| Record 1 of 34 |
| Author(s): Sun, LL (Sun, Lili); Yan, FW (Yan, Fawang); Zhang, HX (Zhang, Huixiao); Wang, JX (Wang, Junxi); Zeng, YP (Zeng, Yiping); Wang, GH (Wang, Guohong); Li, JM (Li, Jinmin) |
| Title: The structure, morphology and Raman scattering study on Mn-implanted nonpolar a-plane GaN films |
| Source: MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS, 162 (3): 209-212 JUN 15 2009 |
| Abstract: Dilute magnetic nonpolar GaN films with a Curie temperature above room temperature have been fabricated by implanting Mn ions into unintentionally doped nonpolar a-plane (1 1 (2) over bar 0) GaN films and a subsequent rapid thermal annealing (RTA) process. The impact of the implantation and RTA on the structure and morphology of the nonpolar GaN films is studied in this paper. The scanning electron microscopy analysis shows that the RTA process can effectively recover the implantation-indUced damage to the surface morphology of the sample. The X-ray diffraction and micro-Raman scattering spectroscopy analyses show that the RTA process can just partially recover the implantation-induced crystal deterioration. Therefore, the quality of the Mn-implanted nonpolar GaN films should be improved further for the application in spintronic devices. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0921-5107 |
| DOI: 10.1016/j.mseb.2009.04.009 |
| Record 2 of 34 |
| Author(s): Gai, YQ (Gai, Yanqin); Li, JB (Li, Jingbo); Hou, QF (Hou, Qifeng); Wang, XL (Wang, Xiaoliang); Xiao, HL (Xiao, Hongling); Wang, CM (Wang, Cuimei); Li, JM (Li, Jinmin) |
| Title: Deep levels in high resistivity GaN detected by thermally stimulated luminescence and first-principles calculations |
| Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS, 42 (15): Art. No. 155403 AUG 7 2009 |
| Abstract: Thermally stimulated luminescence spectroscopy has been applied to study the deep centres in unintentionally doped high resistivity GaN epilayers grown by the metal organic chemical vapour deposition method on c-sapphire substrates. Two trap states with activation energies of 0.12 and 0.62 eV are evaluated from two luminescence peaks at 141.9 and 294.7 K in the luminescence curve. Our spectroscopy measurement, in combination with more accurate first-principles studies, provided insights into the microscopic origin of these levels. Our investigations suggest that the lower level at 0.12 eV might originate from C-N, which behaves as a hole trap state; the deeper level at 0.62 eV can be correlated with V-Ga that corresponds to the yellow luminescence band observed in low-temperature photoluminescence spectra. |
| ISSN: 0022-3727 |
| Article Number: 155403 |
| DOI: 10.1088/0022-3727/42/15/155403 |
| Record 3 of 34 |
| Author(s): Cai, PF (Cai, P. F.); You, JB (You, J. B.); Zhang, XW (Zhang, X. W.); Dong, JJ (Dong, J. J.); Yang, XL (Yang, X. L.); Yin, ZG (Yin, Z. G.); Chen, NF (Chen, N. F.) |
| Title: Enhancement of conductivity and transmittance of ZnO films by post hydrogen plasma treatment |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (8): Art. No. 083713 APR 15 2009 |
| Abstract: We studied the effects of hydrogen plasma treatment on the electrical and optical properties of ZnO films deposited by radio frequency magnetron sputtering. It is found that the ZnO:H film is highly transparent with the average transmittance of 92% in the visible range. Both carrier concentration and mobility are increased after hydrogen plasma treatment, correspondingly, the resistivity of the ZnO:H films achieves the order of 10(-3) cm. We suggest that the incorporated hydrogen not only passivates most of the defects and/or acceptors present, but also introduces shallow donor states such as the V-O-H complex and the interstitial hydrogen H-i. Moreover, the annealing data indicate that H-i is unstable in ZnO, while the V-O-H complex remains stable on the whole at 400 degrees C, and the latter diffuses out when the annealing temperature increases to 500 degrees C. These results make ZnO:H more attractive for future applications as transparent conducting electrodes. |
| ISSN: 0021-8979 |
| Article Number: 083713 |
| DOI: 10.1063/1.3108543 |
| Record 4 of 34 |
| Author(s): Wang, W (Wang, Wei); Yue, Y (Yue, Yuan); Li, DY (Li, Deyao) |
| Title: Anisotropy of magnetic properties in ferrimagnetic ytterbium iron garnet under high magnetic fields |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (8): Art. No. 083909 APR 15 2009 |
| Abstract: The magnetic anisotropy in ytterbium iron garnet (YbIG) is theoretically investigated under high magnetic fields (up to 160 kOe). According to the crystal field effect in ytterbium gallium garnet (YbGaG), a detailed discussion of crystal-field interaction in YbIG is presented where a suitable set of crystal-field parameters is obtained. Meanwhile, the influences of nine crystal-field parameters on the crystal-field energy splitting are analyzed. On the other hand, considering the ytterbium-iron (Yb-Fe) superexchange interaction of YbIG, the spontaneous magnetization is calculated at different temperatures for the [111] direction. In particular, we demonstrate that the Wesis constant lambda is the function of 1/T in YbIG. In addition, the field dependences of the magnetization for the [110] and [111] directions are theoretically described where a noticeable anisotropy can be found. Our theory further confirms the great contribution of anisotropic Yb-Fe superexchange interaction to the anisotropy of the magnetization in YbIG. Moreover, our theoretical results are compared with the available experiments. |
