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本文探讨了在光折变晶体写入体相位栅产生高阶衍射的物理机制,在光栅的写入过程中,振幅和位相耦合分别引起光栅振幅和位相的不均匀,这两种不均匀性导致光栅波矢的附加横向分量,后者可有效地补偿高阶衍射的波矢失配,同时一旦高阶衍射在晶体表面出现,具有高增益值的光折变值晶体通过多波耦合将保证它随传播距离增长,这是在光折变晶体中形成高阶衍射光束的重要原因。 相似文献
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金属-半导体界面与肖特基势垒 总被引:1,自引:0,他引:1
本文主要评述关于肖特基势垒、半导体表面态和金属-半导体界面的实验研究和近年来的进展。第一部分介绍肖特基势垒的基本理论,实验方法和测量结果。第二部分介绍半导体表面态的实验研究,主要是用光电子能谱获得的成果。第三部分介绍近年来关于肖特基势垒和金属-半导体界面的一些研究进展。文中着重介绍美Stanford大学Spicer研究组的一系列贡献。 相似文献
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本文研究了贵金属-CaAs(110)界面形成过程中hν=21.2eV和40.8eV的价带光电子谱的演化,在小于0.5单原子层淀积金属时,观察到所谓原子样Ag5s和Au6s态。大约从10埃到几十埃的淀积金属范围内,发现贵金属价带发射极大值现象。用金属原子团的形成、岛状生长与界面反应相关的观点讨论了实验结果。
关键词: 相似文献
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We have investigated doped MBE GaAs films using photoreflectance (PR) spec-troscopy. Special spectral structures have been observed in the vicinity of the funda-mental band gap, which are quite different from the Franz-Keldysh oscillation (FKO) from uniform electric fields under flatband modulations. Numerical analysis has been performed for FKO from electric fields in the space charge region under non-flatband modulations. Some typical FKO line shapes are illustrated. For moderately doped samples the calculated line shapes are basically consistent with experiments. The surface electric field and the Fermi level pinning have also been deduced from exper-iments. 相似文献
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CoSi_2 薄膜的织构研究 总被引:2,自引:2,他引:0
对厚度约为0.4μm的CoSi2多晶薄膜的织构进行了研究。X射线极图分析表明,薄膜表现出与以往文献中所报导的CoSi2薄膜完全不同的织构类型。在Si(111)衬底上织构轴为[130],且平行于Si[111]。除[130]织构轴外,其它晶向亦有择优取向。 相似文献
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We have investigated the optical transitions above the fundamental gap of a set of GexSi1-x/Si strained layer multiple-quantum wells by electroreflectance (ER). The sam-ples were grown by molecular beam espitaxy (MBE). The thickness of the strained layer of GexSi1-x was 5nm with Ge concentration x in the range from 0.4 to 0.5, and the Si barrier layer greater than 16nm. Considering the energy shift caused by strain and quantum well confinement, we were able to clearly recognize the transitions from different quantum well structures associated with the critical points E0, E′0, and E1. The transitions of the critical points E0 and E′0, which are very weak in bulk mateials, are apparently enhanced in the quantum well structures. 相似文献
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本文报道在300和77K对一组具有不同垒宽Lb0.23Ga0.77As双量子阱样品的光调制反射谱(PR)的研究结果。除观察到11H,11L和22H等容许跃迁外,同时还识别一个从Al0.23Ga0.77As价带顶至量子阱第一电子束缚能级的跃迁,另一个从量子阱第一轻空穴束缚能级至Al0.23Ga0.77As导带底的跃迁。利用这些跃迁确定导带边不连续性为0.63。对Lb关键词: 相似文献
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We have investigated the optical transitions above the fundamental gap of a set of GexSi1-x/Si strained layer multiple-quantum wells by electroreflectance (ER). The sam-ples were grown by molecular beam espitaxy (MBE). The thickness of the strained layer of GexSi1-x was 5nm with Ge concentration x in the range from 0.4 to 0.5, and the Si barrier layer greater than 16nm. Considering the energy shift caused by strain and quantum well confinement, we were able to clearly recognize the transitions from different quantum well structures associated with the critical points E0, E′0, and E1. The transitions of the critical points E0 and E′0, which are very weak in bulk mateials, are apparently enhanced in the quantum well structures. 相似文献