外延

The relaxing ability of atoms in epilayer is also important in the formation of Moiré structure, which can be related to the bulk modulus of epilayer.

外延岛的面内弛豫行为与外延层和基体之间的相对刚度有关，弹性模量较大的外延层具有较强的延展能力，对Moir 结构的形成有利。

So, the biaxial strain is an important factor for the thickness effect in epitaxial manganite films, and it should be considered for fabricating a high quality of CMR films.

第四章以La_(0.7)Sr_(0.3)MnO_3外延薄膜为研究对象，研究了不同厚度的外延膜引起的外延膜电阻率的变化。

This project was established based on the first cooperative development of optical in situ real time detecting technique probing the atomic scale layer-by-layer epitaxy growth of oxide film. Over the last three years, we have given full play to the advantages and characteristics of both sides and have finished the assumptions and plans of this subject satisfactorily. 1. In Institute of Physics, we set up advanced oblique-incidence reflectivity difference equipment and wrote one data acquisition procedure that made the simultaneous detection of optical signal and RHEED signal into reality. 2. The first observation of sustained oscillations over hundreds of monolayers in both real and imaginary signals during the epitaxy growth of SrNb0.1Ti0.9O3 on SrTiO3 substrate in LMBE testifies that oblique-incidence is an excellent method to detect and monitor film epitaxy growth real time. 3. For the first time, we verify that oblique-incidence reflectivity difference method can be used to monitor the layer-by-layer growth mode during continuous growth through the correspondence between optical signals to atomic or molecular step edge density on the growth surface. 4. Phenomenological analysis shows that optical signals comprise three parts, the first is proportional to the average thickness of the film and depends on the bulk phase dielectric response; the second is proportional to the coverage of terraces and depends on the dielectric response of atoms or unit cells in the terrace; the third is proportional to the coverage of step edges and depends on the effective dielectric response of atoms or unit cells at step edges. This makes oblique-incident reflectivity difference technique a quantitative macroscopic method to monitor film growth.

中文摘要：本课题是在合作首次发展了氧化物薄膜原子尺度层状外延生长光学原位实时探测方法的基础上立项的，三年来，我们充分发挥双方的优势和特点，圆满完成了课题的设想和计划。1、在物理所建立了一套先进的光反射差法装置，编写了计算机系统的数据采集程序，实现了两路光学信号和RHEED数据的同步采集和显示。2、用激光分子束外延在SrTiO3基底上生长SrNb0.1Ti0.9O3薄膜，首次观测到连续外延几百个原胞层，周期振荡的光反射差实部和虚部信号，证明了光反射差法是一种能原位实时探测与监控薄膜层状外延生长的好方法。3、首次验证了通过对生长表面原子或分子台阶密度的响应，光反射差法可用于原位实时监测在连续生长条件下薄膜的层式生长模式。4、通过唯象理论的研究，证明光反射差信号由三项组成，第一项只与薄膜的平均厚度和宏观光学电介质常数有关；第二项与分子台阶面覆盖度和台阶面上分子层的光学电介质常数有关；第三项与台阶边缘的覆盖度成正比，并和在台阶边缘的分子的有效光学介电常数有关。

It is well known that the large lattice mismatch (16%) and thermal expansion coefficient mismatch between GaN and sapphire substrate are the main origins of TDs. By new growing technique of LEO, we acquired high quality GaN films almost free of TDs. The stress characteristics in GaN films with MLTB growing technique is dependent on growing systems and conditions, and the changes of stress and dislocation density are rightabout; Combining buffer layers of high temperature and low temperature is first developed to growing GaN films with low dislocation density, and the mechanism of lowering TDs density is that the first buffer layer of high temperature can make nuclear in second buffer layer of low temperature bigger. This technique also can restrain yellow luminescence effectively.

众所周知，晶格失配和热应力失配是GaN异质外延中位错产生的主要原因；为此，我们对几种降低缺陷的MOCVD外延生长方法进行了新的尝试，其中尝试了侧向外延生长技术，得到了低位错密度（小于10〓/cm〓）、高质量的GaN外延层；尝试多低温缓冲层法，发现材料中的应力特性与生长系统和生长条件有关，材料中的应力与位错密度按相反方向变化；首次尝试高低温联合缓冲层法，材料中高温缓冲层可以使随后的低温缓冲层中成核颗粒增大，从而导致随后高温GaN外延膜中位错密度降低，并且能够有效地抑制黄光峰。

