X-ray Physics and Heteroepitaxy

该项目致力于表面x射线散射研究 在完美的晶体衬底上外延生长。 的一部分 努力将致力于推广的确切结果， 动态衍射理论，表面衍射，补充 基于运动学理论的电流描述。 测量 将在洁净的硅和锗表面上以超高 使用三重晶体衍射（TCD）方法在真空中进行。 然后，实验将继续与单层覆盖的晶格- 匹配的碱金属卤化物外延生长到Ge表面上， TCD和X射线驻波（XSW）测量均用于 解决“阶段性问题”。“研究亦会扩展至 更厚的碱金属卤化物层，部分是为了监控 干涉之间的基板和覆盖层衍射在 XSW和TCD光谱。 这种反射高能的x射线类似物 对电子衍射振荡进行了理论分析 使用适当的计算模型。

This project is devoted to surface x-ray scattering studies of epitaxial growth onto perfect crystal substrates. Part of the effort will be devoted to an extension of exact results of dynamical diffraction theory to surface diffraction, to complement current descriptions based on kinematical theory. Measurements will be made on clean silicon and germanium surfaces in ultra-high vacuum using the triple crystal diffraction (TCD) method. Experiments will then proceed with monolayer coverages of lattice- matched alkali halides epitaxially grown onto Ge surfaces, with both TCD and x-ray standing wave (XSW) measurements being used to solve the "phase problem." The studies will also be extended to thicker layers of alkali halides, in part to monitor the interference between the substrate and overlayer diffraction in the XSW and TCD spectra. This x-ray analog of reflection high energy electron diffraction oscillations will be analyzed theoretically using appropriate computational models.