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

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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.