The intensity ratio of TO and LO inMCT was observed to be different. Such difference was explained in terms of the different Ramangeometry arrangement.〓. The laser-induced micro-photoluminescence in the range of 1000～5000〓(1.34eV～1.83eV) was found for the first time in LPE MCT epilayer. The center of photoluminescence wasat 2750〓 or 1.62eV and the FWHM of luminescence was 2000〓 or 0.25eV. We assume thatthe photoluminescence is due to recombination of electron from an anion vacancy resonance levelto the top of valance. In addition, new Raman shift was observed at 750〓 in LPE MCTepitaxial film.〓. The laser-induced micro-photoluminescence with quasi-periodic structure was observed forthe first time at room temperature in one of MOVPE MCT epitaxial film samples. The range offluorescence was from 1.46eV to 2.21eV, i.e., 1.73eV above the conduction band edge.

2首次在LPE生长的碲镉汞外延薄膜的显微Raman谱中，在1000～5000〓范围发现了激光激发显微荧光，该荧光的发光范围换算为电子伏特标度为1.34eV～1.83eV，荧光的发光中心大约位于2750〓，即1.62eV，发光的半峰高宽约为2000〓或0.25eV；指出该显微荧光来源于碲镉汞薄膜中的阴性离子空位共振能级的激光激发发光；观察到了碲镉汞外延薄膜中一个新的Raman散射峰，位于750〓位置； 3首次在一块用MOVPE方法生长的〓Te外延薄膜的显微Raman谱中，发现了1.46eV至2.21eV范围并伴随有周期结构的显微荧光峰，该发光峰对应的能带中心位于〓Te材料导带底上方1.73eV，通过研究得出样品在1.46eV至2.21eV范围的显微荧光峰是由于改进 MOCVD 生长工艺，提高了碲镉汞外延薄膜的结构质量所致；通过分析指出该显微荧光来源于外延层中的阴性离子空位的共振能级发光。

We have epitaxially grown ultrathin Pb and Co films on the Cu(111)surface bymolecular beam exitaxialgrowth technique,and studied in detail the growthand surface alloying of submonolayer Pb on Cu(111),the shift of Pb 5d core levelbinding energy on Cu(111),the surfactant-assisted epitaxial growth of Co on Cu(111)using Pb as a surfactant,and the spin exchange splitting of ultrathin Co films onCu(111)using synchron radiation photoemission spectra as well as Auger electronspectraand low energy electron diffraction.

利用分子束外延生长技术在单晶Cu(111)表面外延生长了超薄Pb和Co膜，并利用同步辐射光电子发射谱，结合俄歇谱和低能电子衍射，详细研究了超薄Pb在Cu(111)表面的生长、表面合金化，Cu(111)表面Pb的5d芯能级位移，以Pb作活性剂时Co膜的活化外延生长，以及超薄Co在Cu(111)表面的自旋交换劈裂，得到了一些有意义的结果。

Based on the above investigation of ideal layer-by-layer growth process, the surface roughening phenomena during the real epitaxial growth are discussed. Some important microscopic dynamic models for molecular-beam epitaxy , which have attracted much attention recently, are studied. Using the master-equation method, the corresponding growth equations are directly derived, and then the scaling behaviors, the universalities, as well as the crossover effects are determined.

在这一理想层状外延生长研究的基础上对实际外延生长过程中十分显著的表面粗化现象进行了探讨，深入研究了几类近年来受到广泛关注的描述分子束外延生长的重要的微观动力学生长模型，采用主方程方法直接得到了相应的非线性生长方程，并确定了标度性质、普适类以及渡越行为。

Experimental results show that the film qualities are greatly affected by the ion-implantation temperature as well as the epitaxial annealing temperature.

通过实验系统地研究了离子注入过程中温度条件的控制对外延层质量的影响以及外延退火条件的选择与外延层结晶质量的关系。

It is shown that the results based on this approach are in good agreement with the accurate numerical results. The propagation characteristics of metal-clad exponential index distribution waveguide are analyzed, too.

在外延生长过程中，采用微欠饱和母液回熔方法，提高了外延生长的重复性，解决了较大面积外延生长的表面质量问题，回熔厚度可控制在1μm左右，回熔表面平均平整度在30—200nm之间。

The terrace widths and step densities increase with increasing the GaAs layer thickness and then saturates.

原子力显微镜测试表明：在常规分子束外延情况下，GaAs外延层台阶的厚度和台面的宽度随衬底温度的升高而增加，增加外延层厚度会导致台阶的密度和台面的宽度增加然后饱和。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。