检索结果-内蒙古大学图书馆

Temperature dependence of the quantum efficiency in green light emitting diode dies

physica status solidi c 2007年第7期4卷

作者： Y. Li W. Zhao Y. Xia M. Zhu J. Senawiratne T. Detchprohm E. F. Schubert C. Wetzel Department of Physics Applied Physics and Astronomy Rensselaer Troy NY 12180 USA Future Chips Constellation Rensselaer Polytechnic Institute Troy NY 12180 USA Department of Electrical Computer and Systems Engineering Rensselaer Troy NY 12180 USA

The electroluminescence of GaInN/GaN multiple quantum well light-emitting diode dies is analyzed at variable low temperatures. We compare the external quantum efficiency of three dies of nominally identical structure but strongly different RT performance at 520 nm. For all dies, the external quantum efficiency increases as the temperature is lowered. A maximum is reached for all near 158 K while for lower temperatures as low as 7.7 K, the efficiency continuously drops. The low-temperature efficiency is the lowest for the highest performing die at RT. The peak energy exhibits a blue shift from RT to 158 K followed by a red shift for lower temperatures. In the same low-temperature range, a secondary emission peak appears near 390 nm that resembles a donor-acceptor pair transition. The pronounced efficiency maximum is tentatively assigned to competition of carrier transport properties and the non-radiative lifetime in the active region. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

关键词： 73.40.Kp 73.61.Ey 78.60.Hk 78.67.De 85.60.Jb

来源：评论

学校读者我要写书评

暂无评论

Erratum: “Kinetic study of Al-mole fraction in AlxGa1−xN grown on c-plane sapphire and AlN bulk substrates by metal-organic vapor-phase epitaxy” [Appl. Phys. Lett. 90, 051104 (2007)]

引用

applied physics Letters 2007年第20期90卷

作者： Y. A. Xi K. X. Chen F. W. Mont J. K. Kim W. Lee E. F. Schubert W. Liu X. Li J. A. Smart Future Chips Constellation Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 Future Chips Constellation Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy New York 12180 Future Chips Constellation Department of Material Science and Engineering Rensselaer Polytechnic Institute Troy New York 12180 Future Chips Constellation Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 and Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy New York 12180 Crystal IS Inc. Green Island New York 12183

In a recent publication,1 we analyzed and modeled the Al mole fraction in AlxGa1−xN as a function of the TMAl and TMGa volume and molar flow during epitaxial gr

关键词：

来源：评论

学校读者我要写书评

暂无评论

Quantum Effects of Mesoscopic Inductance and Capacity Coupling Circuits

引用

Communications in Theoretical physics 2006年第6期45卷 1126-1130页

作者： LIU Jian-Xin AN Zhan-Yuan SONG Yong-Hua Department of Electrical Engineering North China Electric Power University Baoding 071003 China Department of Applied Physics North China Electric Power University Baoding 071003 China Electronic and Computer Engineering Department Brunel University London UK

Using the quantum theory for a mesoscopic circuit based on the discretenes of electric charges, the finitedifference Schrodinger equation of the non-dlssipative mesoscopic inductance and capacity coupling circuit is achieved. The Coulomb blockade effect, which is caused by the discreteness of electric charges, is studied. Appropriately choose the components in the circuits, the finlte-dlfference Schrodinger equation can be divided into two Mathieu equations in representation.＂ With the WKBJ method, the currents quantum fluctuations in the ground states of the two circuits are calculated. The results show that the currents quantum zero-point fluctuations of the two circuits are exist and correlated.

关键词： mesoscopic circuit Mathieu equation quantum effect

来源：评论

学校读者我要写书评

暂无评论

Zero-n¯ bandgap in photonic crystal superlattices

引用

Journal of the Optical Society of America B: Optical physics 2006年第3期23卷 506-513页

作者： Panoiu, Nicolae C. Osgood Jr., Richard M. Zhang, Shuang Brueck, Steven R.J. Department of Applied Physics and Applied Mathematics Columbia University New York NY 10027 United States Center for High Technology Materials Department of Electrical and Computer Engineering University of New Mexico Albuquerque NM 87106 United States

We demonstrate that photonic superlattices consisting of a periodic distribution of layers of materials with positive index of refraction and photonic crystal slabs that, at the operating frequency, have negative effective index of refraction present a photonic gap that corresponds to the frequency at which the spatial average of the refractive index distribution, taken over the unit supercell of the superlattice, vanishes. We also show that, unlike the Bragg gaps, the frequency of this zero-n¯ gap is invariant to the geometrical scaling of the superlattice or the direction of wave propagation in the superlattice. © 2006 Optical Society of America.

