|
| Record 1 of 12 |
| Author(s): Zhao, DG (Zhao, D. G.); Jiang, DS (Jiang, D. S.); Zhu, JJ (Zhu, J. J.); Wang, H (Wang, H.); Liu, ZS (Liu, Z. S.); Zhang, SM (Zhang, S. M.); Wang, YT (Wang, Y. T.); Jia, QJ (Jia, Q. J.); Yang, H (Yang, Hui) |
| Title: An experimental study about the influence of well thickness on the electroluminescence of InGaN/GaN multiple quantum wells |
| Source: JOURNAL OF ALLOYS AND COMPOUNDS, 489 (2): 461-464 JAN 21 2010 |
| Abstract: The influence of well thickness on the electroluminescence (EL) of InGaN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition is investigated. It is found that the peak wavelength of EL increases with the increase of well thickness when the latter is located in the range of 3.0-5.1 nm. The redshift is mainly attributed to the quantum confined Stark effect (QCSE). As a contrast, it is found that the EL intensity of InGaN/GaN MQWs increases with the increase of well thickness in spite of QCSE. The result of X-ray diffraction demonstrates that the interface become smoother with the increase of well thickness and suggests that the reduced interface roughness can be an important factor leading to the increase of EL intensity of InGaN/GaN MQWs. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0925-8388 |
| DOI: 10.1016/j.jallcom.2009.09.086 |
| Record 2 of 12 |
| Author(s): Chen, J (Chen, Jing); Wang, X (Wang, Xi); Wu, AM (Wu, Aimin); Zhang, B (Zhang, Bo); Wang, X (Wang, Xi); Wu, YX (Wu, Yuxin); Zhu, JJ (Zhu, Jianjun); Yang, H (Yang, Hui) |
| Title: Study of GaN epilayers growth on freestanding Si cantilevers |
| Source: SOLID-STATE ELECTRONICS, 54 (1): 4-7 JAN 2010 |
| Abstract: Five-micron thick freestanding Si cantilevers were fabricated on bulk Si (1 1 1) substrates with surface/bulk micromachining (SBM) process. Then 1-mu m thick GaN layers were deposited on the Si cantilevers by metal-organic chemical vapor deposition (MOCVD). Epilayers on cantilever areas were obtained crack-free, and the photoluminescence (PL) spectra verified the stress reduction and better material quality in these suspended parts of GaN. Back sides of the cantilevers were also covered with GaN layers, which prevented the composite beams from bending dramatically. This paper had proved the feasibility of integrating high-quality GaN epilayers with Si micromechanical structures to realize GaN-based micro electro-mechanical system (MEMS). (C) 2009 Elsevier Ltd. All rights reserved. |
| ISSN: 0038-1101 |
| DOI: 10.1016/j.sse.2009.10.008 |
| Record 3 of 12 |
| Author(s): Zhou, B (Zhou, Bi); Pan, SW (Pan, S. W.); Chen, R (Chen, Rui); Chen, SY (Chen, S. Y.); Li, C (Li, Cheng); Lai, HK (Lai, H. K.); Yu, JZ (Yu, J. Z.); Zhu, XF (Zhu, X. F.) |
| Title: Strain-induced anodization of SiGe/Si multiple layers to form high density SiGe/Si heterogeneous nanorods |
| Source: SOLID STATE COMMUNICATIONS, 149 (43-44): 1897-1901 NOV 2009 |
| Abstract: SiGe/Si heterogeneous nanostructures are prepared by electrochemical anodization of SiGe/Si multiple layers grown by ultra-high vacuum chemical vapor deposition. Nanorods with densities up to similar to 2 x 10(11) cm(-2) have been observed with a relatively uniform distribution confirmed by scanning electron microscope images of both top and cross-sectional views. The samples show visible photoluminescence with multiple peaks and narrow widths which is related to the interference effect. Finally, a model is proposed to explain the role of strain during the anodization of SiGe/Si multiple layers. (C) 2009 Elsevier Ltd. All rights reserved. |
| ISSN: 0038-1098 |
| DOI: 10.1016/j.ssc.2009.08.001 |
| Record 4 of 12 |
| Author(s): Lu, J (Lu, J.); Xu, PF (Xu, P. F.); Zhu, YG (Zhu, Y. G.); Meng, HJ (Meng, H. J.); Chen, L (Chen, L.); Wang, WZ (Wang, W. Z.); Zhang, XH (Zhang, X. H.); Zhao, JH (Zhao, J. H.); Pan, GQ (Pan, G. Q.) |
| Title: Anisotropic strain relaxation of thin Fe film on c(4 x 4) reconstructed GaAs (001) surface |
| Source: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 42 (2): 150-153 DEC 2009 |
| Abstract: We report the interplay between the anisotropic strain relaxation and the in-plane uniaxial magnetic anisotropy in a 5 nm Fe film grown on GaAs (0 0 1) by molecular-beam epitaxy. Tetragonal distortion and in-plane anisotropic strain relaxation were accurately measured by synchrotron X-ray diffraction. A stronger coherence at the interface between Fe and GaAs is also observed in the annealed film. A competing model including magnetocrystalline anisotropy, interface anisotropy, and magnetoelastic anisotropy is proposed to characterize the in-plane magnetic anisotropy. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 1386-9477 |