| ISSN: 0021-8979 |
| Article Number: 083909 |
| DOI: 10.1063/1.3109172 |
| Record 5 of 34 |
| Author(s): Lu, J (Lu, J.); Meng, HJ (Meng, H. J.); Deng, JJ (Deng, J. J.); Xu, PF (Xu, P. F.); Chen, L (Chen, L.); Zhao, JH (Zhao, J. H.); Jia, QJ (Jia, Q. J.) |
| Title: Strain and magnetic anisotropy of as-grown and annealed Fe films on c(4x4) reconstructed GaAs (001) surface |
| Source: JOURNAL OF APPLIED PHYSICS, 106 (1): Art. No. 013911 JUL 1 2009 |
| Abstract: Fe films with the different thicknesses were grown on c(4x4) reconstructed GaAs (001) surfaces at low temperature by molecular-beam epitaxy. Well-ordered bcc structural Fe epitaxial films are confirmed by x-ray diffraction patterns and high-resolution cross-sectional transmission electron microscopy images. A large lattice expansion perpendicular to the surface in Fe film is observed. In-plane uniaxial magnetic anisotropy is determined by the difference between magnetizing energy along [110] and [110] directions, and the constant of interfacial uniaxial magnetic anisotropy is calculated to be 1.02x10(-4) J m(-2). We also find that magnetic anisotropy is not obviously influenced after in situ annealing, but in-plane strain is completely changed. |
| ISSN: 0021-8979 |
| Article Number: 013911 |
| DOI: 10.1063/1.3159642 |
| Record 6 of 34 |
| Author(s): Zhang, HG (Zhang, Hong Guang); Zhu, NH (Zhu, Ning Hua); Man, JW (Man, Jiang Wei); Ke, JH (Ke, Jian Hong); Zhang, BH (Zhang, Bang Hong); Han, W (Han, Wei); Chen, W (Chen, Wei); Yuan, HQ (Yuan, Hai Qing); Wang, X (Wang, Xin); Xie, L (Xie, Liang); Zhao, LJ (Zhao, Ling Juan); Wang, W (Wang, Wei) |
| Title: Narrow-Linewidth Microwave Generation Using a Self-Injected DBR Laser Diode |
| Source: IEEE PHOTONICS TECHNOLOGY LETTERS, 21 (15): 1045-1047 AUG 1 2009 |
| Abstract: A novel technique for generating narrow-linewidth microwave or millimeter-wave signals is proposed. In this scheme, a delayed self-injected distributed Bragg reflector laser diode, which is tuned by a low-frequency square-wave voltage, is used to generate two correlated lightwaves simultaneously. Experiments show that the 10-dB linewidth of generated microwave signals is reduced from 147 MHz to 68 kHz utilizing the proposed self-injection technique. |
| ISSN: 1041-1135 |
| DOI: 10.1109/LPT.2009.2022176 |
| Record 7 of 34 |
| Author(s): Song, HP (Song, Huaping); Yang, AL (Yang, Anli); Zhang, RQ (Zhang, Riqing); Guo, Y (Guo, Yan); Wei, HY (Wei, Hongyuan); Zheng, GL (Zheng, Gaolin); Yang, SY (Yang, Shaoyan); Liu, XL (Liu, Xianglin); Zhu, QS (Zhu, Qinsheng); Wang, ZG (Wang, Zhanguo) |
| Title: Well-Aligned Zn-Doped InN Nanorods Grown by Metal-Organic Chemical Vapor Deposition and the Dopant Distribution |
| Source: CRYSTAL GROWTH & DESIGN, 9 (7): 3292-3295 JUL 2009 |
| Abstract: We report the synthesis and characterization of Zn-doped InN nanorods by metal-organic chemical vapor deposition. Electron microscopy images show that the InN nanorods are single-crystalline structures and vertically well-aligned. Energy-dispersive X-ray spectroscopy analyses suggest that Zn ions are distributed nonhomogenously in InN nanorods. Simulations based on diffusion model show that the doping concentration along the radial direction of InN nanorod is bowl-like: from the exterior to the interior, the doping concentration decreases, and Such dopant distribution result in a bimodal EDXS spectrum of Zn across the nanorod. The study of the mechanism of doping effect is useful for the design of InN-based nanometer devices. Also, high-quality Zn-doped InN nanorods will be very attractive as building blocks for nano-optoelectronic devices.' |
| ISSN: 1528-7483 |
| DOI: 10.1021/cg900053h |
| Record 8 of 34 |
| Author(s): Wang, LJ (Wang Liang-Ji); Zhang, SM (Zhang Shu-Ming); Wang, YT (Wang Yu-Tian); Jiang, DS (Jiang De-Sheng); Zhu, JJ (Zhu Jian-Jun); Zhao, DG (Zhao De-Gang); Liu, ZS (Liu Zong-Shun); Wang, H (Wang Hui); Shi, YS (Shi Yong-Sheng); Wang, H (Wang Hai); Liu, SY (Liu Su-Ying); Yang, H (Yang Hui) |
| Title: Curvature Correction of FWHM in the X-Ray Rocking Curve of Bent Heteroepitaxial Films |
| Source: CHINESE PHYSICS LETTERS, 26 (7): Art. No. 076104 JUL 2009 |
| Abstract: A method for accurate determination of the curvature radius of semiconductor thin films is proposed. The curvature-induced broadening of the x-ray rocking curve (XRC) of a heteroepitaxially grown layer can be determined if the dependence of the full width at half maximum (FWHM) of XRC is measured as a function of the width of incident x-ray beam. It is found that the curvature radii of two GaN films grown on a sapphire wafer are different when they are grown under similar MOCVD conditions but have different values of layer thickness. At the same time, the dislocation-induced broadening of XRC and thus the dislocation density of the epitaxial film can be well calculated after the curvature correction. |
| ISSN: 0256-307X |
| Article Number: 076104 |
| Record 9 of 34 |
| Author(s): Hao, YF (Hao Ya-Fei); Chen, YH (Chen Yong-Hai); Hao, GD (Hao Guo-Dong); Wang, ZG (Wang Zhan-Guo) |
| Title: Electric Field Control of Interface Related Spin Splitting in Step Quantum Wells |
| Source: CHINESE PHYSICS LETTERS, 26 (7): Art. No. 077104 JUL 2009 |
