共查询到20条相似文献,搜索用时 453 毫秒
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一、半导体超晶格和量子阱 最近十几年来,在半导体材料、物理、器件研究的领域中半导体超晶格和量子阱的研究十分活跃。可以这样说,这方面的研究是整个半导体领域中最大、最有前途、内容最丰富的一个生长点。 什么是超晶格?众所周知,晶态固体内的原子是周期性排列的。如果用人工控制的办法能够使材料的结构以原周期的若干倍周期性地变化,这样得到的材料就叫做超晶格。目前研究得最多的超晶格材料是交替生长两种半导体薄层多次而形成的.如在一块衬底材料上生长。个原子层的A半导体(例如 GaAs),再生长 n个原子层的B半导体(例如 Gal.xAI人s,… 相似文献
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文章扼要介绍了2004年国家自然科学二等奖获奖项目:《若干低维材料的拉曼光谱学研究》.用拉曼光谱研究低维纳米材料,必须对传统拉曼光谱学进行改造,创建新的“低维拉曼光谱学”.该项目通过若干低维材料的研究,为创建低维拉曼光谱学作出了系统的创新性贡献,如最先鉴认出典型低维材料的拉曼指纹谱,发现拉曼光谱的两个基本特征出现“反常”,但证明拉曼散射基本原理在低维体系中依然成立.通过低维拉曼光谱和光发射谱的应用研究,发现了材料的许多新奇物性,如发现超晶格和碳纳米管是类缺陷结构,和极性半导体纳米晶材料具有非晶特性,并提出了多孔硅的“量子限制电化学”形成和“多源量子阱”光发射模型,促进了低维材料和半导体器件的制备. 相似文献
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中科院半导体所云集着黄昆、林兰英等一流物理学家和一大批有作为的中青年学者,他们在半导体物理,特别是在半导体超晶格物理的理论研究、半导体超晶格的光谱物理、超晶格低维系统的输运特性、超晶格量子阱中杂质、深能级行为、超晶格、多层异质结构材料诸方面获得众多成果,在世界半导体物理领域占有重要地位.根据灰色文献的定义,我们将该所学者在国际会议报告和将发表的论文有选择地摘录发表.供广大读者参考. 相似文献
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超晶格材料是用现代薄膜生长技术制成的一种新型材料,它在过去的自然界中从未存在过,是一种完全新的人工制造的晶体. 1970年,美国IBM公司的江崎玲于奈(L.Esaki)和朱兆祥首次在GaAs半导体上制成了超晶格结构[1].以后,半导体超晶格的研究工作得到了很快的发展,不仅研制出GaAs和各种Ⅲ-V族化合物超晶格材料,而且Ⅳ-Ⅳ族、Ⅱ-Ⅵ族、Si超晶格以及非晶态半导体超晶格等也已相继出现,有一些已经获得实用,做成了相当重要的微电子和光电子器件.半导体超晶格以及与之相联系的异质结中的许多物理现象,特别是低维物理现象已引起了人们广泛的兴趣.近… 相似文献
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用超球坐标方法研究在弱磁场中的二维D-中心 总被引:1,自引:0,他引:1
将超球坐标数值计算近似方法引入半导体中的低维量子系统,求解了二维D^-中心在弱磁场中的薛定谔方程,得到了二维D^-中心的基态和低激发态的体系能,计算得到的基态能与变分法得到的结果及实验结果均获得较好的一致。 相似文献
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P. Malý 《Czechoslovak Journal of Physics》2002,52(5):645-667
A large amount of work has been worldwide directed to understand the properties of semiconductor nanostructures. Ultrafast
lasers with pulsewidths of a few femtoseconds allowed the investigation of the dynamics of elementary excitations in semiconductor
structures on ultrashort time scales. Recent progress in technology made it possible to fabricate semiconductor nanocrystals
(i.e. crystals of nanometer dimensions) of well-defined properties. The purpose of this paper is to review the understanding
of carrier relaxation and recombination processes in semiconductor nanocrystals as studied by ultrafast laser spectroscopy.
