超晶格中直流和双模交流电场的整流效应

以弛豫时间近似下的玻尔兹曼方程为基础，详细研究了超晶格在外加直流和双模交流场中电子的输运行为，并计算了几种特定情况下超晶格中电流随频率和场强幅值的变化关系，我们发现超晶格在外加直流和双模交流电流电场时内部电流随频率的变化是稳定的，而电流随场强幅值的变化是振荡衰减的。     

ZnSe-ZnS超晶格的量子尺寸效应

本文报导了我们用常压MOCVD生长的ZnSe-ZnS应变超晶格的发光特性。我们首次制备了阱宽低达10(?)的ZnSe-ZnS应变超晶格。     

超晶格中的电子谱

对多年来超晶格多量子阱中的电子谱滤波及相关研究成果进行了总结、归纳，并研究了纳米面材料的电子滤波，超晶格多量子阱中的电子谱．叙述了周期超晶格和非周期超晶格中的电子透射和反射系数，介绍了外场下超晶格中的电子谱．外界条件可引起超晶格中内建电场的变化，进而引起隧穿电流的变化．     

超晶格中内建电场的压力调制

目的 研究超晶格中内建电场随着压力（压强）的变化规律。方法 针对沿任意方向生长的立方晶系超晶格材料，讨论其内应变随着外加压力的变化关系，进一步讨论内建电场随着压力的变化规律。结果与结论 针对三种不同材料组合的超晶格，给出了内建电场随压力的变化曲线图。在一定范围内，内建电场随着压力呈近似线性关系。     

超晶格中的电子谱

对多年来超晶格多量子阱中的电子谱滤波及相关研究成果进行了总结、归纳,并研究了纳米面材料的电子滤波,超晶格多量子阱中的电子谱.叙述了周期超晶格和非周期超晶格中的电子透射和反射系数,介绍了外场下超晶格中的电子谱.外界条件可引起超晶格中内建电场的变化,进而引起隧穿电流的变化.     

侧向半导体反铁磁/非磁超晶格的色散性质

应用等效介质理论,研究由反铁磁半导体和绝缘非磁物质构成的侧向半无限反铁磁/非磁超晶格的色散性质,以及外加磁场和涡流对色散曲线的影响.     

硅锗超晶格结构热导率的分子动力学模拟

采用Stillinger-Webber势能函数描述硅锗超晶格结构原子间的相互作用,建立硅锗超晶格结构的热传导系统,利用非平衡分子动力学模拟方法计算了不同周期数、不同厚度、不同温度下的Si/Ge超晶格结构热导率.模拟结果表明：超晶格结构热导率随着周期长度和周期数的增加而逐渐增大.受界面热阻效应的影响,靠近高温热墙处导热层...     

超晶格中内建电场的压力调制

目的　研究超晶格中内建电场随着压力 (压强 )的变化规律 .方法　针对沿任意方向生长的立方晶系超晶格材料 ,讨论其内应变随着外加压力的变化关系 ,进一步讨论内建电场随着压力的变化规律 .结果与结论　针对三种不同材料组合的超晶格 ,给出了内建电场随压力的变化曲线图 .在一定范围内 ,内建电场随着压力呈近似线性关系     

锗／硅短周期超晶格的X射线双晶衍射研究

用X射线双晶衍射对气源分子束外延(GS-MBE)制备的锗／硅短周期超晶格(SPS)样品进行了分析．所有样品的锗层厚度固定为1．5单原子层,而硅层厚度为1．4～3．8nm．对于硅层厚度小于2．4nm的样品来说,双晶衍射摇摆曲线中由超晶格引起的衍射峰较宽,而且看不到干涉引起的精细结构,这表明超晶格中可能存在位错及界面不平整．对硅层较厚(＞2．9nm)的样品,摇摆曲线中超晶格引起的衍射峰很窄,而且有明显的由干涉产生的精细结构,表明此时超晶格的质量较高,界面平整．对硅层厚度为2．1～2．9nm的样品,超晶格对应的衍射峰可以分解为两个宽度不等的子峰,但没有精细结构出现．这个区间与文献[1]报道的在荧光光谱发现的一个异常带出现区间完全相同．本实验的X射线双晶衍射测试与分析结果支持文献[1]提出的此异常带与局部应力场引起的外延层呈波浪状扭曲有关的结论。     

应力对LaAlO3/BaTiO3超晶格结构及性能的影响

采用激光脉冲分子束外延技术,在(100)取向SrTiO3或Nb:SrTiO3单晶基片上成功外延生长不同结构的LaAlO3/BaTiO3超晶格。利用高能电子衍射技术和X射线衍射技术对LaAlO3/BaTiO3超晶格的生长过程和微结构进行了表征。发现由于LaAlO3和BaTiO3晶格常数的不匹配,在LaAlO3/BaTiO3超晶格中存在应变,该应变又对超晶格的铁电性能具有很大的影响。而不同的结构存在的应变不同,非对称结构的LaAlO3/BaTiO3超晶格的应变随每个周期中LaAlO3层厚度的增加、BaTiO3层厚度的减少而增大,其剩余极化强度不仅未减少,反而增加。     

