Growth of graphene/Ge/Si heterostructure on Si(0 0 1) substrate.

Graphene/Ge/Si heterostructure were fabricated on Si(1 0 0) by direct transfer method. The monolayer graphene was transferred onto Ge/Si epilayer with the Raman intensity ratio (I 2D /I G ) of 1.75. The defect related D peak located at 1346 cm −1 is also very weak, signified the small amount of defects. Raman spectroscopy confirmed single crystal Ge film with S-K growth mode was obtained. The lattice mismatch between Ge and Si causes 0.8° off axis of Ge film. The growth mode of Ge film also confirmed as S-K mode when the growth temperature is higher than 650 °C, which cause a lower shift of Ge Raman shift peak. [ABSTRACT FROM AUTHOR]