RUI: The Interdependence of GaN Surface Chemistry and Surface Morphology and Reconstruction

这个RUI项目解决了GaN表面的化学性质，以及这些反应如何受到表面形态（簇覆盖或光滑）的影响，以及相反地，表面形态如何通过反应进行修改。GaN上的簇形成似乎特别容易，并且与原子级光滑表面相比，预期会导致富Ga表面。表面反应，pre-age集群的形成以及蚀刻反应将是拟议的研究的重点。表面反应将通过使用紫外光电子能谱的表面电子结构的变化和通过确定分子从表面解吸的温度来监测。将使用扫描隧道显微镜和低能电子衍射表征表面形态。实验将确定表面形态如何影响化学，通过在表面反应之前制备具有已知形态的表面。表面化学如何改变形态将通过在表面反应后重新检查GaN表面来表征，以评估局部表面结构或组成如何改变。还将通过紫外线和X射线光电子能谱法评估组成和电子密度的变化。通过比较已知形态变化的表面，可以通过光电子能谱确定表面是光滑的还是簇覆盖的。%该项目涉及具有技术相关性的材料科学专题领域的基础研究问题。本科生将在该项目中发挥主要作用，研究机会直接融入他们的学术课程。UW-Eau Claire化学和物理学院之间新建立的合作增强了该项目。最近通过NSF MRI奖获得的instrumentation已被合并为一个通用材料研究设施，其中来自几个团体和部门的教师和学生作为一个团队在各种研究项目上工作。这种跨学科的材料研究方法提供了一个环境，本科生直接与同龄人合作，发展合作学习技能，并指导经验不足的学生。该研究计划使前沿研究和获得最先进的表面科学设备的本科生。***

This RUI project addresses the chemistry of GaN surfaces and how these reactions are influenced by surface morphology (cluster-covered or smooth), and conversely how surface morphology is modified by reactions. Cluster formation on GaN appears to be especially facile, and is expected to result in Ga-rich surfaces compared to atomically smooth surfaces. Surface reactions that pres-age cluster formation as well as etching reactions will be the focus of the proposed research. Sur-face reactions will be monitored by changes in surface electronic structure using ultraviolet pho-toelectron spectroscopy and by determining the temperature at which molecules desorb from the surface. Surface morphology will be characterized using scanning tunneling microscopy and low-energy electron diffraction. Experiments will determine how surface morphology influences chemistry by preparing a surface with known morphology before surface reactions. How surface chemistry changes morphology will be characterized by re-examining the GaN surface after sur-face reactions to assess how local surface structure or composition has changed. Changes in composition and electron density will also be evaluated by ultraviolet and X-ray photoelectron spectroscopy. By comparing surfaces with known changes in morphology, it may be possible to establish whether a surface is smooth or cluster-covered by photoelectron spectroscopy.%%% The project addresses fundamental research issues in a topical area of materials science having technological relevance. Undergraduate students will play a primary role in the project, with op-portunities for research integrated directly into their academic program. A newly established collaboration between UW-Eau Claire chemistry and physics faculty enhances the project. In-strumentation recently acquired through NSF MRI awards has been combined into a common-use materials research facility in which faculty and students from several groups and departments work as a team on various research projects. This interdisciplinary approach to materials research provides an environment where undergraduate students work directly with their peers, and de-velop cooperative learning skills as well as mentoring less-experienced students. The research program enables forefront research and access to state-of-the-art surface science equipment to undergraduate students. ***