| Record 1 of 11 |
| Author(s): Han, Y (Han, Y.); Li, WY (Li, W. Y.); Cao, LX (Cao, L. X.); Wang, XY (Wang, X. Y.); Xu, B (Xu, B.); Zhao, BR (Zhao, B. R.); Guo, YQ (Guo, Y. Q.); Yang, JL (Yang, J. L.) |
| Title: Superconductivity in Iron Telluride Thin Films under Tensile Stress |
| Source: PHYSICAL REVIEW LETTERS, 104 (1): Art. No. 017003 JAN 8 2010 |
| Abstract: By realizing in thin films a tensile stress state, superconductivity of 13 K was introduced into FeTe, a nonsuperconducting parent compound of the iron pnictides and chalcogenides, with a transition temperature higher than that of its superconducting isostructural counterpart FeSe. For these tensile stressed films, superconductivity is accompanied by a softening of the first-order magnetic and structural phase transition, and also, the in-plane extension and out-of-plane contraction are universal in all FeTe films independent of the sign of the lattice mismatch, either positive or negative. Moreover, the correlations were found to exist between the transition temperatures and the tetrahedra bond angles in these thin films. |
| ISSN: 0031-9007 |
| Article Number: 017003 |
| DOI: 10.1103/PhysRevLett.104.017003 |
| Record 2 of 11 |
| Author(s): Wang, BT (Wang, Bao-Tian); Shi, HL (Shi, Hongliang); Li, WD (Li, Weidong); Zhang, P (Zhang, Ping) |
| Title: First-principles LDA plus U and GGA plus U study of neptunium dioxide |
| Source: PHYSICAL REVIEW B, 81 (4): Art. No. 045119 JAN 2010 |
| Abstract: We have performed a systematic first-principles investigation to calculate the electronic structures, mechanical properties, and phonon-dispersion curves of NpO2. The local-density approximation+U and the generalized gradient approximation+U formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Np 5f electrons. By choosing the Hubbard U parameter around 4 eV, the orbital occupancy characters of Np 5f and O 2p are in good agreement with recent experiments [A. Seibert, T. Gouder, and F. Huber, J. Nucl. Mater. 389, 470 (2009)]. Comparing to our previous study of ThO2, we note that stronger covalency exists in NpO2 due to the more localization behavior of 5f electrons of Np in line with the localization-delocalization trend exhibited by the actinides series. |
| ISSN: 1098-0121 |
| Article Number: 045119 |
| DOI: 10.1103/PhysRevB.81.045119 |
| Record 3 of 11 |
| Author(s): Liu, SM (Liu, Shu-Man); Chen, W (Chen, Wei); Wang, ZG (Wang, Zhan-Guo) |
| Title: Luminescence Nanocrystals for Solar Cell Enhancement |
| Source: JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 10 (3): 1418-1429 Sp. Iss. SI MAR 2010 |
| Abstract: Semiconductor nanocrystals (NCs) prepared by wet-chemical routes have been proposed as an attractive candidate for fabrication of the third-gene ration thin-film solar cells due to their quantum confinement effects and excellent dispersion ability in polymer films. However, to date, a solar cell incorporating semiconductor NCs in the photoactive layer still has rather low efficiency due to the low carrier mobility of the non-continued NC phase and the possible radiative recombination in NCs. To avoid these disadvantages, NCs have been proposed and applied as a luminescent species in a passive photon converting layer to modify the solar spectrum before the light enters the photovoltaic device. Photon conversion processes, including up-conversion, down-conversion, and down-shifting, have been observed in various colloidal NC samples and have great potential to enhance photovoltaic performance when applied to the existing single-junction solar cells or narrow-band molecular-based devices. |
| ISSN: 1533-4880 |
| DOI: 10.1166/jnn.2010.2023 |
| Record 4 of 11 |
| Author(s): Xia, JB (Xia Jianbai) |
| Title: A new year message from Chinese Science Bulletin |
| Source: CHINESE SCIENCE BULLETIN, 55 (1): 1-1 JAN 2010 |
| ISSN: 1001-6538 |
| DOI: 10.1007/s11434-010-0034-5 |
| Record 5 of 11 |
| Author(s): Liu, AJ (Liu AnJin); Qu, HW (Qu HongWei); Xing, MX (Xing MingXin); Chen, W (Chen Wei); Zhou, WJ (Zhou WenJun); Meng, WH (Meng WanHua) |