关键词： Optical materials

来源：评论

学校读者我要写书评

暂无评论

Energy Spectra of a Magnetic Quantum Ring with an Off-Center Impurity

引用

Communications in Theoretical physics 2006年第4期45卷 737-740页

作者： LEE Chak-Man LI Jun-Qin RUAN Wen-Ying Richard LEE Chak-Hong Department of Material Science and Engineering Shenzhen University Shenzhen 518060 China Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign Urbana IL61801 USA Department of Applied Physics South China University of Technology Guangzhou 510641 China

In this paper, we calculate the low-lying spectra of a single-electron magnetic quantum ring with an offcenter Coulomb impurity, where the magnetic field is zero within the ring and constant elsewhere. The impurity, either an acceptor or a donor, is located at a distance d as measured from the plane of the ring along the vertical z direction. The magnetic moments are found in order to get visible discontinuities at the points of the ground-state orbital angular momentum L transitions induced by magnetic fields.

关键词： magnetic quantum ring Meissner effect magnetic moment

来源：评论

学校读者我要写书评

暂无评论

Guest editorial nonlinear optimization of communication systems

引用

IEEE Journal on Selected Areas in Communications 2006年第8期24卷 1421-1423页

作者： Chiang, Mung Low, Steven H. Luo, Zhi-Quan Shroff, Ness B. Yu, Wei Steenstrup, M. Princeton University Department of Electrical Engineering Program in Applied and Computational Mathematics Princeton NJ 08544 United States California Institute of Technology Department of Computer Science Pasadena CA 91125 United States University of Minnesota Department of Electrical and Computer Engineering Minneapolis MN 55455 United States Purdue University School of Electrical and Computer Engineering West Lafayette IN 47907 United States University of Toronto Edward S. Rogers Sr. Department of Electrical and Computer Engineering Toronto Ont. M4S 3G5 Canada

No abstract available

关键词： Communication systems Design optimization Communication system control Optimization methods Protocols Distributed algorithms Power system modeling Nonlinear control systems Lagrangian functions Surges

来源：评论

学校读者我要写书评

暂无评论

Workshop on imaging science development for cancer prevention and preemption

引用

Cancer Biomarkers 2007年第1期3卷 1-33页

作者： Kelloff, Gary J. Sullivan, Daniel C. Baker, Houston Clarke, Lawrence P. Nordstrom, Robert Tatum, James L. Dorfman, Gary S. Jacobs, Paula Berg, Christine D. Pomper, Martin G. Birrer, Michael J. Tempero, Margaret Higley, Howard R. Petty, Brenda Gumbs Sigman, Caroline C. Maley, Carlo Sharma, Prateek Wax, Adam Ginsberg, Gregory G. Dannenberg, Andrew J. Hawk, Ernest T. Messing, Edward M. Grossman, H. Barton Harisinghani, Mukesh Bigio, Irving J. Griebel, Donna Henson, Donald E. Fabian, Carol J. Ferrara, Katherine Fantini, Sergio Schnall, Mitchell D. Zujewski, Jo Anne Hayes, Wendy Klein, Eric A. DeMarzo, Angelo Ocak, Iclal Ketterling, Jeffrey A. Tempany, Clare Shtern, Faina Parnes, Howard L. Gomez, Jorge Srivastava, Sudhir Szabo, Eva Lam, Stephen Seibel, Eric J. Massion, Pierre McLennan, Geoffrey Cleary, Kevin Suh, Robert Burt, Randall W. Pfeiffer, Ruth M. Hoffman, John M. Roy, Hemant K. Wang, Thomas Limburg, Paul J. El-Deiry, Wafik S. Papadimitrakopoulou, Vali Hittelman, Walter N. MacAulay, Calum Veltri, Robert W. Solomonzz, Diane Jeronimo, Jose Richards-Kortum, Rebecca Johnson, Karen A. Viner, Jaye L. Stratton, Steven P. Rajadhyaksha, Milind Dhawan, Atam NIH/NCI/DCTD Cancer Imaging Program Bethesda MD United States NIH/NCI/DCTD Cancer Imaging Program NCI-Frederick Frederick MD United States NIH/NCI/DCP Early Detection Research Group Bethesda MD United States The Johns Hopkins University School of Medicine Departments of Radiology Pharmacology and Oncology Division of Neuroradiology Baltimore MD United States NIH/NCI/CCR Cell and Cancer Biology Branch Bethesda MD United States University of California San Francisco Department of Medicine Division of Medical Oncology San Francisco CA United States CCS Associates Inc. Mountain View CA United States Wistar Institute Molecular and Cellular Oncogenesis Program Philadelphia PA United States University of Kansas School of Medicine VA Hospital Kansas City MO United States Duke University Department of Biomedical Engineering Medical Physics Program Durham NC United States University of Pennsylvania School of Medicine Department of Gastroenterology Philadelphia PA United States New York Presbyterian Hospital Weill Medical College of Cornell University New York NY United States NIH/NCI/OD Office of Centers for Training and Resources Bethesda MD United States University of Rochester Medical Center Department of Urology Rochester NY United States University of Texas MD Anderson Cancer Center Department of Urology Houston TX United States Massachusetts General Hospital Abdominal Imaging/Interventional Radiology Boston MA United States Boston University Biomedical Engineering Electrical and Computer Engineering and Physics Boston MA United States NIH/NCI/DCP Gastrointestinal and Other Cancers Research Group Bethesda MD United States The George Washington University Cancer Institute Office of Cancer Prevention and Control Washington DC United States University of Kansas Cancer Center Clinical Oncology Kansas City KS United States University of California Davis Department of Biomedical Engineering Davis CA United States Tufts University De

