zhan-Guo) |
| Title: Impact of symmetrized and Burt-Foreman Hamiltonians on spurious solutions and energy levels of InAs/GaAs quantum dots |
| Source: CHINESE PHYSICS B, 19 (8): Art. No. 088102 AUG 2010 |
| Abstract: We present a systematic investigation of calculating quantum dots (QDs) energy levels using finite element method in the frame of eight-band k . p method. Numerical results including piezoelectricity, electron and hole levels, as yell as wave functions are achieved. In the calculation of energy levels, we do observe spurious solutions (SSs) no matter Burt-Foreman or symmetrized Hamiltonians are used. Different theories are used to analyse the SSs, we find that the ellipticity theory can give a better explanation for the origin of SSs and symmetrized Hamiltonian is easier to lead to SSs. The energy levels simulated with the two Hamiltonians are compared to each other after eliminating SSs, different Hamiltonians cause a larger difference on electron energy levels than that on hole energy levels and this difference decreases with the increase of QD size. |
| ISSN: 1674-1056 |
| Article Number: 088102 |
| Record 21 of 29 |
| Author(s): Xiao, X (Xiao, Xi); Xu, HH (Xu, Haihua); Zhou, LA (Zhou, Liang); Li, ZY (Li, Zhiyong); Li, YT (Li, Yuntao); Yu, YD (Yu, Yude); Yu, JZ (Yu, Jinzhong) |
| Title: Sub-nanosecond silicon-on-insulator optical micro-ring switch with low crosstalk |
| Source: CHINESE OPTICS LETTERS, 8 (8): 757-760 AUG 10 2010 |
| Abstract: We demonstrate a sub-nanosecond electro-optical switch with low crosstalk in a silicon-on-insulator (SOI) dual-coupled micro-ring embedded with p-i-n diodes. A crosstalk of -23 dB is obtained in the 20-mu m-radius micro-ring with the well-designing asymmetric dual-coupling structure. By optimizations of the doping profiles and the fabrication processes, the sub-nanosecond switch-on/off time of < 400 ps is finally realized under an electrical pre-emphasized driving signal. This compact and fast-response micro-ring switch, which can be fabricated by complementary metal oxide semiconductor (CMOS) compatible technologies, have enormous potential in optical interconnects of multicore networks-on-chip. |
| ISSN: 1671-7694 |
| DOI: 10.3788/COL20100808.0757 |
| Record 22 of 29 |
| Author(s): Zhao, CW (Zhao, C. W.); Xing, YM (Xing, Y. M.); Yu, JZ (Yu, J. Z.); Han, GQ (Han, G. Q.) |
| Title: Quantitative strain characterization of SiGe heterostructures by high-resolution transmission electron microscopy |
| Source: PHYSICA B-CONDENSED MATTER, 405 (16): 3433-3435 AUG 15 2010 |
| Abstract: We report the quantitative strain characterization in semiconductor heterostructures of silicon-germaniums (Si(0.76)Geo(0.24)) grown on Si substrate by an ultra-high vacuum chemical vapor deposition system. The relaxed SiGe virtual substrate has been achieved by thermal annealing of the SiGe film with an inserted Ge layer. Strain analysis was performed using a combination of high-resolution transmission electron microscopy and geometric phase analysis. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0921-4526 |
| DOI: 10.1016/j.physb.2010.05.018 |
| Record 23 of 29 |
| Author(s): Zhang, WT (Zhang, Wentao); Zhang, FX (Zhang, Faxiang); Li, F (Li, Fang); Liu, YL (Liu, Yuliang) |
| Title: Investigation on a pressure-gradient fiber laser hydrophone |
| Source: MEASUREMENT SCIENCE & TECHNOLOGY, 21 (9): Art. No. 094037 Sp. Iss. SI SEP 2010 |
| Abstract: In this paper, a pressure-gradient fiber laser hydrophone is demonstrated. Two brass diaphragms are installed at the end of a metal cylinder as sensing elements. A distributed feedback fiber laser, fixed at the center of the two diaphragms, is elongated or shortened due to the acoustic wave. There are two orifices at the middle of the cylinder. So this structure can work as a pressure-gradient microphone in the acoustic field. Furthermore, the hydrostatic pressure is self-compensated and an ultra-thin dimension is achieved. Theoretical analysis is given based on the electro-acoustic theory. Field trials are carried out to test the performance of the hydrophone. A sensitivity of 100 nm MPa-1 has been achieved. Due to the small dimensions, no directivity is found in the test. |
