Nucleation and Growth of Epitaxial Graphene Formed by Physical Vapor Deposition

技术：本项目主要研究单层石墨烯和固体源分子束外延（MBE）形成的石墨烯基异质结构的生长和性能。通过MBE可以很好地控制碳沉积速率，使薄膜能够在广泛的动力学条件下生长，同时消除与碳前驱体化学有关的影响，这些影响在常用的化学气相沉积工艺中自然存在。该研究受到最近在铜箔上生长石墨烯的研究的启发，这些研究表明石墨烯岛核是在该系统中获得原始石墨烯的最终瓶颈。该项目以这些结果为基础，研究了导致受控石墨烯成核的条件，并探索了石墨烯边缘原子和底物附着原子之间的关键相互作用，这在岛进化中起着关键作用。利用低能电子显微镜对石墨烯在不同衬底上的生长进行实验，有望对衬底结构、晶格错配、衬底阶梯流动和界面相互作用的作用提供基本的见解。此外，MBE将用于在超高真空条件下形成石墨烯-介电双层，这将通过电学，结构和光学测量进一步研究。非技术：该项目涉及材料科学主题领域的基础研究问题，具有高技术相关性。分子束外延在石墨烯生长中的应用，将这种先进的沉积技术的广泛能力带入了石墨烯科学技术的范畴。如果项目成功，新的功能和增强的性能将通过石墨烯和其他材料之间的原始界面的形成而出现。一项教育计划与研究相结合，汇集了来自不同高等教育水平的新兴学者，从社区学院到研究生院，以研究石墨烯。外展项目活动的中心是将原始研究概念融入到本科生和社区大学生的暑期体验中，这些学生来自传统上未被充分代表的科学和工程群体。夏季对石墨烯的研究将作为实验室教学模块的测试平台，这些模块将在高级的顶点实验课程中实施。

Technical: This project is on the growth and properties of monolayer graphene and graphene based heterostructures formed by solid-source molecular beam epitaxy (MBE). The well-controlled carbon deposition rates made possible by MBE enable the growth of films under a wide range of kinetic conditions while removing effects related to carbon precursor chemistry, which exist naturally in the commonly used chemical vapor deposition processes. The research is inspired by recent studies of graphene grown on copper foils, which show graphene island nucleation as the ultimate bottleneck to achieving pristine graphene in this system. The project, building on these results, investigates the conditions that lead to controlled graphene nucleation and probes the critical interactions between graphene edge atoms and substrate adatoms, which play a key role in island evolution. Experiments of graphene growth on different substrates by low-energy electron microscopy is expected to provide fundamental insight into the roles of substrate texture, lattice mismatch, substrate stepflow, and interfacial interactions. In addition, MBE will be used to form graphene-dielectric bilayers under ultrahigh vacuum conditions, which will be studied further via electrical, structural and optical measurements.Nontechnical: The project addresses basic research issues in a topical area of materials science with high technological relevance. The application of molecular beam epitaxy to graphene growth brings the extensive capabilities of this advanced deposition technique into the fold of graphene science and technology. If the project is successful, new functionalities and enhanced properties can emerge through the formation of pristine interfaces between graphene and other materials. An education plan is integrated with the research and brings together emerging scholars from across different levels of higher education, community college to graduate school, for the study of graphene. Outreach project activities center on the integration of original research concepts into summer experiences for undergraduates and community college students from traditionally underrepresented groups in science and engineering. Summer investigations on graphene will serve as test beds for lab instructional modules that will be implemented in a senior-level, capstone laboratory course.