| Title: A novel photonic crystal vertical cavity surface emitting laser based on coherent coupling |
| Source: CHINESE SCIENCE BULLETIN, 55 (2): 111-113 JAN 2010 |
| Abstract: We demonstrate a novel oxide confined GaAs-based photonic crystal vertical cavity surface emitting laser (PC-VCSEL) operating at a wavelength of 850 nm based on coherent coupling. A ring-shaped light-emitting aperture is added to the conventional PC-VCSEL, and coherent coupling is achieved between the central defect aperture and the ring-shaped light-emitting aperture. Measurements show that under the continuous-wave (CW) injected current of 20 mA, a high power of 2 mW is obtained, and the side mode suppression ratio (SMSR) is larger than 20 dB. The average divergence angle is 4.2 degrees at the current level of 20 mA. Compared with the results ever reported, the divergence angle is reduced. |
| ISSN: 1001-6538 |
| DOI: 10.1007/s11434-009-0317-x |
| Record 6 of 11 |
| Author(s): Liu, SH (Liu, Shihua); Liu, J (Liu, Jie); Wang, GG (Wang, Guanggang); Li, L (Li, Lei); Liu, SS (Liu, Shushan); Liu, M (Liu, Min); Wang, YG (Wang, Yonggang) |
| Title: Low-threshold diode-pumped CW passively mode-locked Nd:YVO4 laser |
| Source: OPTIK, 121 (1): 19-22 2010 |
| Abstract: A low-threshold passively continuous-wave (CW) mode-locked Nd:YVO4 solid-state laser was demonstrated by use of a semiconductor saturable absorber mirror (SESAM). The threshold for continuous-wave mode-locked is relatively low, about 2.15 W. The maximum average output power was 2.12 W and the optical to optical conversion efficiency was about 32%. The pulse width was about 15 ps with the repetition rate of 105 MHz. (C) 2008 Elsevier GmbH. All rights reserved. |
| ISSN: 0030-4026 |
| DOI: 10.1016/j.ijleo.2008.05.006 |
| Record 7 of 11 |
| Author(s): Zhang, JY (Zhang, J. Y.); Wang, XF (Wang, X. F.); Wang, XD (Wang, X. D.); Fan, ZC (Fan, Z. C.); Li, Y (Li, Y.); Ji, A (Ji, An); Yang, FH (Yang, F. H.) |
| Title: Selective and lithography-independent fabrication of 20 nm nano-gap electrodes and nano-channels for nanoelectrofluidics applications |
| Source: NANOTECHNOLOGY, 21 (7): Art. No. 075303 FEB 19 2010 |
| Abstract: A new method has been developed to selectively fabricate nano-gap electrodes and nano-channels by conventional lithography. Based on a sacrificial spacer process, we have successfully obtained sub-100-nm nano-gap electrodes and nano-channels and further reduced the dimensions to 20 nm by shrinking the sacrificial spacer size. Our method shows good selectivity between nano-gap electrodes and nano-channels due to different sacrificial spacer etch conditions. There is no length limit for the nano-gap electrode and the nano-channel. The method reported in this paper also allows for wafer scale fabrication, high throughput, low cost, and good compatibility with modern semiconductor technology. |
| ISSN: 0957-4484 |
| Article Number: 075303 |
| DOI: 10.1088/0957-4484/21/7/075303 |
| Record 8 of 11 |
| Author(s): Zheng, J (Zheng, J.); Ding, WC (Ding, W. C.); Xue, CL (Xue, C. L.); Zuo, YH (Zuo, Y. H.); Cheng, BW (Cheng, B. W.); Yu, JZ (Yu, J. Z.); Wang, QM (Wang, Q. M.); Wang, GL (Wang, G. L.); Guo, HQ (Guo, H. Q.) |
| Title: Highly efficient photoluminescence of Er2SiO5 films grown by reactive magnetron sputtering method |
| Source: JOURNAL OF LUMINESCENCE, 130 (3): 411-414 MAR 2010 |
| Abstract: E2SiO5 thin films were fabricated on Si substrate by reactive magnetron sputtering method with subsequent annealing treatment. The morphology properties of as-deposited films have been studied by scanning electron microscope. The fraction of erbium is estimated to be 23.5 at% based on Rutherford backscattering measurement in as-deposited Er-Si-O film. X-ray diffraction measurement revealed that Er2SiO5 crystalline structure was formed as sample treated at 1100 degrees C for 1 h in O-2 atmosphere. Through proper thermal treatment, the 1.53 mu m Er3+-related emission intensity can be enhanced by a factor of 50 with respect to the sample annealed at 800 degrees C. Analysis of pump-power dependence of Er3+ PL intensity indicated that the upconversion phenomenon could be neglected even under a high photon flux of 10(21) (photons/cm(2)/sec). Temperature-dependent photoluminescence (PL) of Er2SiO5 was studied and showed a weak thermal quenching factor of 2. Highly efficienct photoluminescence of Er2SiO5 films has been demonstrated with Er3+ concentration of 10(22)/cm(3), and it opens a promising way towards future Si-based light source for Si photonics. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0022-2313 |