| ISSN: 0957-0233 |
| Article Number: 094037 |
| DOI: 10.1088/0957-0233/21/9/094037 |
| Record 24 of 29 |
| Author(s): Ma, J (Ma, J.); Guo, L (Guo, L.); Xiong, B (Xiong, B.); Yan, X (Yan, X.); Zhang, S (Zhang, S.); Chen, R (Chen, R.); Zhao, W (Zhao, W.); Lin, X (Lin, X.); Li, J (Li, J.); Duanmu, Q (Duanmu, Q.) |
| Title: A 20.1 W Solid-State Laser Pumped by 887 nm with High Efficiency and TEM00 Mode |
| Source: LASER PHYSICS, 20 (6): 1350-1353 JUN 2010 |
| Abstract: High efficiency, TEM00 mode, high repetition rate laser pumped by 887 nm is reported. 20.1 W output laser emitting at 1064 nm is achieved in a 0.3 at % Nd-doped Nd:YVO4, which absorbs pumping light of 30.7 W at 887 nm. The opto-optic efficiency and the slope efficiency are 65.5 and 88.5%, respectively. The stable Q-switching operation worked well at 100 kHz and the beam quality is near diffraction-limit with M-2 factor measured as M-2 approximate to 1.2. And the pulse waveform is analyzed in this paper. |
| ISSN: 1054-660X |
| DOI: 10.1134/S1054660X10110149 |
| Record 25 of 29 |
| Author(s): Zheng, J (Zheng, J.); Zuo, YH (Zuo, Y. H.); Zhang, LZ (Zhang, L. Z.); Wang, W (Wang, W.); Xue, CL (Xue, C. L.); Cheng, BW (Cheng, B. W.); Yu, JZ (Yu, J. Z.); Guo, HQ (Guo, H. Q.); Wang, QM (Wang, Q. M.) |
| Title: Role of Bi3+ ions for Er3+ ions efficient 1.54 mu m light emission in Er/Bi codoped SiO2 thin film prepared by sol-gel method |
| Source: JOURNAL OF LUMINESCENCE, 130 (10): 1760-1763 OCT 2010 |
| Abstract: Er/Bi codoped SiO2 thin films were prepared by sol-gel method and spin-on technology with subsequent annealing process. The bismuth silicate crystal phase appeared at low annealing temperature while vanished as annealing temperature exceeded 1000 degrees C, characterized by X-ray diffraction, and Rutherford backscattering measurements well explained the structure change of the films, which was due to the decrease of bismuth concentration. Fine structures of the Er3+-related 1.54 mu m light emission (line width less than 7 nm) at room temperature was observed by photoluminescence (PL) measurement. The PL intensity at 1.54 gm reached maximum at 800 degrees C and decreased dramatically at 1000 degrees C. The PL dependent annealing temperature was studied and suggested a clear link with bismuth silicate phase. Excitation spectrum measurements further reveal the role of Bi3+ ions for Er3+ ions near infrared light emission. Through sol-gel method and thermal treatment, Bi3+ ions can provide a perfect environment for Er3+ ion light emission by forming Er-Bi-Si-O complex. Furthermore, energy transfer from Bi3+ ions to Er3+ ions is evidenced and found to be a more efficient way for Er3+ ions near infrared emission. This makes the Bi3+ ions doped material a promising application for future erbium-doped waveguide amplifier and infrared LED. (C) 2010 Elsevier B.V. All rights reserved. |
| ISSN: 0022-2313 |
| DOI: 10.1016/j.jlumin.2010.04.006 |
| Record 26 of 29 |
| Author(s): Yang, C (Yang, C.); Cui, GX (Cui, G. X.); Huang, YY (Huang, Y. Y.); Wu, L (Wu, L.); Yang, H (Yang, H.); Zhang, YH (Zhang, Y. H.) |
| Title: Performance of an embedded optical vector matrix multiplication processor architecture |
| Source: IET OPTOELECTRONICS, 4 (4): 159-164 AUG 2010 |
| Abstract: An embedded architecture of optical vector matrix multiplier (OVMM) is presented. The embedded architecture is aimed at optimising the data flow of vector matrix multiplier (VMM) to promote its performance. Data dependence is discussed when the OVMM is connected to a cluster system. A simulator is built to analyse the performance according to the architecture. According to the simulation, Amdahl's law is used to analyse the hybrid opto-electronic system. It is found that the electronic part and its interaction with optical part form the bottleneck of system. |
