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901.
Dong Ho Kim Su Jin Kim Seung Hwan Kim Tak Jeong Sung Min Hwang Tae Geun Kim 《固体物理学:研究快报》2011,5(8):274-276
The authors report upon the increased light‐output power (Pout) via a reduction in the forward voltage (Vf) for nonpolar a ‐plane GaN LEDs using Ni/Al/Ni/Au n‐type ohmic contacts. The specific contact resistivity of the Ni/Al/Ni/Au contact is found to be as low as 5.6 × 10–5 whereas that of a typical Ti/Al/Ni/Au contact is 6.8 × 10–4 Ω cm2, after annealing at 700 °C. The X‐ray photoelectron spectroscopy results show that the upward surface band bending is less pronounced for the Ni/Al contact compared to the Ti/Al contact, leading to a decrease in the effective Schottky barrier height (SBH). The Vf of the nonpolar LEDs decreases by 10% and Pout increases by 15% when the Ni/Al/Ni/Au scheme is used instead of the typical Ti/Al/Ni/Au metal scheme. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
902.
Bin Xia Yu WuHui Wen Ho Chang KeWen Dong Song Cheng Hon Alfred HuanJer Lai Kuo Wei Guang ZhuLan Wang 《Physica B: Condensed Matter》2011,406(17):3166-3169
Room temperature ferromagnetism in both transition-metals doped and undoped semiconductor thin films and nanostructures challenges our understanding of the magnetism in solids. In this report, we performed the magnetic measurement and Andreev reflection spectroscopy study on undoped Indium-Tin oxide (ITO) thin films and bulk samples. The magnetic measurement results of thin films show that the total magnetization/cm2 is thickness independent. Prominent ferromagnetism signal was also discovered in bulk samples. Spin polarized electron transports were probed on ITO thin film/superconductor interface and bulk samples surface/superconductor interface. Based on the magnetic measurement results and spin polarization measurement data, we propose that the ferromagnetism in this material originates from the surface spin polarization and this surface polarization may also explain the room temperature ferromagnetism discovered in other undoped oxide semiconductor thin films and nanostructures. 相似文献
903.
An experimental and simulation investigation regarding the effect of various CRAMPS parameters (delays interleaved with the decoupling shape, z-rotation symmetry and offset frequency) on the DUMBO decoupling performance is presented using two model compounds, glycine and tyrosine·HCl. Although the conclusions of this work may be extended to the other homonuclear-decoupling schemes, this work focuses essentially on the effect of adding interleaved delays to DUMBO decoupling during the indirect dimension using different 2D pulse-scheme architectures. While the simulations revealed an increasing loss of the spectral resolution with longer delays (from 0 to 6 μs), the experimental 2D (1)H DUMBO NMR correlation spectra revealed that the inclusion of delays, during the indirect dimension, improves the (1)H resolution whether the z-rotation symmetry was used or not. The best experimental spectra are obtained when z-rotation symmetry and windows are combined. 相似文献
904.
We report FDTD simulation results demonstrating that the optical phase change of surface plasmon polariton-assisted transmission
through nanohole arrays in a metal film undergoes a sharp change under resonant conditions. The phenomenon can be explained
by various resonant modes between the nanoholes. We further explore the possibility of using this effect for phase-sensitive
surface plasmon resonance biosensing applications. 相似文献
905.
Min Hwan Lee Kyung Min Kim Seul Ji Song Sang Ho Rha Jun Yeong Seok Ji Sim Jung Gun Hwan Kim Jung Ho Yoon Cheol Seong Hwang 《Applied Physics A: Materials Science & Processing》2011,102(4):827-834
The bipolar resistive switching mechanisms of a p-type NiO film and n-type TiO2 film were examined using local probe-based measurements. Scanning probe-based current–voltage (I–V) sweeps and surface potential/current maps obtained after the application of dc bias suggested that resistive switching is
caused mainly by the surface redox reactions involving oxygen ions at the tip/oxide interface. This explanation can be applied
generally to both p-type and n-type conducting resistive switching films. The contribution of oxygen migration to resistive
switching was also observed indirectly, but only in the cases where the tip was in (quasi-) Ohmic contact with the oxide. 相似文献
906.
