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Underlying Layer (underlying + layer)

Distribution by Scientific Domains
Physics and Astronomy55%

Selected Abstracts

A combined imaging, microthermal and spectroscopic study of a multilayer packaging system

PACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2004
I. Woodward
Abstract The effectiveness of a packaging solution for the pharmaceutical and food industry is dependent on the integrity of the constituent layers and the interfaces formed between them. The deconvolution and analysis of the many intimate layers found in packaging is analytically challenging, requiring techniques capable of identifying sub-micron regions. Here we have characterized the chemical and physical nature of the layers in a multilayer packaging system along with the interfaces, using a combination of high-resolution atomic force microscopy (AFM), microthermal analysis using scanning thermal microscopy (SThM), and Fourier transform infrared (FT-IR) spectroscopy. In particular, localized thermal analysis is shown to reveal the thermal transitions of the individual layers, but it was found that care must be exercised when melting through one layer to the next, as this can result in overestimates of melting temperatures of the underlying layer due to excess power loss from the SThM probe to the already molten top layer surrounding the probe. Copyright © 2004 John Wiley & Sons, Ltd. [source]

High-performance UV emitter grown on high-crystalline-quality AlGaN underlying layer

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2009
Hirotoshi Tsuzuki
Abstract Al0.25Ga0.75N films were grown on a grooved-Al0.25Ga0.75N/ AlN/sapphire template by MOVPE. The dislocation density on the grooved areas was as low as 1 × 108 cm,2. We fabricated a UVA light-emitting diode grown on such an AlGaN underlying layer exhibiting an output power of 12 mW at a DC current of 50 mA with a peak emission wavelength of 345 nm, which corresponds to an external quantum efficiency of 6.7%. This efficiency is the highest reported to date in this wavelength region. We also fabricated a 358 nm UVA laser diode (LD) using a GaN/AlGaN MQW active layer grown on an AlGaN underlying layer. This UV LD exhibits a threshold current of 73 mA and a corresponding current density of 3.8 kA/cm2 at 7 °C. The characteristic temperature T0 was 174 K in the temperature range of 7,27 °C. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Improvement in crystalline quality of thick GaInN on m-plane 6H-SiC substrates using sidewall epitaxial lateral overgrowth

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008
Ryota Senda
Abstract We report the fabrication of an epitaxial lateral overgrown (ELO) GaInN layer on a high crystalline-quality-grooved GaN template, which is improved by a sidewall ELO (SELO) technology. The photoluminescence peak intensity of ELO-grown GaInN layer on the SELO GaN underlying layer is twice as high as that of ELO-grown GaInN layer on the m-plane GaN template. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optimization of underlying layer and the device structure for group-III-nitride-based UV emitters on sapphire

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
K. Iida
Abstract Epitaxial lateral overgrowth (ELO) was applied for the growth of AlGaN on a sapphire substrate by metalorganic vapor phase epitaxy. Among several processes, the ELO of AlGaN on grooved AlGaN showed the best surface morphology and the lowest dark-spot density of 1×108 cm,2 as measured using cathodoluminescence. The light output power of a UV LED fabricated on ELO-Al0.25Ga0.75N on grooved Al0.25Ga0.75N was the strongest among several UV LEDs fabricated by different processes. The effect of the Al composition in the electron-blocking (EB) layer on the performance of UV LEDs was investigated. The UV LED with a low-Al-content EB layer showed high output power under a low-injection condition, while the output power of a UV LED with a high-Al-content EB layer did not saturate even under a high-injection condition. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fast simulation of skin sliding

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 2-3 2009
Xiaosong Yang
Abstract Skin sliding is the phenomenon of the skin moving over underlying layers of fat, muscle and bone. Due to the complex interconnections between these separate layers and their differing elasticity properties, it is difficult to model and expensive to compute. We present a novel method to simulate this phenomenon at real-time by remeshing the surface based on a parameter space resampling. In order to evaluate the surface parametrization, we borrow a technique from structural engineering known as the force density method (FDM)which solves for an energy minimizing form with a sparse linear system. Our method creates a realistic approximation of skin sliding in real-time, reducing texture distortions in the region of the deformation. In addition it is flexible, simple to use, and can be incorporated into any animation pipeline. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The formation and sedimentary infilling of the Cave of Hearths and Historic Cave complex, Makapansgat, South Africa

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2004
A.G. Latham
The archaeology of caves is best served by including a study of natural effects prior to and during anthropogenic input. This is especially true for the Cave of Hearths because not only has erosion determined the area of occupation, but also subsequent undermining has caused collapse of some of the rearward parts of the site during Early Stone Age (Acheulian) and later times; and this had a major impact on excavation. The key to understanding the nature of the collapsed layers was the rediscovery of a lower part of the cavern below the whole site. This lower cavern is no longer accessible, but the evidence for it was revealed in a swallow hole by R.J. Mason, and in archived material at the Department of Archaeology, University of Witwatersrand. The creation and dissolution of dolomite fragments in the upper layers has resulted in the formation of thick, carbonate-cemented breccia that has preserved underlying layers and prevented further collapse. We agree with Mason that further archaeological and hominid finds await excavation under the proximate Historical Cave west entrance. This area has the potential for archaeological and palaeoanthropological material that predates the layers in the Cave of Hearths. © 2004 Wiley Periodicals, Inc. [source]

Direct Laser Writing of Nanoscale Light-Emitting Diodes

ADVANCED MATERIALS, Issue 29 2010
Oleg Makarovsky
Nanoscale light-emitting diodes (nanoLEDs) and arrays of nanoLEDs produced by laser controlled diffusion of interstitial manganese (Mni) donor ions out of the ferromagnetic semiconductor (GaMn)As towards the underlying layers of a quantum well heterostructure. The approach represents an alternative to deep etching for the creation of nanoscale current channels and nanoLEDs. [source]

Ultrathin metal layers to convert surface polarity of nitride semiconductors

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2005
T. Nakayama
Abstract The possibility of the surface-polarity conversion of AlN upon the deposition of ultrathin Al metal layers is investigated by the first-principles theoretical calculations. It is shown that, reflecting the crystal structures of underlying layers and the binding-energy difference between Al,N and Al,Al bonds, the surface-polarity conversion from N-face to Al-face polarity becomes possible only when the deposited Al metal layers have wurtzite structure and two-monolayer thickness. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]