Журнал материаловедения и инженерии

Theoretical Study of the Effect of an Fe Interlayer on the Formation of Graphene on a Diamond (111) Surface

Abstract

Yang Song and Karin Larsson

The effect by a catalytic Fe interlayer on the formation of graphene onto a diamond (111) substrate, has been studied by using DFT calculations under perodict boundary conditions. With varying the Fe interlayer thickness from two to five atomic layers, geometry optimized diamond//Fe//graphene multilayer models were obtained. A general result was that the Fe atoms are ontop positioned on both the graphene carbon atoms and on the diamond carbon atoms. Moreover, both the interfacial diamond//Fe and Fe//graphene adhesion energies were calculated and compared. As a result, the interaction between graphene and the iron layer, which was indentified as of an electrostatic nature, was found to be weak (-12.3 to -10.5 kJ/mol per graphene C atom) and propotional to the thickness of the Fe layer. The thicker the Fe interlayer, the stronger was the adhesion energy. On the contrary, the adhesion energy for the binding of a Fe layer on the diamond substrate was calculated as much stronger (-124.5 to -109.0 kJ/mol per diamond C atom), and following an inverse correlation. The thicker the Fe interlayer, the weaker is the interfacial adhesion energy. Calculations of electron density differences and partial Density of States (pDOS´s), will further support the results of a quantum size effect of the iron layer.