The concept of intraepithelial neoplasm (IEN) as a near-obligate precursor of cancers has generated opportunities to examine drug or device intervention strategies that may reverse or retard the sometimes lengthy process of carcinogenesis. Chemopreventive agents with high therapeutic indices, well-monitored for efficacy and safety, are greatly needed, as is development of less invasive or minimally disruptive visualization and assessment methods to safely screen nominally healthy but at-risk patients, often for extended periods of time and at repeated intervals. Imaging devices, alone or in combination with anticancer drugs, may also provide novel interventions to treat or prevent precancer.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Saturated 13.2 nm high repetition rate laser in nickel-like Cd and isoelectronic scaling down to 10.9 nm

Saturated 13.2 nm high repetition rate laser in nickel-like ...

引用

Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006

作者： Luther, B.M. Wang, Y. Larotonda, M.A. Alessi, D. Berrill, M. Shlyaptsev, V.N. Rocca, J.J. NSF ERC for Extreme Ultraviolet Science and Technology Electrical and Computer Engineering Department Colorado State University Applied Physics Department University of California Davis

A table-top λ=13.2nm soft x-ray laser operating at 5 Hertz repetition rate with 1W average power was demonstrated in Ni-like Cd. Lasing down to 10.9 nm was also obtained in transitions of other Ni-like ions. © 2... 详细信息

ISBN: (纸本)1557528136

关键词： Nickel

来源：评论

学校读者我要写书评

暂无评论

Plasmon-induced magnetization of periodic nanohole arrays

Plasmon-induced magnetization of periodic nanohole arrays

引用

Conference on Lasers and Electro-Optics, CLEO 2006

作者： Smolyaninov, I.I. Davis, C.C. Smolyaninova, V.N. Schaefer, D. Elliott, J. Zayats, A.V. Department of Electrical and Computer Engineering University of Maryland United States Department of Physics Astronomy and Geosciences Towson University Towson MD United States Department of Pure and Applied Physics Queen's University of Belfast United Kingdom

Plasmon-induced magnetism of periodic nanohole arrays has been studied using transmission spectroscopy and magnetic-force microscopy. This second-order nonlinear optical effect can find numerous applications in magnet... 详细信息

ISBN: (纸本)1557528136

关键词： Optical data storage

来源：评论

学校读者我要写书评

暂无评论

Reduction of base access resistance in AlGaN/GaN heterojunction bipolar transistors using GaInN base cap layer and selective epitaxial growth

引用

2005 Materials Research Society Fall Meeting

作者： Shah, Jay M. Gessmann, Thomas Luo, Hong Xi, Yangang Chen, Kaixuan Kim, Jong Kyu Fred Schubert, E. Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY 12180-3590 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy NY 12180-3590 United States

ISBN: (纸本)1558998462

One of the major challenges affecting the performance of Npn AlGaN/GaN heterojunction bipolar transistors (HBTs) is the high base access resistance, which is comprised of the base contact resistance and the base bulk resistance. A novel concept is proposed to reduce the base access resistance in Npn AlGaN/GaN HBTs by employing polarization-enhanced contacts and selective epitaxial growth of the base and emitter. In addition, this technique reduces the exposed base surface area, which results in a lower surface recombination current. Such a structure would enable better performance of AlGaN/GaN HBTs in terms of higher current gain and a lower offset voltage. Theoretical calculations on polarization-enhanced contacts predict p-type specific contact resistance lower than 10-55 Ωcm2. Experimental-results using transmission line measurement (TLM) technique yield specific contact resistances of 5.6×10-4 Ωcm2 for polarization-enhanced p-type contacts and 7.8×10-2 Ωcm2 for conventional p-type contacts. © 2006 Materials Research Society.

关键词： Heterojunction bipolar transistors

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：