| Abstract: Spin splitting of the AlyGa1-yAs/GaAs/AlxGa1-xAs/AlyGa1-yAs (x not equal y) step quantum wells (QWs) has been theoretically investigated with a model that includes both the interface and the external electric field contribution. The overall spin splitting is mainly determined by the interface contribution, which can be well manipulated by the external electric field. In the absence of the electric field, the Rashba effect exists due to the internal structure inversion asymmetry (SIA). The electric field can strengthen or suppress the internal SIA, resulting in an increase or decrease of the spin splitting. The step QW, which results in large spin splitting, has advantages in applications to spintronic devices compared with symmetrical and asymmetrical QWs. Due to the special structure design, the spin splitting does not change with the external electric field. |
| ISSN: 0256-307X |
| Article Number: 077104 |
| Record 10 of 34 |
| Author(s): Jiang, LJ (Jiang Li-Juan); Wang, XL (Wang Xiao-Liang); Xiao, HL (Xiao Hong-Ling); Wang, ZG (Wang Zhan-Guo); Feng, C (Feng Chun); Zhang, ML (Zhang Min-Lan); Tang, J (Tang Jian) |
| Title: Structural and Magnetic Properties of Sm Implanted GaN |
| Source: CHINESE PHYSICS LETTERS, 26 (7): Art. No. 077502 JUL 2009 |
| Abstract: The structural and magnetic properties of Sm ion-implanted GaN with different Sm concentrations are investigated. XRD results do not show any peaks associated with second phase formation. Magnetic investigations performed by superconducting quantum interference device reveal ferromagnetic behavior with an ordering temperature above room temperature in all the implanted samples, while the effective magnetic moment per Sm obtained from saturation magnetization gives a much higher value than the atomic moment of Sm. These results could be explained by the phenomenological model proposed by Dhar et al. [Phys. Rev. Lett. 94(2005) 037205, Phys. Rev. B 72(2005) 245203] in terms of a long-range spin polarization of the GaN matrix by the Sm atoms. |
| ISSN: 0256-307X |
| Article Number: 077502 |
| Record 11 of 34 |
| Author(s): Su, Q (Su Qian); An, D (An Dong); Zhai, YF (Zhai Yafeng); Wang, K (Wang Ku); Wang, SJ (Wang Shoujue) |
| Title: A Cancer Recognition Method Based on DNA Microarray |
| Source: CHINESE JOURNAL OF ELECTRONICS, 18 (3): 491-493 JUL 2009 |
| Abstract: The accurate cancer classification is of great importance in clinical treatment. Recently, the DNA microarray technology provides a promising approach to the diagnosis and prognosis of cancer types. However, it has no perfect method for the multiclass classification problem. The difficulty lies in the fact that the data are of high dimensionality with small sample size. This paper proposed an automatic classification method of multiclass cancers based on Biomimetic pattern recognition (BPR). To the public GCM data set, the average correct classification rate reaches 80% under the condition that the correct rejection rate is 81%. |
| ISSN: 1022-4653 |
| Record 12 of 34 |
| Author(s): Huang, YZ (Huang, Yong-Zhen); Wang, SJ (Wang, Shi-Jiang); Yang, YD (Yang, Yue-De); Xiao, JL (Xiao, Jin-Long); Hu, YH (Hu, Yong-Hong); Du, Y (Du, Yun) |
| Title: Optical bistability in InP/GaInAsP equilateral-triangle-resonator microlasers |
| Source: OPTICS LETTERS, 34 (12): 1852-1854 JUN 15 2009 |
| Abstract: Optical bistability is reported in InP/GaInAsP equilateral-triangle-resonator (ETR) microlasers, which are fabricated by planar technology. For a 30 mu m side ETR microlaser with a 2-mu m-wide output waveguide connected to one of the vertices of the ETR, hysteresis loops are observed for the output power versus the injection current from 215 to 235 K. The laser output spectra are measured in the upper and lower states of the hysteresis loop, which show strong mode competition among transverse modes. The hysteresis loops are demonstrated by two-mode rate equations with asymmetric cross gain saturation and different output efficiencies. (C) 2009 Optical Society of America |
| ISSN: 0146-9592 |
| Record 13 of 34 |
| Author(s): Wang, H (Wang, H.); Jiang, DS (Jiang, D. S.); Zhu, JJ (Zhu, J. J.); Zhao, DG (Zhao, D. G.); Liu, ZS (Liu, Z. S.); Wang, YT (Wang, Y. T.); Zhang, SM (Zhang, S. M.); Yang, H (Yang, H.) |
| Title: Kinetically controlled InN nucleation on GaN templates by metalorganic chemical vapour deposition |
| Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS, 42 (14): Art. No. 145410 JUL 21 2009 |
| Abstract: This paper presents a study on the nucleation and initial growth kinetics of InN on GaN, especially their dependence on metalorganic chemical vapour deposition conditions. It is found that the density and size of separated InN nano-scale islands can be adjusted and well controlled by changing the V/III ratio and growth temperature. InN nuclei density increases for several orders of magnitude with decreasing growth temperature between 525 and 375 degrees C. At lower growth temperatures, InN thin films take the form of small and closely packed islands with diameters less than 100 nm, whereas at elevated temperatures the InN islands grow larger and become well separated, approaching an equilibrium hexagonal shape due to enhanced surface diffusion of adatoms. The temperature dependence of InN island density gives two activation energies of InN nucleation behaviour, which is attributed to two different kinetic processes related to In adatom surface diffusion and desorption, respectively. |
| ISSN: 0022-3727 |
| Article Number: 145410 |
| DOI: 10.1088/0022-3727/42/14/145410 |
| Record 14 of 34 |
| Author(s): Wang, W (Wang, Wei); Li, DY (Li, Deyao) |