The up-to-date techniques of ultrafast laser spectroscopy as well as the fabrication of semiconductor nanocrystals are discussed
in some detail. 相似文献
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飞秒物理、飞秒化学和飞秒生物学 总被引:7,自引:0,他引:7
飞秒激光技术因其极高的时间分辨特性而被广泛应用于研究多种材料的超快过程,文章从几个侧面就飞秒技术在物理学,化学及生物学等方面的应用作了介绍,在飞秒物理方面,介绍了飞秒技术在研究半导体量子阱材料,纳米材料的性质及高次谐波产生等方面的研究进展,飞秒化学则主要介绍了飞秒技术在研究光化学反应,光解离过程、键的断裂及结合以及相关的动力学过程的应用;在生物方面,则介绍利用飞秒技术研究光合作用中的能量传递过程,视觉系统中的光致异构化过程以及DNA中的电荷传递及质子传递等过程的研究现状。 相似文献
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《Laser \u0026amp; Photonics Reviews》2014,8(2):250-250
Femtosecond‐laser micromachining has been developed as one of the most efficient techniques for direct three‐dimensional microfabrication of transparent optical materials. In integrated photonics, by using direct writing of femtosecond/ultrafast laser pulses, optical waveguides can be produced in a wide variety of optical materials. With diverse parameters, the formed waveguides may possess different configurations. The paper by F. Chen and J.R. Vázquez de Aldana (pp. 251–275) focuses on crystalline dielectric materials, and is a review of the state‐of‐the‐art in fabrication, characterization and applications of femtosecond‐laser micromachined waveguiding structures in optical crystals and ceramics. 相似文献
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Dorchies F Lévy A Goyon C Combis P Descamps D Fourment C Harmand M Hulin S Leguay PM Petit S Peyrusse O Santos JJ 《Physical review letters》2011,107(24):245006
X-ray absorption near-edge spectroscopy (XANES) is a powerful probe of electronic and atomic structures in various media, ranging from molecules to condensed matter. We show how ultrafast time resolution opens new possibilities to investigate highly nonequilibrium states of matter including phase transitions. Based on a tabletop laser-plasma ultrafast x-ray source, we have performed a time-resolved (~3 ps) XANES experiment that reveals the evolution of an aluminum foil at the atomic level, when undergoing ultrafast laser heating and ablation. X-ray absorption spectra highlight an ultrafast transition from the crystalline solid to the disordered liquid followed by a progressive transition of the delocalized valence electronic structure (metal) down to localized atomic orbitals (nonmetal-vapor), as the average distance between atoms increases. 相似文献
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Kamiya T. Tsuchiya M. Miyamoto M. Lee J. Tanaka T. Sasaki S. 《Optical and Quantum Electronics》2000,32(4-5):443-452
Ultrashort laser pulses offer new jump in information and communication technology. Especially semiconductor laser based ultrafast photonic devices and systems are promising. We review our new approaches for femtosecond pulse generation, and thin film technology for broad band semiconductor optical amplifiers. 相似文献
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随着超快激光技术的发展及其人们对太赫兹(THz)电磁波波段与脉冲光源认识的进一步深入,太赫兹时域光谱(THz-TDS)技术作为一种新的、快速发展的光谱分析方法在许多领域备受关注。利用太赫兹时域光谱技术在空气环境下测量样品时,样品的太赫兹光谱会因空气中水蒸气的影响而出现振荡现象。文章利用太赫兹时域光谱分析技术分别在氮气和空气环境下测量了七种样品在0.2~1.9太赫兹波段的光谱,并以氮气环境下的太赫兹光谱为参考,利用小波变换对空气环境下测量的数据进行了处理,消除了太赫兹光谱中水蒸气吸收造成的影响,实验结果证明了该方法的可行性,在此基础上,还对其中四种样品做了成像和识别,并得到了较好的结果。 相似文献
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S. Lauzurica J.J. García-BallesterosM. Colina I. Sánchez-AniorteC. Molpeceres 《Applied Surface Science》2011,257(12):5230-5236
Monolithical series connection of silicon thin-film solar cells modules performed by laser scribing plays a very important role in the entire production of these devices. In the current laser process interconnection the two last steps are developed for a configuration of modules where the glass is essential as transparent substrate. In addition, the change of wavelength in the employed laser sources is sometimes enforced due to the nature of the different materials of the multilayer structure which make up the device. The aim of this work is to characterize the laser patterning involved in the monolithic interconnection process in a different configurations of processing than the usually performed with visible laser sources. To carry out this study, we use nanosecond and picosecond laser sources working at 355 nm of wavelength in order to achieve the selective ablation of the material from the film side. To assess this selective removal of material has been used EDX (energy dispersive using X-ray) analysis, electrical measurements and confocal profiles. In order to evaluate the damage in the silicon layer, Raman spectroscopy has been used for the last laser process step. Raman spectra gives information about the heat affected zone in the amorphous silicon structure through the crystalline fraction calculation. The use of ultrafast sources, such as picoseconds lasers, coupled with UV wavelength gives the possibility to consider materials and substrates different than currently used, making the process more efficient and easy to implement in production lines. This approach with UV laser sources working from the film side offers no restriction in the choice of materials which make up the devices and the possibility to opt for opaque substrates. 相似文献