| DOI: 10.1016/j.jlumin.2009.10.005 |
| Record 9 of 11 |
| Author(s): Zhang, LQ (Zhang Li-Qun); Zhang, SM (Zhang Shu-Ming); Jiang, DS (Jiang De-Sheng); Wang, H (Wang Hui); Zhu, JJ (Zhu Jian-Jun); Zhao, DG (Zhao De-Gang); Liu, ZS (Liu Zong-Shun); Yang, H (Yang Hui) |
| Title: GaN-based violet laser diodes grown on free-standing GaN substrate |
| Source: CHINESE PHYSICS B, 18 (12): 5350-5353 DEC 2009 |
| Abstract: A violet laser diode (LD) structure is grown on a free-standing c-plane GaN substrate and 4 mu m x 800 mu m ridge waveguide LDs are fabricated. The electrical and the optical characteristics of LDs under different facet-coating and chip-mounting conditions are investigated under pulse mode operation. The active region temperatures of p-side up and p-side down mounted LDs are calculated with different injection currents. The calculated thermal resistances of p-side up and p-side down mounted LDs are 4.6 K/W and 3 K/W, respectively. The threshold current of the p-side down mounted LD is much lower than that of the p-side up mounted LD. The blue shift of the emission wavelength with increasing injection current is observed only for the LD with p-side down mounting configuration, due to the more efficient heat dissipation. |
| ISSN: 1674-1056 |
| Record 10 of 11 |
| Author(s): Fang, C (Fang Cheng); Wang, ZG (Wang Zhi-Gang); Li, SS (Li Shu-Shen); Zhang, P (Zhang Ping) |
| Title: Orbital magnetization in semiconductors |
| Source: CHINESE PHYSICS B, 18 (12): 5431-5436 DEC 2009 |
| Abstract: This paper theoretically investigates the orbital magnetization of electron-doped (n-type) semiconductor heterostructures and of hole-doped (p-type) bulk semiconductors, which are respectively described by a two-dimensional electron/hole Hamiltonian with both the included Rashba spin-orbit coupling and Zeeman splitting terms. It is the Zeeman splitting, rather than the Rashba spin-orbit coupling, that destroys the time-reversal symmetry of the semiconductor systems and results in nontrivial orbital magnetization. The results show that the magnitude of the orbital magnetization per hole and the Hall conductance in the p-type bulk semiconductors are about 10(-2)-10(-1) effective Bohr magneton and 10(-1)-1 e(2)/h, respectively. However, the orbital magnetization per electron and the Hall conductance in the n-type semiconductor heterostructures are too small to be easily observed in experiment. |
| ISSN: 1674-1056 |
| Record 11 of 11 |
| Author(s): Gruter, RR (Grueter, R. R.); Khan, Z (Khan, Z.); Paxman, R (Paxman, R.); Ndieyira, JW (Ndieyira, J. W.); Dueck, B (Dueck, B.); Bircher, BA (Bircher, B. A.); Yang, JL (Yang, J. L.); Drechsler, U (Drechsler, U.); Despont, M (Despont, M.); McKendry, RA (McKendry, R. A.); Hoogenboom, BW (Hoogenboom, B. W.) |
| Title: Disentangling mechanical and mass effects on nanomechanical resonators |
| Source: APPLIED PHYSICS LETTERS, 96 (2): Art. No. 023113 JAN 11 2010 |
| Abstract: Micro and nanomechanical resonators are powerful and label-free sensors of analytes in various environments. Their response, however, is a convolution of mass, rigidity, and nanoscale heterogeneity of adsorbates. Here we demonstrate a procedure to disentangle this complex sensor response, to simultaneously measure both mass and elastic properties of nanometer thick samples. This turns an apparent disadvantage of these resonators into a striking and unique asset, enabling them to measure more than mass alone. |
| ISSN: 0003-6951 |
| Article Number: 023113 |
| DOI: 10.1063/1.3285169 |
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