| Title: Properties of exchange interaction in Yb3Fe5O12 under extreme conditions |
| Source: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 321 (19): 3307-3310 OCT 2009 |
| Abstract: In Yb3Fe5O12, the exchange effective field can be expressed as H-eff = -lambda center dot center dot center dot M-Fe = -lambda chi(eff)center dot center dot center dot H-e = -gamma center dot center dot center dot H-e where gamma is named as the exchange field parameter and H-e is the external magnetic field. Then, in this paper, by the discussions on the characteristics of the exchange field parameter gamma, the properties of exchange interaction in ytterbium iron garnet (Yb3Fe5O12) are analyzed under extreme conditions (high magnetic fields and low temperatures). Our theory suggests that the exchange field parameter gamma is the function of the temperatures under different external magnetic fields, and gamma = a+b center dot center dot center dot T+c center dot center dot center dot T-2, where the coefficients a, b, c are associated with the external magnetic fields and the magnetized directions. Thus, the temperature-dependence, field-dependence and anisotropic characteristics of the exchange interaction in Yb3Fe5O12 are revealed. Also, excellent fits to the available experiments are obtained. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0304-8853 |
| DOI: 10.1016/j.jmmm.2009.05.068 |
| Record 15 of 34 |
| Author(s): Guo, J (Guo Jie); Peng, ZY (Peng Zhen-Yu); Lu, ZX (Lu Zheng-Xiong); Sun, WG (Sun Wei-Guo); Hao, RT (Hao Rui-Ting); Zhou, ZQ (Zhou Zhi-Qiang); Xu, YQ (Xu Ying-Qiang); Niu, ZC (Niu Zhi-Chuan) |
| Title: SHORT PERIOD InAs/GaSb SUPERLATTICE INFRARED DETECTOR ON GaAs SUBSTRATES |
| Source: JOURNAL OF INFRARED AND MILLIMETER WAVES, 28 (3): 165-+ JUN 2009 |
| Abstract: Two type II superlattices (SLs) : InAs(2ML)/GaSb(8ML) and InAs(8ML)/GaSb(8ML) were grown on GaAs substrates by molecular-beam epitaxy. High resolution X-ray diffraction showed the periods of the two SLs were 31.2 angstrom and 57.3 angstrom, respectively. Room-temperature optical transmittance spectra showed that there were clear absorption edges at 2.1 mu m and 5 mu m for the two SLs. The SWIR and MWIR photoconductor devices were fabricated by standard lithography and etched by tartaric acid solution. The spectral response and blackbody tests were carried out at low and room temperatues. The results show that the 50% cutoff wavelengths of the two photoconductors are 2.1 mu m and 5.0 mu m respectively and D-bb* is above 2 x 10(8) cmHz(1/2)/W for two kinds of photoconductors at 77K. D-bb* is above 10(8) cmHz(1/2)/W for SWIR photoconductor at room temperature. |
| ISSN: 1001-9014 |
| Record 16 of 34 |
| Author(s): Wang, ZJ (Wang, Zhijie); Qu, SC (Qu, Shengchun); Zeng, XB (Zeng, Xiangbo); Liu, JP (Liu, Junpeng); Zhang, CS (Zhang, Changsha); Tan, FR (Tan, Furui); Jin, L (Jin, Lan); Wang, ZG (Wang, Zhanguo) |
| Title: The application of SnS nanoparticles to bulk heterojunction solar cells |
| Source: JOURNAL OF ALLOYS AND COMPOUNDS, 482 (1-2): 203-207 AUG 12 2009 |
| Abstract: Tin mono-sulphide (SnS) nanoparticles were synthesized by a facile method. Reactions producing narrow size distribution SnS nanoparticles with the diameter of 5.0-10 nm were carried out in an ethylene glycol solution at 150 degrees C for 24 h. Bulk heterojunction solar cells with the structure of indium tin oxide (ITO)/polyethylenedioxythiophene:polystyrenesulphonate (PEDOT:PSS)/SnS:polymer/Al were fabricated by blending the nanoparticles with a conjugated polymer to form the active layer for the first time. Current density-voltage characterization of the devices showed that due to the addition of SnS nanoparticles to the polymer film, the device performance can be dramatically improved, compared with that of the pristine polymer solar cells. (c) 2009 Published by Elsevier B.V. |
| ISSN: 0925-8388 |
| DOI: 10.1016/j.jallcom.2009.03.158 |
| Record 17 of 34 |
| Author(s): Wang, H (Wang Huan); Zhu, HL (Zhu Hong-Liang); Jia, LH (Jia Ling-Hui); Chen, XF (Chen Xiang-Fei); Kong, DH (Kong Duan-Hua); Wang, LS (Wang Lie-Song); Zhang, W (Zhang Wei); Zhao, LJ (Zhao Ling-Juan); Wang, W (Wang Wei) |
| Title: Application of sampled grating to control the lasing wavelength in complex-coupled DFB laser |
| Source: CHINESE PHYSICS B, 18 (7): 2868-2872 JUL 2009 |
| Abstract: This paper reports that the complex-coupled distributed feedback laser with the sampled grating has been designed and fabricated. The +1st order reflection of the sampled grating is utilized for laser single mode operation, which is 1.5387 mu m in the experiment. The typical threshold current of the device is 30 mA, and the optical output power is about 10 mW at the injection current of 100 mA. |
| ISSN: 1674-1056 |
| Record 18 of 34 |
| Author(s): Ding, WC (Ding Wu-Chang); Liu, Y (Liu Yan); Zhang, Y (Zhang Yun); Guo, JC (Guo Jian-Chuan); Zuo, YH (Zuo Yu-Hua); Cheng, BW (Cheng Bu-Wen); Yu, JZ (Yu Jin-Zhong); Wang, QM (Wang Qi-Ming) |
| Title: A comparison of silicon oxide and nitride as host matrices on the photoluminescence from Er3+ ions |
| Source: CHINESE PHYSICS B, 18 (7): 3044-3048 JUL 2009 |
