Graphene grown on Ge(0 0 1) from atomic source

Abstract Among the many anticipated applications of graphene, some – such as transistors for Si microelectronics – would greatly benefit from the possibility to deposit graphene directly on a semiconductor grown on a Si wafer. We report that Ge(0 0 1) layers on Si(0 0 1) wafers can be uniformly covered with graphene at temperatures between 800 °C and the melting temperature of Ge. The graphene is closed, with sheet resistivity strongly decreasing with growth temperature, weakly decreasing with the amount of deposited C, and reaching down to 2 k Ω / □ . Density functional theory calculations indicate that the major physical processes affecting the growth are (1) substitution of surface Ge by C, (2) interaction between C clusters and Ge monomers, and (3) formation of bonds between graphene edge and Ge(0 0 1), and that the processes 1 and 2 are surpassed by CH 2 surface diffusion when carbon is delivered from CH 4 . The results of this study indicate that graphene can be produced directly at the active region of the transistor in a process compatible with the Si technology.