Structural and optical characteristics of Al_xGa_(1-x)N/AlN superlattice

AlN/Al0.3Ga0.7N superlattices were grown on (0001) sapphire substrate by metal-organic chemical vapor deposition (MOCVD). The superlattice period varies from 6 to 30. The layer thickness of different period stack was designed. GaN or AlGaN template was employed for growing AlN/AlGaN superlattices. Reflectivity, SEM, AFM and XRD data of the AlxGa1-xN/AlN superlattices are presented. It is found that the templates used have an intensive impact on surface roughness and interfacial properties of following AlN/AlGaN superlattices. The result of atomic force microscopy indicates that AlN/AlGaN superlattices grown on GaN template exhibit quasi-two-dimensional growth mode. The resulting superlattice has a smooth surface morphology and distinct interface. No crack is observed in the area of a 2-inch wafer.     

Structural and optical characteristics of Al x Ga1- x N/AlN superlattice

AlN/Al_0.3Ga_0.7N superlattices were grown on (0001) sapphire substrate by metal-organic chemical vapor deposition (MOCVD). The superlattice period varies from 6 to 30. The layer thickness of different period stack was designed. GaN or AlGaN template was employed for growing AlN/AlGaN superlattices. Reflectivity, SEM, AFM and XRD data of the Al _x Ga_1-x N/AlN superlattices are presented. It is found that the templates used have an intensive impact on surface roughness and interfacial properties of following AlN/AlGaN superlattices. The result of atomic force microscopy indicates that AlN/AlGaN superlattices grown on GaN template exhibit quasi-two-dimensional growth mode. The resulting superlattice has a smooth surface morphology and distinct interface. No crack is observed in the area of a 2-inch wafer. Supported by the Special Funds for Major State Basic Research Project (973 Project) (Grant No. 2006CB6049), the Hi-tech Research Project (Grant Nos. 2006AA03A103, 2006AA03A118, and 2006AA03A142), the National Natural Science Foundation of China (Grant No. 60676057), and the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20050284004)     

纳米级人工超晶格多层膜的X射线广角衍射分析

作者导出人工超晶格多层膜的X射线衍射的几何光学图，得出多层膜的Bragg方程，并讨论因装放样品而导致样品的轴偏心的精细误差消除步骤，用普通广角X射线衍射仪，在低角区得到纳米级单、多层膜的调幅波长（厚度）及周期。     

Epitaxial growth of Fe/Ag single crystal superlattices and their magnetic properties

Single crystal Fe/Ag(001) superlattices with various periodicities were fabricated using ultrahigh vacuum evaporation de-position.It was found that single crystal bcc Fe layers and single crystal fcc Ag layers can epitaxially grow on a single crystal Ag buffer layer alternately,which was deposited on NaCl single crystal chips by ion beam assisted deposition.The magnetic measure-ments of the superlattices reveal an oscillation coupling between ferromagnetism and antiferromagnetism as a function of the Ag layer thickness.The oscillation period,which is 1 nm (5 Ag layers),is in good agreement with the calculated values when the Ag thickness is greater than 1.5 nm.While the thickness of the Ag spacer layer decreases to 1 nm,the oscillation coupling varies from calculations,which can be attributed to the intermixing of the interlayers according to the annealing results.     

局域场关联和二维体系的不稳定性

本文采用ＳＴＬＳ方法对超晶格的局域场关联和稳态结构因子进行了讨论。并在赫伯德近似下得到了局域场关联ＧＨ（Ｋ，ＫＺ）的表示式。探讨了超晶格等离子激元的色散和电荷密度波的不稳定性，且给出了稳定性区域的判据。     

Comparison of short period InAs/GaSb superlattices on GaSb and GaAs substrates

Type II superlattices (SLs) short period InAs(4ML)/GaSb(8ML) were grown by molecular-beam epitaxy on lattice-mismatched GaAs substrates and on GaSb substrates. A smooth GaSb epilayer was formed on GaAs substrates by inserting mulit-buffer layers including an interfacial misfit mode AlSb quantum dot layer and AlSb/GaSb superlattices smooth layer. SLs grown on GaAs substrates (GaAs-based SLs) showed well-resolved satellite peaks in XRD. GaSb-based SLs with better structural quality and smoother surface showed strong photoluminescence at 2.55 μm with a full width at half maximum (FWHM) of 20 meV, narrower than 31 meV of GaAs-based SLs. Inferior optical absorption of GaAs-based SL was observed in the range of 2―3 μm. Photoresponse of GaSb-based SLs showed the cut-off wavelength at 2.6 μm.     

（ZnSe）n／（ZnS）m应变层超晶格的光吸收系数

用Ｌｕｔｔｉｎｇ┐Ｋｏｈｎ有效质量理论研究了［０，０，１］方向生长的（ＺｎＳｅ）ｎ／（ＺｎＳ）ｍ应变层超晶格的光吸收系数，并与前人实验结果比较和讨论．结果表明：光吸收系数与阱宽和垒宽有关