| Abstract: This paper compares the properties of silicon oxide and nitride as host matrices for Er ions. Erbium-doped silicon nitride films were deposited by a plasma-enhanced chemical-vapour deposition system. After deposition, the films were implanted with Er3+ at different doses. Er-doped thermal grown silicon oxide films were prepared at the same time as references. Photoluminescence features of Er3+ were inspected systematically. It is found that silicon nitride films are suitable for high concentration doping and the thermal quenching effect is not severe. However, a very high annealing temperature up to 1200 degrees C is needed to optically activate Er3+ which may be the main obstacle to impede the application of Er-doped silicon nitride. |
| ISSN: 1674-1056 |
| Record 19 of 34 |
| Author(s): Wang, H (Wang, H.); Wang, LL (Wang, L. L.); Sun, X (Sun, X.); Zhu, JH (Zhu, J. H.); Liu, WB (Liu, W. B.); Jiang, DS (Jiang, D. S.); Zhu, JJ (Zhu, J. J.); Zhao, DG (Zhao, D. G.); Liu, ZS (Liu, Z. S.); Wang, YT (Wang, Y. T.); Zhang, SM (Zhang, S. M.); Yang, H (Yang, H.) |
| Title: Suppression of indium droplet formation by adding CCl4 during metalorganic chemical vapor deposition growth of InN films |
| Source: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 24 (7): Art. No. 075004 JUL 2009 |
| Abstract: In this work, the influences of CCl4 on the metalorganic chemical vapor deposition (MOCVD) growth of InN were studied for the first time. It was found that the addition of CCl4 can effectively suppress the formation of metal indium (In) droplets during InN growth, which was ascribed to the etching effect of Cl to In. However, with increasing of CCl4 flow, the InN growth rate decreased but the lateral growth of InN islands was enhanced. This provides a possibility of promoting islands coalescence toward a smooth surface of the InN film by MOCVD. The influence of addition of CCl4 on the electrical properties was also investigated. |
| ISSN: 0268-1242 |
| Article Number: 075004 |
| DOI: 10.1088/0268-1242/24/7/075004 |
| Record 20 of 34 |
| Author(s): Liu, JQ (Liu, Junqi); Liu, FQ (Liu, Fengqi); Li, L (Li, Lu); Wang, LJ (Wang, Lijun); Wang, ZG (Wang, Zhanguo) |
| Title: A mini-staged multi-stacked quantum cascade laser for improved optical and thermal performance |
| Source: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 24 (7): Art. No. 075023 JUL 2009 |
| Abstract: In this paper, a mini-staged multi-stacked quantum cascade laser structure with a designed wavelength of 4.7 mu m is presented. By introducing five 0.5 mu m thick high thermal conductivity InP interbuffer layers, the 60-stages active region core of the quantum cascade laser is divided into six equal parts. Based on simulation, this kind of quantum cascade laser with a 10 mu m ridge width gives nearly circular two-dimensional far-field distribution (FWHM = 32.8 degrees x 29 degrees) and good beam quality parameters M-2 = 1.32 x 1.31 in the fast axis (growth direction) and the slow axis (lateral direction). Due to the enhancement of lateral heat extraction through the interbuffer layers, compared to the conventional structure, a decrease of about 5-6% for the maximum temperature in the active region core of the mini-staged multi-stacked quantum cascade laser with indium-surrounded and gold-electroplated packaging profiles is obtained at all possible dissipated electrical power levels. |
| ISSN: 0268-1242 |
| Article Number: 075023 |
| DOI: 10.1088/0268-1242/24/7/075023 |
| Record 21 of 34 |
| Author(s): He, J (He, Jun); Li, F (Li, Fang); Feng, L (Feng, Lei); Xiao, H (Xiao, Hao); Liu, YL (Liu, Yuliang) |
| Title: Elimination of environmental noise in interferometric wavelength shift demodulation for dynamic fiber Bragg grating sensor array |
| Source: OPTICS COMMUNICATIONS, 282 (14): 2836-2840 JUL 15 2009 |
| Abstract: We present a novel reference compensation method for eliminating environmental noise in interferometric wavelength shift demodulation for dynamic fiber Bragg grating (FBG) sensors. By employing a shielded wavelength-division-multiplexed reference FBG in the system the environmental noise is mea, sured from the reference channel, and then subtracted from the demodulation result of each sensor channel. An approximate 40 dB reduction of the environmental noise has been experimentally achieved over a frequency range from 20 Hz to 2 kHz. This method is also suitable for the elimination of broadband environmental noise. The corresponding FBG sensor array system proposed in this paper has shown a wave-length resolution of 7 x 10(-4) pm/root Hz. (c) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0030-4018 |
| DOI: 10.1016/j.optcom.2009.04.010 |
| Record 22 of 34 |
| Author(s): Zhang, B (Zhang, Bo); Chen, J (Chen, Jing); Wang, X (Wang, Xi); Wu, AM (Wu, Aimin); Luo, JX (Luo, Jiexin); Wang, X (Wang, Xi); Zhang, MA (Zhang, Miao); Wu, YX (Wu, Yuxin); Zhu, JJ (Zhu, Jianjun); Yang, H (Yang, Hui) |
| Title: EPITAXIAL LATERAL OVERGROWTH OF GaN ON SILICON-ON-INSULATOR |
| Source: MODERN PHYSICS LETTERS B, 23 (15): 1881-1887 JUN 20 2009 |
| Abstract: From a single process, GaN layers were laterally overgrown on maskless stripe-patterned (111) silicon-on-insulator (SOI) substrates by metalorganic chemical vapor deposition. The influence of stress on the behavior of dislocations at the coalescence during growth was observed using transmission electron microscopy (TEM). Improvement of the crystallin equality of the GaN layer was demonstrated by TEM and micro-Raman spectroscopy. Furthermore, the benefits of SOI substrates for GaN growth are also discussed. |
| ISSN: 0217-9849 |
| Record 23 of 34 |
| Author(s): Chen, J (Chen, J.); Fan, WJ (Fan, W. J.); Xu, Q (Xu, Q.); Zhang, XW (Zhang, X. W.); Li, SS (Li, S. S.); Xia, JB (Xia, J. B.) |