| DOI: 10.1016/j.physe.2009.09.017 |
| Record 5 of 12 |
| Author(s): Zhao, L (Zhao, Lei); Diao, HW (Diao, Hongwei); Zeng, XB (Zeng, Xiangbo); Zhou, CL (Zhou, Chunlan); Li, HL (Li, Hailing); Wang, WJ (Wang, Wenjing) |
| Title: Comparative study of the surface passivation on crystalline silicon by silicon thin films with different structures |
| Source: PHYSICA B-CONDENSED MATTER, 405 (1): 61-64 JAN 1 2010 |
| Abstract: Si thin films with different structures were deposited by plasma enhanced chemical vapor deposition (PECVD), and characterized via Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The passivation effect of such different Si thin films on crystalline Si surface was investigated by minority carrier lifetime measurement via a method, called microwave photoconductive decay (mu PCD), for the application in HIT (heterojunction with intrinsic thin-layer) solar cells. The results show that amorphous silicon (a-Si:H) has a better passivation effect due to its relative higher H content, compared with microcrystalline (mu c-Si) silicon and nanocrystalline silicon (nc-Si). Further, it was found that H atoms in the form of Si-H bonds are more preferred than those in the form of Si-H-2 bonds to passivate the crystalline Si surface. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0921-4526 |
| DOI: 10.1016/j.physb.2009.08.024 |
| Record 6 of 12 |
| Author(s): Geng, MM (Geng, Minming); Jia, LX (Jia, Lianxi); Zhang, L (Zhang, Lei); Yang, L (Yang, Lin); Chen, P (Chen, Ping); Liu, YL (Liu, Yuliang) |
| Title: Compact four-channel reconfigurable optical add-drop multiplexer using silicon photonic wire (vol 282, pg 3477, 2009) |
| Source: OPTICS COMMUNICATIONS, 283 (3): 515-515 FEB 1 2010 |
| ISSN: 0030-4018 |
| DOI: 10.1016/j.optcom.2009.10.071 |
| Record 7 of 12 |
| Author(s): Gao, Y (Gao, Y.); Zhang, XW (Zhang, X. W.); Yin, ZG (Yin, Z. G.); Qu, S (Qu, S.); You, JB (You, J. B.); Chen, NF (Chen, N. F.) |
| Title: Magnetic Properties of FePt Nanoparticles Prepared by a Micellar Method |
| Source: NANOSCALE RESEARCH LETTERS, 5 (1): 1-6 JAN 2010 |
| Abstract: FePt nanoparticles with average size of 9 nm were synthesized using a diblock polymer micellar method combined with plasma treatment. To prevent from oxidation under ambient conditions, immediately after plasma treatment, the FePt nanoparticle arrays were in situ transferred into the film-growth chamber where they were covered by an SiO2 overlayer. A nearly complete transformation of L1(0) FePt was achieved for samples annealed at temperatures above 700 A degrees C. The well control on the FePt stoichiometry and avoidance from surface oxidation largely enhanced the coercivity, and a value as high as 10 kOe was obtained in this study. An evaluation of magnetic interactions was made using the so-called isothermal remanence (IRM) and dc-demagnetization (DCD) remanence curves and Kelly-Henkel plots (Delta M measurement). The Delta M measurement reveals that the resultant FePt nanoparticles exhibit a rather weak interparticle dipolar coupling, and the absence of interparticle exchange interaction suggests no significant particle agglomeration occurred during the post-annealing. Additionally, a slight parallel magnetic anisotropy was also observed. The results indicate the micellar method has a high potential in preparing FePt nanoparticle arrays used for ultrahigh density recording media. |
| ISSN: 1931-7573 |
| DOI: 10.1007/s11671-009-9433-4 |
| Record 8 of 12 |
| Author(s): Zhang, J (Zhang, Jing); Cai, LK (Cai, Likang); Bai, WL (Bai, Wenli); Xu, Y (Xu, Yun); Song, GF (Song, Guofeng) |
| Title: Slow light at terahertz frequencies in surface plasmon polariton assisted grating waveguide |
| Source: JOURNAL OF APPLIED PHYSICS, 106 (10): Art. No. 103715 NOV 15 2009 |
| Abstract: A subwavelength grating waveguide (GW) consisting of two parallel metallic slabs with periodic corrugations on their inner boundaries is developed to slow down the speed of light at terahertz frequencies. Assisted by a tapered input port, our structure has a transfer efficiency of about 80% over a broad bandwidth and strong confinement in the subwavelength scale. Based on the GW, three graded GWs are designed to demonstrate that the spoof Surface plasmon polaritons are slowed down and asymptotically stopped when they tend to the location, where the local cutoff frequency is the same as the frequency of the incident light. (C) 2009 American Institute of Physics. [doi:10.1063/1.3260236] |
| ISSN: 0021-8979 |