We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions. Unlike the Hadamard transform, a well-known data acquisition method that is used only for conventional multichannel rotating-element ellipsometers with line arrays with specific readout-mode timing, this Fourier analysis is applicable to various line arrays with either nonoverlap or overlap readout-mode timing. To assess the effects of the novel Fourier analysis, the Fourier coefficients for a sample were measured with a custom-built rotating-polarizer ellipsometer, using this Fourier analysis with various numbers of scans, integration times, and rotational speeds of the polarizer. 相似文献
907.
Francisco Eduardo de Sousa Filho João Hermínio da Silva Antônio Álamo Feitosa Saraiva Deyvid Dennys S. Brito Bartolomeu Cruz Viana Bruno Tavares de Oliveira Abagaro Paulo de Tarso Cavalcante Freire 《Brazilian Journal of Physics》2011,41(4-6):275-280
X-ray diffraction was combined with X-ray energy-dispersion, Fourier-transform infrared, and Raman spectroscopies to study the fossilization of a Cretaceous specimen of the plant Brachyphyllum castilhoi, a fossil from the Ipubi Formation, in the Araripe Sedimentary Basin, Northeastern Brazil. Among the possible fossilization processes, which could involve pyrite, silicon oxide, calcium oxide, or other minerals, we were able to single out pyritization as the central mechanism producing the fossil, more than 100 million years ago. In addition to expanding the knowledge of the Ipubi Formation, this study shows that, when combined with other experimental techniques, Raman spectroscopy is a valuable tool at the paleontologist’s disposal. 相似文献
908.
N. MurisicJ. Ho V. HuP. Latterman T. KochK. Lin M. MataA.L. Bertozzi 《Physica D: Nonlinear Phenomena》2011,240(20):1661-1673
Particle settling in driven viscous films is a complex physical process involving different physical effects. A recent analysis by Cook (2008) [10] has identified a balance between hindered settling and shear-induced migration as the dominant large scale physics for particle/liquid separation. However, experimental data for this has been lacking. This paper presents new data including the role of particle size and liquid viscosity showing clear agreement with the theory. We discuss the role of timescales in the dynamics of the experiment and present results from a dynamic model. 相似文献
909.
Seok-Jun Won 《Applied Surface Science》2011,257(23):10311-10313
The reaction of Bis(ethyl-methyl-amino)silane (BEMAS) and water in atomic layer deposition (ALD) became possible when Zr-containing species were adsorbed on the vacant sites of the surface after a pulse and purge of BEMAS. The growth rates of the Si(Zr)Ox films were 0.8-0.9 nm/cycle in the temperature range of 185-325 °C. This phenomenon probably originates from the highly reactive hydroxyl species generated by Zr atoms. From this point of view, transition metals make reactant gas molecules to be highly activated in the ALD processes of transition metal oxides and nitrides, which might be an important factor that determines the ALD characteristics. 相似文献
910.
Trade credit financing plays a vital role in current business operations. Vendors extend payment dates to encourage sales, and buyers are not required to pay immediately after receiving products. This is equivalent to receiving a price reduction. Besides, buyers reduce their need for capital from bank loans. In addition, a number of defective products are produced during the production process. The number of defective items influences the on-hand inventory levels of buyers, service levels, and frequency of orders. To ensure that the analysis incorporates a realistic production environment, we developed an integrated inventory model with a two-part trade credit and considered an imperfect production process that can be improved by capital investment. The objective was to determine the optimal ordering, shipping, and quality improvement policies to maximize joint total profit. An iterative algorithm was established to determine the optimal strategy. Furthermore, a sensitivity analysis was conducted to examine the effects of changing parameter values on the optimal solution. 相似文献