| Title: Electronic structure and optical gain saturation of InAs1-xNx/GaAs quantum dots |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (12): Art. No. 123705 JUN 15 2009 |
| Conference Title: 29th International Conference on Physics of Semiconductors |
| Conference Date: JUL 27-AUG 01, 2008 |
| Conference Location: Rio de Janeiro, BRAZIL |
| Abstract: The electronic band structures and optical gains of InAs1-xNx/GaAs pyramid quantum dots (QDs) are calculated using the ten-band k . p model and the valence force field method. The optical gains are calculated using the zero-dimensional optical gain formula with taking into consideration of both homogeneous and inhomogeneous broadenings due to the size fluctuation of quantum dots which follows a normal distribution. With the variation of QD sizes and nitrogen composition, it can be shown that the nitrogen composition and the strains can significantly affect the energy levels especially the conduction band which has repulsion interaction with nitrogen resonant state due to the band anticrossing interaction. It facilitates to achieve emission of longer wavelength (1.33 or 1.55 mu m) lasers for optical fiber communication system. For QD with higher nitrogen composition, it has longer emission wavelength and less detrimental effect of higher excited state transition, but nitrogen composition can affect the maximum gain depending on the factors of transition matrix element and the Fermi-Dirac distributions for electrons in the conduction bands and holes in the valence bands respectively. For larger QD, its maximum optical gain is greater at lower carrier density, but it is slowly surpassed by smaller QD as carrier concentration increases. Larger QD can reach its saturation gain faster, but this saturation gain is smaller than that of smaller QD. So the trade-off between longer wavelength, maximum optical, saturation gain, and differential gain must be considered to select the appropriate QD size according to the specific application requirement. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3143025] |
| ISSN: 0021-8979 |
| Article Number: 123705 |
| DOI: 10.1063/1.3143025 |
| Record 24 of 34 |
| Author(s): Du, GX (Du, G. X.); Babu, MR (Babu, M. Ramesh); Han, XF (Han, X. F.); Deng, JJ (Deng, J. J.); Wang, WZ (Wang, W. Z.); Zhao, JH (Zhao, J. H.); Wang, WD (Wang, W. D.); Tang, JK (Tang, Jinke) |
| Title: Tunneling magnetoresistance in (Ga,Mn)As/Al-O/CoFeB hybrid structures |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (7): Art. No. 07C707 APR 1 2009 |
| Conference Title: 53rd Annual Conference on Magnetism and Magnetic Materials |
| Conference Date: NOV 11-14, 2008 |
| Conference Location: Austin, TX |
| Abstract: Tunneling magnetoresistance (TMR) in Ga(0.9)2Mn(0.08)As/Al-O/Co40Fe40B20 trilayer hybrid structure as a function of temperature from 10 to 50 K with magnetic field vertical bar H vertical bar <= 2000 Oe has been studied. TMR ratio of 1.6% at low fields at 10 K was achieved with the applied current of 1 mu A. The behavior of junction resistance was well explained by the tunneling resistance across the barrier. Strong bias dependences of magnetoresistance and junction resistance were presented. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3068418] |
| ISSN: 0021-8979 |
| Article Number: 07C707 |
| DOI: 10.1063/1.3068418 |
| Record 25 of 34 |
| Author(s): Sun, L (Sun, Lei); Zhou, WZ (Zhou, Wenzheng); Yu, GL (Yu, Guolin); Shang, LY (Shang, Liyan); Gao, KH (Gao, Kuanghong); Zhou, YM (Zhou, Yuanming); Lin, T (Lin, Tie); Cui, LJ (Cui, Lijie); Zeng, YP (Zeng, Yiping); Chu, JH (Chu, Junhao) |
| Title: Strong Spin-Orbit Interactions in an InAlAs/InGaAs/InAlAs Two-Dimensional Electron Gas by Weak Antilocalization Analysis |
| Source: JAPANESE JOURNAL OF APPLIED PHYSICS, 48 (6): Art. No. 063004 Part 1 JUN 2009 |
| Abstract: Spin-orbit interactions in a two-dimensional electron gas were studied in an InAlAs/InGaAs/InAlAs quantum well. Since weak anti localization effects take place far beyond the diffusive regime, (i.e., the ratio of the characteristic magnetic field, at which the magnetoresistance correction maximum occurs, to the transport magnetic field is more than ten) the experimental data are examined by the Golub theory, which is applicable to both diffusive regime and ballistic regime. Satisfactory fitting lines to the experimental data have been achieved using the Golub theory. In the strong spin-orbit interaction two-dimensional electron gas system, the large spin splitting energy of 6.08 meV is observed mainly due to the high electron concentration in the quantum well. The temperature dependence of the phase-breaking rate is qualitatively in agreement with the theoretical predictions. (C) 2009 The Japan Society of Applied Physics |
| ISSN: 0021-4922 |
| Article Number: 063004 |
| DOI: 10.1143/JJAP.48.063004 |
| Record 26 of 34 |
| Author(s): Yao, Y (Yao, Yuan); Wu, J (Wu, Jie); Shi, Y (Shi, Yin); Dai, FF (Dai, Fa Foster) |
| Title: A Fully Integrated 900-MHz Passive RFID Transponder Front End With Novel Zero-Threshold RF-DC Rectifier |
| Source: IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, 56 (7): 2317-2325 JUL 2009 |
