537 resultados para InAs nanostructures
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Anodic bonding with thin films of metal or alloy as an intermediate layer, finds increasing applications in micro/nanoelectromechanical systems. At the bonding temperature of 350 degrees C, voltage of 400 V, and 30 min duration, the anodic bonding is completed between Pyrex glass and crystalline silicon coated with an aluminum thin film with a thickness comprised between 50 and 230 nm. Sodium-depleted layers and dendritic nanostructures were observed in Pyrex 7740 glass adjacent to the bonding interface. The sodium depletion width does not increase remarkably with the thickness of aluminum film. The dendritic nanostructures result from aluminum diffusion into the Pyrex glass. This experimental research is expected to enhance the understanding of how the depletion layer and dendritic nanostructures affect the quality of anodic bonding. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
A theoretical model is presented to investigate the size-dependent elastic moduli of nanostructures with the effects of the surface relaxation surface energy taken into consideration. At nanoscale, due to the large ratios of the surface-to-volume, the surface effects, which include surface relaxation surface energy, etc., can play important roles. Thus, the elastic moduli of nanostructures become surface- and size-dependent. In the research, the three-dimensional continuum model of the nanofilm with the surface effects is investigated. The analytical expressions of five nonzero elastic moduli of the nanofilm are derived, and then the dependence of the elastic moduli is discussed on the surface effects and the characteristic dimensions of nanofilms.
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This paper reports self-organized nanostructures observed on the surface of ZnO crystal after irradiation by a focused beam of a femtosecond Ti:sapphire laser with a repetition rate of 250 kHz. For a linearly polarized femtosecond laser, the periodic nanograting structure on the ablation crater surface was promoted. The period of self-organization structures is about 180 nm. The grating orientation is adjusted by the laser polarization direction. A long range Bragg-like grating is formed by moving the sample at a speed of 10 mu m/s. For a circularly polarized laser beam, uniform spherical nanoparticles were formed as a result of Coulomb explosion during the interaction of near-infrared laser with ZnO crystal.
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Two-dimensional periodic nanostructures on ZnO crystal surface were fabricated by two-beam interference of 790 nm femtosecond laser. The long period is, as usually reported, determined by the interference pattern of two laser beams. Surprisingly, there is another short periodic nanostructures with periods of 220-270 nm embedding in the long periodic structures. We studied the periods, orientation, and the evolution of the short periodic nanostructures, and found them analogous to the self-organized nanostructures induced by single fs laser beam. (C) 2008 Optical Society of America.
Resumo:
An approach for fabricating large area uniform nanostructures by direct femtosecond (fs) laser ablation is presented. By the simple scanning technique with appropriate irradiation conditions, arbitrary size of uniform, complanate nano-grating, nano-particle, and nano-square structures can be produced on wide bandgap materials as well as graphite. The feature sizes of the formed nanostructures, which can be tuned in a wide range by varying the irradiation wavelength, is about 200 nm with 800 nm fs laser irradiation. The physical properties of the nano-structured surfaces are changed greatly, especially the optical property, which is demonstrated by the extraordinary enhancement of light transmission of the treated area. This technique is efficient, universal, and environmentally friendly, which exhibits great potential for applications in photoelectron devices. (C) 2008 Optical Society of America
Resumo:
In this paper, we report the laser-induced periodic structure with different spatial characteristics on the surface of polished ZnO single-crystalline by high repetition rate femtosecond laser pulses. This study demonstrates that, using different laser parameters and irradiation conditions, ZnO nanoripples and nanorods were successfully prepared. We have investigated the surface by means of scanning electron microscope (SEM), Raman scattering and photoluminescence (PL). We propose that second-order harmonic has a strong influence on the formation of nanostructures. (c) 2007 Elsevier B.V All rights reserved.
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z
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Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z