| Article Number: 103715 |
| DOI: 10.1063/1.3260236 |
| Record 9 of 12 |
| Author(s): Chang, XY (Chang, X. Y.); Dou, XM (Dou, X. M.); Sun, BQ (Sun, B. Q.); Xiong, YH (Xiong, Y. H.); Niu, ZC (Niu, Z. C.); Ni, HQ (Ni, H. Q.); Jiang, DS (Jiang, D. S.) |
| Title: Optical transitions of positively charged excitons and biexcitons in single InAs quantum dots |
| Source: JOURNAL OF APPLIED PHYSICS, 106 (10): Art. No. 103716 NOV 15 2009 |
| Abstract: We investigate fine structures observed in the optical transitions of positively charged excitons and biexcitons in single quantum dots. We show that double charged biexciton XX2+ emits into a hot double charged exciton X2+* at first, and then relaxes into charged excitons X2+ or X2+ states via phonon scattering or Auger process respectively. XX2+ gives rise to two elliptically polarized emission lines due to the mixing of two lower-levels in the final state. X2+ causes two optical transitions with different polarizations, i.e., a linearly polarized emission with a fine structure splitting of 45 mu eV and a circularly polarized emission with twofold degeneracy. (C) 2009 American Institute of Physics. [doi:10.1063/1.3262607] |
| ISSN: 0021-8979 |
| Article Number: 103716 |
| DOI: 10.1063/1.3262607 |
| Record 10 of 12 |
| Author(s): Zhang, B (Zhang, B.); Lu, YW (Lu, Y. W.); Song, HP (Song, H. P.); Liu, XL (Liu, X. L.); Yang, SY (Yang, S. Y.); Zhu, QS (Zhu, Q. S.); Wang, ZG (Wang, Z. G.) |
| Title: Depolarization blueshift in intersubband transitions of triangular quantum wires |
| Source: JOURNAL OF APPLIED PHYSICS, 106 (11): Art. No. 113712 DEC 1 2009 |
| Abstract: The depolarization effect (DE) in the intersubband transitions (ISBTs) of triangular cross-section quantum wires has been calculated in the framework of the effective-mass envelope-function theory and the self-consistent field approximation (Hartree approximation). Similar to quantum wells, the DE can bring an upward shift in ISBT. The shift quantities are affected significantly by apex angle but are insensitive to triangle size. |
| ISSN: 0021-8979 |
| Article Number: 113712 |
| DOI: 10.1063/1.3267475 |
| Record 11 of 12 |
| 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: Strong room-temperature ferromagnetism in Cu-implanted nonpolar GaN films |
| Source: JOURNAL OF APPLIED PHYSICS, 106 (11): Art. No. 113921 DEC 1 2009 |
| Abstract: Diluted magnetic nonpolar GaN:Cu films with ferromagnetic properties up to 380 K have been fabricated by implantation of Cu ions into nonpolar a-plane GaN films and a subsequent thermal annealing process. The nonpolar GaN:Cu films exhibit a strong saturation magnetization about 1.54 mu(B)/Cu atom, while polar GaN:Cu films can only show a weak saturation magnetization of 0.36 mu(B)/Cu atom. Moreover, according to the x-ray photoelectron spectroscopy results, the stronger ferromagnetism of nonpolar GaN:Cu films may be resulted from the higher Cu incorporation efficiency in nonpolar GaN films. |
| ISSN: 0021-8979 |
| Article Number: 113921 |
| DOI: 10.1063/1.3266013 |
| Record 12 of 12 |
| Author(s): Gai, YQ (Gai, Yanqin); Peng, HW (Peng, Haowei); Li, JB (Li, Jingbo) |
| Title: Electronic Properties of Nonstoichiometric PbSe Quantum Dots from First Principles |
| Source: JOURNAL OF PHYSICAL CHEMISTRY C, 113 (52): 21506-21511 DEC 31 2009 |
| Abstract: The electronic properties of PbSe quantum dots containing a nonstoichiometric Pb:Se ratio are investigated by A initio density functional theory. We take five nearly spherical PbSe nanocrystals with effective diameters ranging from 11.22 to 31.86 angstrom into account and compare their electronic properties before and after passivations. We find that despite the strong ionic character of the Pb-Se bond, their dangling bonds at the surface of nonstoichiometric PbSe nanocrystals introduce in-gap states, which are quite different from those of the stoichiometric PbSe nanocrystals. The same phenomenon is also observed for bare PbSe (011) and (111) surfaces. Compared with that of the self-passivated (001) surface, there is large surface relaxation and rumpling at the unsaturated (011) and (111) surfaces. We expect this might also be the origin of surface states in nonstoichiometric PbSe nanocrystals. We observed the almost recovery of structures and at the same time the elimination of in-gap states by passivating the dangling bonds with pseudo-hydrogen atoms. Meanwhile, the size dependencies of the QDs' gaps are obtained, which are in accordance with experimental measurement and other theoretical calculations. |
| ISSN: 1932-7447 |
| DOI: 10.1021/jp905868f |
|