| Abstract: This paper presents a fully integrated CMOS analog front end for a passive 900-MHz radio-frequency identification (RFID) transponder. The power supply in this front end is generated from the received RF electromagnetic energy by using an RF-dc voltage rectifier. In order to improve the compatibility with standard CMOS technology, Schottky diodes in conventional RF-dc rectifiers are replaced by diode-connected MOS transistors with zero threshold. Meanwhile, theoretical analyses for the proposed rectifier are provided and verified by both simulation and measurement results. The design considerations of the pulsewidth-modulation (PWM) demodulator and the backscatter modulator in the front end are also discussed for low-power applications. The proposed front end is implemented in a 0.35-mu m 2P4M CMOS technology. The whole chip occupies a die area of 490 x 780 mu m(2) and consumes only 2.1 mu W in reading mode under a self-generated 1.5-V supply voltage. The measurement results show that the proposed rectifier can properly operate with a - 14.7-dBm input RF power at a power conversion efficiency of 13.0%. In the proposed RFID applications, this sensitivity corresponds to 10.88-m communication distance at 4-W equivalent isotropically radiated power from a reader base station. |
| ISSN: 0278-0046 |
| DOI: 10.1109/TIE.2008.2010180 |
| Record 27 of 34 |
| Author(s): Yang, ZC (Yang, Z. C.); Huang, AP (Huang, A. P.); Yan, L (Yan, L.); Xiao, ZS (Xiao, Z. S.); Zhang, XW (Zhang, X. W.); Chu, PK (Chu, Paul K.); Wang, WW (Wang, W. W.) |
| Title: Role of interface dipole in metal gate/high-k effective work function modulation by aluminum incorporation |
| Source: APPLIED PHYSICS LETTERS, 94 (25): Art. No. 252905 JUN 22 2009 |
| Abstract: The interface dipole and its role in the effective work function (EWF) modulation by Al incorporation are investigated. Our study shows that the interface dipole located at the high-k/SiO2 interface causes an electrostatic potential difference across the metal/high-k interface, which significantly shifts the band alignment between the metal and high-k, consequently modulating the EWF. The electrochemical potential equalization and electrostatic potential methods are used to evaluate the interface dipole and its contribution. The calculated EWF modulation agrees with experimental data and can provide insight to the control of EWF in future pMOS technology. |
| ISSN: 0003-6951 |
| Article Number: 252905 |
| DOI: 10.1063/1.3159830 |
| Record 28 of 34 |
| Author(s): You, JB (You, J. B.); Zhang, XW (Zhang, X. W.); Cai, PF (Cai, P. F.); Dong, JJ (Dong, J. J.); Gao, Y (Gao, Y.); Yin, ZG (Yin, Z. G.); Chen, NF (Chen, N. F.); Wang, RZ (Wang, R. Z.); Yan, H (Yan, H.) |
| Title: Enhancement of field emission of the ZnO film by the reduced work function and the increased conductivity via hydrogen plasma treatment |
| Source: APPLIED PHYSICS LETTERS, 94 (26): Art. No. 262105 JUN 29 2009 |
| Abstract: The ZnO films deposited by magnetron sputtering were treated by H/O plasma. It is found that the field emission (FE) characteristics of the ZnO film are considerably improved after H-plasma treatment and slightly deteriorated after O-plasma treatment. The improvement of FE characteristics is attributed to the reduced work function and the increased conductivity of the ZnO:H films. Conductive atomic force microscopy was employed to investigate the effect of the plasma treatment on the nanoscale conductivity of ZnO, these findings correlate well with the FE data and facilitate a clearer description of electron emission from the ZnO:H films. |
| ISSN: 0003-6951 |
| Article Number: 262105 |
| DOI: 10.1063/1.3167301 |
| Record 29 of 34 |
| Author(s): Zhang, Z (Zhang, Z.); Zhang, R (Zhang, R.); Xie, ZL (Xie, Z. L.); Liu, B (Liu, B.); Li, M (Li, M.); Fu, DY (Fu, D. Y.); Fang, HN (Fang, H. N.); Xiu, XQ (Xiu, X. Q.); Lu, H (Lu, H.); Zheng, YD (Zheng, Y. D.); Chen, YH (Chen, Y. H.); Tang, CG (Tang, C. G.); Wang, ZG (Wang, Z. G.) |
| Title: Observation of the surface circular photogalvanic effect in InN films |
| Source: SOLID STATE COMMUNICATIONS, 149 (25-26): 1004-1007 JUL 2009 |
| Abstract: A sizable spin-dependent photocurrent related to the interband transition in InN films is observed. The surface charge accumulation layer is suggested to be the origin of the circular photogalvanic current, which is consistent with the result of uniaxial strain experiments and the comparison of front and back incidence. The homogeneous photocurrent demonstrates the existence of spin splitting in the InN surface layer, and the structure inversion asymmetry (SIA)-dominant mechanism indicates a great possibility for the manipulation of spin splitting, which would undoubtedly benefit further research and applications of spintronics. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved. |
| ISSN: 0038-1098 |
| DOI: 10.1016/j.ssc.2009.04.008 |
| Record 30 of 34 |
| Author(s): Pan, SD (Pan, S. D.); Zhao, LN (Zhao, L. N.); Yuan, Y (Yuan, Y.); Zhu, SN (Zhu, S. N.); He, JL (He, J. L.); Wang, YG (Wang, Y. G.) |
| Title: High efficiency passively Q-switched mode-locking Nd:GdVO4 laser with LT-In0.25Ga0.75As saturable absorber |
| Source: OPTICAL MATERIALS, 31 (8): 1215-1217 JUN 2009 |
| Abstract: The generation of passively Q-switched mode-locking operation with 100% modulation depth has been observed from a diode-pumped Nd:GdVO4 laser with a low temperature In0.25Ga0.75As saturable absorber, which was grown by the metal-organic chemical-vapor deposition technique and acted as saturable absorber as well as output coupler. The repetition rate and pulse duration of the mode-locked pulses concentrated in the Q-switch envelop were 455 MHz and 12 ps, respectively. The average output power was 1.8 W and the slope efficiency was 36%. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0925-3467 |
