Perfecting Monolayer Graphene by Defect Removal Using Novel Thermo-Mechanical Methods

最近的实验表明，单层碳原子石墨烯在室温下表现出惊人的高电子迁移率。当基于硅的技术达到基础物理施加的自然极限时，这种非凡的电子行为很可能使纳米电子技术取得突破性进展。然而，对石墨烯质量的控制仍然是一个重大挑战，因为即使是少数几个原子缺陷也可能显著降低石墨烯设备的性能。该研究小组寻求开发一种新的热机械方法，通过集成的实验和建模工作有效地消除缺陷，从而完善石墨烯薄板。特别是，将开发时间加速模拟方法来确定热和机械载荷下的缺陷迁移势垒和路径以及缺陷-缺陷反应机理。同时，将在热机械处理前后对悬浮单层石墨烯器件的拉曼形貌、电输运和低温磁输运进行实验测量，目的是验证建模方法和评估方法的有效性。为完善石墨烯薄片而开发的新的热机械方法有望在实现基于石墨烯的下一代电子学方面取得重大突破。该项目还将有助于推动在分析和处理石墨烯以及其他纳米材料中的缺陷方面取得变革性的进展。将研究成果与连续介质力学理论相结合，将建立热机械载荷与缺陷迁移率之间的本构关系，这对改进现有的石墨烯制备工艺和设计超越石墨烯的未来材料体系具有重要意义。在教育方面，拟议的研究将在大学和K-12阶段创造许多机会。宾夕法尼亚州立大学的研究生和本科生将从创新、综合实验操纵和计算纳米力学的多学科研究经验中受益匪浅。PIS将积极与宾夕法尼亚州立大学的几个组织合作，让代表人数不足的群体，包括妇女和少数族裔学生，参与实施拟议的研究计划。

Recent experiments have demonstrated that graphene, a monolayer of carbon atoms, exhibits surprisingly high room-temperature electron mobility. Such a remarkable electronic behavior may well enable ground-breaking advances in nanoelectronics when silicon-based technologies reach their natural limits imposed by fundamental physics. However, the control over the quality of graphene remains a major challenge because even a few atomic defects may markedly degrade the performance of a graphene device. The research team seeks to develop a novel thermo-mechanical method for perfecting graphene sheets by effectively removing defects through an integrated experimental and modeling effort. In particular, time-accelerated modeling methods will be developed to determine defect migration barriers and pathways and defect-defect reaction mechanisms under thermal and mechanical loadings. In parallel, experimental measurements of Raman topography, electrical transport, and low-temperature magnetotransport of suspended monolayer graphene devices will be performed before and after thermo-mechanical treatments, aiming at validating the modeling approaches and evaluating the effectiveness of the methods. The novel thermo-mechanical methods developed for perfecting graphene sheets are expected to lead to major breakthroughs toward realization of the graphene-based next-generation electronics. The project will also help foster transformative progress for the analysis and manipulation of defects in graphene as well as other nano-materials in general. When combined with continuum mechanics theories, the research results will establish new constitutive equations relating thermo-mechanical loading with defect mobility, which will be valuable for improving existing graphene manufacturing processes and for designing future materials systems beyond graphene. On the educational front, the proposed research will generate many opportunities at both the college and K-12 levels. Graduate and undergraduate students at Penn State will benefit greatly from the multidisciplinary research experience in innovative, integrated experimental manipulation and computational nano-mechanics. The PIs will actively work with several organizations at Penn State to involve underrepresented groups including women and minority students in carrying out proposed research program.