Chemical Vapor Deposition Growth of Graphene on 200 mm Ge(110)/Si Wafers and Ab Initio Analysis of Differences in Growth Mechanisms on Ge(110) and Ge(001)

For the fabrication of modern graphene devices, uniformgrowthof high-quality monolayer graphene on wafer scale is important. Thiswork reports on the growth of large-scale graphene on semiconducting8 inch Ge(110)/Si wafers by chemical vapor deposition and a DFT analysisof the growth process. Good graphene quality is indicated by the smallFWHM (32 cm(-1)) of the Raman 2D band, low intensityratio of the Raman D and G bands (0.06), and homogeneous SEM imagesand is confirmed by Hall measurements: high mobility (2700 cm(2)/Vs) and low sheet resistance (800 & omega;/sq). In contrastto Ge(001), Ge(110) does not undergo faceting during the growth. Weargue that Ge(001) roughens as a result of vacancy accumulation atpinned steps, easy motion of bonded graphene edges across (107) facets,and low energy cost to expand Ge area by surface vicinals, but onGe(110), these mechanisms do not work due to different surface geometriesand complex reconstruction.