Accession Number : AD1015571


Title :   Electronic and Mechanical Properties of GrapheneGermanium Interfaces Grown by Chemical Vapor Deposition


Descriptive Note : Journal Article


Corporate Author : Northwestern University Evanston United States


Personal Author(s) : Kiraly,Brian ; Jacobberger,Robert M ; Mannix,Andrew J ; Campbell,Gavin P ; Bedzyk,Michael J ; Arnold,Michael S ; Hersam,Mark C ; Guisinger,Nathan P ; Kiraly,Brian ; Jacobberger,Robert M ; Mannix,Andrew J ; Campbell,Gavin P ; Bedzyk,Michael J ; Arnold,Michael S ; Hersam,Mark C ; Guisinger,Nathan P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1015571.pdf


Report Date : 27 Oct 2015


Pagination or Media Count : 7


Abstract : Epitaxially oriented wafer-scale graphene growndirectly on semiconducting Ge substrates is of high interest forboth fundamental science and electronic device applications. Todate, however, this material system remains relatively unexploredstructurally and electronically, particularly at the atomic scale. Tofurther understand the nature of the interface between graphene andGe, we utilize ultrahigh vacuum scanning tunneling microscopy(STM) and scanning tunneling spectroscopy (STS) along withRaman and X-ray photoelectron spectroscopy to probe interfacialatomic structure and chemistry. STS reveals significant differences inelectronic interactions between graphene and Ge(110)/Ge(111),which is consistent with a model of stronger interaction on Ge(110) leading to epitaxial growth. Raman spectra indicate that thegraphene is considerably strained after growth, with more point-to-point variation on Ge(111). Furthermore, this native straininfluences the atomic structure of the interface by inducing metastable and previously unobserved Ge surface reconstructionsfollowing annealing. These nonequilibrium reconstructions cover 90 of the surface and, in turn, modify both the electronicand mechanical properties of the graphene overlayer. Finally, graphene on Ge(001) represents the extreme strain case, wheregraphene drives the reorganization of the Ge surface into [107] facets. From this work, it is clear that the interaction betweengraphene and the underlying Ge is not only dependent on the substrate crystallographic orientation, but is also tunable andstrongly related to the atomic reconfiguration of the grapheneGe interface.


Distribution Statement : APPROVED FOR PUBLIC RELEASE