The effect of the SiC(0001) surface morphology on the growth of epitaxial monolayer graphene nanoribbons

Graphene nanoribbons (GNRs) are promising for applications in nanoelectronics due to their unique properties including an electronic band gap which is inversely proportional to their width. Therefore, achieving a controlled and high-quality synthesis of GNRs is anticipated to be of great importance. One of the methods which show great potential is the epitaxial growth of GNRs at step edge regions of SiC surfaces, due to the control it offers over the dimension of the GNRs. In addition, the transfer to other substrates is not required in the case of electronic applications.

Figure – SEM image from mono-layer GNRs (darker contrast) grown at 1450 °C on low-miscut SiC substrate (top). An Arrhenius plot of the rate of lateral expansion of mono-layer GNRs versus growth temperature. The activation energies obtained (Ea) are given. The existence of two activation energies for the growth of GNRs on high-miscut SiC surfaces is related to the formation of few-layer thick graphene at the step facets (bottom).

In this contribution we report on the controlled growth and structural characterization of epitaxial monolayer GNRs on SiC(0001) surfaces, which were prepared by utilizing the surface graphitization method at high temperatures. By controlling the time and temperature in the furnace, it is possible to vary the width of the monolayer GNRs. We studied the influence of growth temperature and SiC substrate miscut angle (or initial step height) on the GNR width, establishing a correlation between step heights and ribbon width. While a linear growth rate best describes the growth for lower step heights, a nonlinear rate is observed for substrates with higher steps, which is also associated with the formation of few-layer graphene on the step edges.

1 Author L. A. Galves , J. M. Wofford , G. V. Soares , U. Jahn , C. Pfüller , H. Riechert , J. M. J. Lopes

The effect of the SiC(0001) surface morphology on the growth of epitaxial mono-layer graphene nanoribbons

Source Carbon , 115 , 162 ( 2017 )
DOI : 10.1016/j.carbon.2017.01.018 | 2869 Cite : Bibtex RIS
L. A. Galves, J. M. Wofford, G. V. Soares, U. Jahn, C. Pfüller, H. Riechert, and J. M. J. Lopes