Titanium-carbide formation at defective curved graphene-titanium interfaces

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOPhysical and chemical properties of graphene-metal interfaces have been largely examined with the objective of producing nanostructured carbon-based electronic devices. Although electronic properties are key to such devices, appropriate structural, thermal and mechanical properties are important for device performance as well. One of the most studied is the graphene-titanium (G-Ti) interface. Titanium is a low density, high strength versatile metal that can form alloys with desirable properties for applications ranging from aerospace to medicine. Small clusters and thin films of titanium deposited on graphene have also been examined. However, while some experiments show that thin films of titanium on graphene can be removed without damaging graphene hexagonal structure, others reported the formation of titanium-carbide (TiC) at G-Ti interfaces. In a previous work [ACS Appl. Mater. Interfaces, 2017, 9 (38), pp 33288-33297], we have shown that pristine G-Ti interfaces are resilient to large thermal fluctuations even when G-Ti structures lie on curved or kinked substrates. Here, using classical molecular dynamics with the third-generation Charge Optimized Many Body (COMB3) potential, we show that di-interstitial defective G-Ti structures on a copper substrate with a relatively large curvature kink, present signs of TiC formation. This result might help explain the different experimental results mentioned above.38/9454459CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO302750/2015-02016/00023-9A.F.F. is a fellow of the Brazilian Agency CNPq (#302750/2015-0) and acknowledges grant #2016/00023-9 from Sao Paulo Research Foundation (FAPESP) and from FAEPEX/UNICAMP. This research also used the computing resources and assistance of the John David Rogers Computing Center (CCJDR) in the Institute of Physics "Gleb Wataghin", University of Campinas. T.L., D.Z., K.C. and S.B.S. were supported by UNCAGE-ME, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0012577