贵金属—GaAs(110)界面价带紫外光电子谱

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：     

金属-半导体界面与肖特基势垒

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。     

FRANZ-KELDYSH OSCILLATION FROM THE SPACE CHARGE REGION OF MBE GaAs FILMS

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.     

GaAs/Al0.23Ga0.77As双量子阱的带边不连续性和阱间耦合

本文报道在300和77K对一组具有不同垒宽L_b0.23Ga_0.77As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Al_0.23Ga_0.77As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Al_0.23Ga_0.77As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L_{b关键词：}     

光折变晶体中的稳态光扇

指出在高增益的光折变晶体内光束自身的多波混合是光扇形成的一个可能起因．通过光束自身的多波耦合作用，光能从低空间频率成分转移至高频成分上，从而形成宽角分布的扇形轮廓，所以放大噪声和放大光束中高频成分在光扇效应中都起重要的作用． 关键词：     

ELECTROREFLECTANCE SPECTRA OF GexSi1-x/Si STRAINED LAYER MULTIPLE-QUANTUM WELLS

We have investigated the optical transitions above the fundamental gap of a set of Ge_xSi_1-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 Ge_xSi_1-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.     

ELECTROREFLECTANCE SPECTRA OF GexSi1-x/Si STRAINED LAYER MULTIPLE-QUANTUM WELLS

We have investigated the optical transitions above the fundamental gap of a set of Ge_xSi_1-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 Ge_xSi_1-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.     

肖特基势垒形成的研究

金属-半导体接触的整流性质是一个古老的固体物理问题.它的发现可追溯到1874年Braun对金属-硫化铜接触的导电性质的研究.Schottky(肖特基)最早系统地研究了金属-半导体接触,他指出,接触的整流性质是来自接触附近半导体内形成的势垒.后来,人们常把金属-半导体接触形成的势垒称为肖特基势垒. 关于肖特基势垒形成的理论,最早由Scho-ttky,Mott等人提出.1947年 Bardeen把半导体表面电子态的概念引入这个理论中.从此这个传统的理论被学术界广泛地接受,成为半导体物理教科书的重要内容[1].由于表面电子态是固体物理学中一个非常重要的课题,以及门…     

光折变多量子阱光学寻址空间光调制器的理论分析

利用瞬态二维输运模型,给出了半绝缘多量子阱光学寻址空间光调制器在纵向场几何的理论分析.建立了空间电荷场分量的偏微分方程和边值方程,并通过数值方法进行了求解.在推导方程中考虑了双极、各向异性输运和带边共振激发等因素.结果表明,在小光栅间距下横向场显著影响体电荷的分布,体电荷的分布效应又强烈影响器件的分辨率和时间响应. 关键词：     

SIN+ GaAs结构中的Franz-Keldysh振荡的傅里叶变换研究

利用傅里叶变换(FT)方法,对Franz-Keldysh振荡(FKO)的理论线性作了详细的数值模拟,并 用光调制反射谱(PR)测量了一组本征层(I层)厚度不同的表面-本征层-n型重掺杂层(SIN⁺)结构的GaAs样品的FKO. PR谱的FT分析表明,一部分样品的FT谱,包括其实部、虚 部和模,与理论线性符合得比较好,由此求出轻空穴(LH)和重空穴(HH)的约化质量平方根之 比μ_l/μ_h对不同样品在0805—0816之间,同时也可以求出 关键词： Franz-Keldysh振荡 傅里叶变换 GaAs