| DOI: 10.1016/j.optmat.2009.01.004 |
| Record 31 of 34 |
| Author(s): Jia, CH (Jia, Caihong); Chen, YH (Chen, Yonghai); Zhang, WF (Zhang, W. F.) |
| Title: Optical properties of aluminum-, gallium-, and indium-doped Bi4Ti3O12 thin films |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (11): Art. No. 113108 JUN 1 2009 |
| Abstract: Undoped and Al-, Ga-, and In-doped Bi4Ti3O12 thin films were prepared on fused quartz substrates by chemical solution deposition. Their microstructures and optical properties were investigated by x-ray diffraction and UV-visible-NIR spectrophotometer, respectively. The optical band-gap energies, Urbach energies, and linear refractive indices of all the films are derived from the transmittance spectrum. Following the single oscillator model, the dispersion parameters such as the average oscillator energy (E-0) and dispersion energy (E-d) are achieved. The energy band gap and refractive indices are found to decrease with introducing the dopants of Al, Ga, and In, which is useful for the band-gap engineering and optical waveguide devices. The refractive index dispersion parameter (E-0/S-0) increases and the chemical bonding quantity (beta) decreases in all the films compared with those of bulk. It is supposed to be caused by the nanosize grains in films. (c) 2009 American Institute of Physics. [DOI: 10.1063/1.3138813] |
| ISSN: 0021-8979 |
| Article Number: 113108 |
| DOI: 10.1063/1.3138813 |
| Record 32 of 34 |
| Author(s): Gai, YQ (Gai, Yanqin); Li, JB (Li, Jingbo); Yao, B (Yao, Bin); Xia, JB (Xia, Jian-Bai) |
| Title: The bipolar doping of ZnS via native defects and external dopants |
| Source: JOURNAL OF APPLIED PHYSICS, 105 (11): Art. No. 113704 JUN 1 2009 |
| Abstract: By employing first-principle total-energy calculations, a systematic study of the dopability of ZnS to be both n- and p-types compared with that of ZnO is carried out. We find that all the attempted acceptor dopants, group V substituting on the S lattice site and group I and IB on the Zn sites in ZnS, have lower ionization energies than the corresponding ones in ZnO. This can be accounted for by the fact that ZnS has relative higher valence band maximum than ZnO. Native ZnS is weak p-type under S-rich condition, as the abundant acceptor V-Zn has rather large ionization energy. Self-compensations by the formation of interstitial donors in group I and IB-doped p-type ZnS can be avoided when sample is prepared under S-rich condition. In terms of ionization energies, Li-Zn and N-S are the preferred acceptors in ZnS. Native n- type doping of ZnS is limited by the spontaneous formation of intrinsic V-Zn(2-); high efficient n-type doping with dopants is harder to achieve than in ZnO because of the readiness of forming native compensating centers and higher ionization energy of donors in ZnS. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3103585] |
| ISSN: 0021-8979 |
| Article Number: 113704 |
| DOI: 10.1063/1.3103585 |
| Record 33 of 34 |
| Author(s): Wei, QX (Wei, Quanxiang); Ren, ZW (Ren, Zhengwei); He, ZH (He, Zhenhong); Niu, ZC (Niu, Zhichuan) |
| Title: Evolution of surface morphology and photoluminescence characteristics of 1.3-mu m In0.5Ga0.5As/GaAs quantum dots grown by molecular beam epitaxy |
| Source: CHINESE OPTICS LETTERS, 7 (1): 52-55 JAN 10 2009 |
| Abstract: Evolution of surface morphology and optical characteristics of 1.3-mu m In0.5Ga0.5As/GaAs quantum dots (QDs) grown by molecular beam epitaxy (MBE) are investigated by atomic force microscopy (AFM) and photoluminescence (PL). After deposition of 16 monolayers (ML) of In0.5Ga0.5As, QDs are formed and elongated along the [110] direction when using sub-ML depositions, while large size InGaAs QDs with better uniformity are formed when using ML or super-ML depositions. It is also found that the larger size QDs show enhanced PL efficiency without optical nonlinearity, which is in contrast to the elongated QDs. |
| ISSN: 1671-7694 |
| DOI: 10.3788/COL20090701.0052 |
| Record 34 of 34 |
| Author(s): Chen, W (Chen Wei); Xing, MX (Xing Ming-Xin); Ren, G (Ren Gang); Wang, K (Wang Ke); Du, XY (Du Xiao-Yu); Zhang, YJ (Zhang Ye-Jin); Zheng, WH (Zheng Wan-Hua) |
| Title: Design of high polarization and single-mode photonic crystal laser |
| Source: ACTA PHYSICA SINICA, 58 (6): 3955-3960 JUN 2009 |
| Abstract: The dipole mode in triangular photonic crystal single defect cavity is degenerate. By deforming the lattice in photonic crystal we can obtain non-degenerate dipole modes. Lattice deforming in the whole photonic crystal destroys the characteristic of symmetry, so the distribution of the electromagnetic field is affected and the polarization of the electromagnetic field is also changed. Lattice deforming divides the degenerate dipole mode into the x-dipole mode and the y-dipole mode. It is found that the non-degenerate modes have better properties of polarization. So the high polarization and single dipole mode photonic crystal laser can be achieved by deforming the lattice of photonic crystal. In this paper, we simulated the cavity in photonic crystal slab and mainly calculated the quality factor of x-dipole mode under different deforming conditions and with different filling factors. The properties of polarization of x-dipole and y-dipole modes are also calculated. It is found that the ratio of intensities of E-x to E-y in x-dipole mode and that of E-y to E-x in y-dipole mode are 44 and 27, respectively. |
| ISSN: 1000-3290 |
|