| ISSN: 1751-8768 |
| DOI: 10.1049/iet-opt.2009.0012 |
| Record 27 of 29 |
| Author(s): He, LJ (He Ling-Juan); Xu, XM (Xu Xu-Ming); Liu, NH (Liu Nian-Hua); Yu, TB (Yu Tian-Bao); Fang, LG (Fang Li-Guang); Liao, QH (Liao Qing-Hua) |
| Title: Proposal of an Ultracompact Triplexer Using Photonic Crystal Waveguide with an Air Holes Array |
| Source: CHINESE PHYSICS LETTERS, 27 (8): Art. No. 084201 AUG 2010 |
| Abstract: We propose an ultracompact triplexer based on a shift of the cutoff frequency of the fundamental mode in a planar photonic crystal waveguide (PCW) with a triangular lattice of air holes. The shift is realized by modifying the radii of the border holes adjacent to the PCW core. Some defect holes are introduced to control the beam propagation. The numerical results obtained by the finite-difference time-domain method show that the presented triplexer can separate three specific wavelengths, i.e. 1310, 1490 and 1550 nm with the extinction ratios higher than - 18 dB. The designed device with a size as compact as 12 mu m x 6.5 mu m is feasible for the practical application, and can be utilized in the system of fiber to the home. |
| ISSN: 0256-307X |
| Article Number: 084201 |
| DOI: 10.1088/0256-307X/27/8/084201 |
| Record 28 of 29 |
| Author(s): Huo, YH (Huo, Y. H.); Ma, WQ (Ma, W. Q.); Zhang, YH (Zhang, Y. H.); Chen, LH (Chen, L. H.); Shi, YL (Shi, Y. L.) |
| Title: Quantum well infrared photodetector simultaneously working in two atmospheric windows |
| Source: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 100 (2): 415-419 Sp. Iss. SI AUG 2010 |
| Abstract: We have demonstrated a two-contact quantum well infrared photodetector (QWIP) exhibiting simultaneous photoresponse in both the mid- and the long-wavelength atmospheric windows of 3-5 mu m and of 8-12 mu m. The structure of the device was achieved by sequentially growing a mid-wavelength QWIP part followed by a long-wavelength QWIP part separated by an n-doped layer. Compared with the conventional dual-band QWIP device utilizing three ohmic contacts, our QWIP is promising to greatly facilitate two-color focal plane array (FPA) fabrication by reducing the number of the indium bumps per pixel from three to one just like a monochromatic FPA fabrication and to increase the FPA fill factor by reducing one contact per pixel; another advantage may be that this QWIP FPA boasts broadband detection capability in the two atmospheric windows while using only a monochromatic readout integrated circuit. We attributed this simultaneous broadband detection to the different distributions of the total bias voltage between the mid- and long-wavelength QWIP parts. |
| ISSN: 0947-8396 |
| DOI: 10.1007/s00339-010-5876-9 |
| Record 29 of 29 |
| Author(s): Wang, ZJ (Wang, Zhijie); Qu, SC (Qu, Shengchun); Zeng, XB (Zeng, Xiangbo); Liu, JP (Liu, Junpeng); Tan, FR (Tan, Furui); Bi, Y (Bi, Yu); Wang, ZG (Wang, Zhanguo) |
| Title: Organic/inorganic hybrid solar cells based on SnS/SnO nanocrystals and MDMO-PPV |
| Source: ACTA MATERIALIA, 58 (15): 4950-4955 SEP 2010 |
| Abstract: SnS/SnO heterojunction structured nanocrystals with zigzag rod-like connected morphology were prepared by using a simple two-step method. Bulk heterojunction solar cells were fabricated using the SnS/SnO nanocrystals blended with poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene) (MDMO-PPV) as the active layer. Compared with solar cells using SnS nanoparticles hybridized with MDMO-PPV as the active layer, the SnS/SnO devices showed better performance, with a power conversion efficiency higher by about one order in magnitude. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. |
| ISSN: 1359-6454 |
| DOI: 10.1016/j.actamat.2010.05.022 |
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