Mapping of nanomechanical and electronic properties of quasi-free standing graphene
Graphene grown on SiC(0001) exhibits intrinsic electron doping due to charge transfer from the interfacial layer (IFL). IFL is a (6√(3 ) × 6√(3 ))R30 º reconstructed layer, topographically similar to graphene, but with a significant amount of carbon atoms still covalently bonded to the SiC(0001) surface, altering the graphene electronic properties and reducing the carrier. Hydrogen intercalation breaks the C-Si bonds and creates Si-H bonds, lifting the IFL and converting it to freestanding graphene monolayer.
Using a combination of Kelvin probe force microscopy (KPFM, surface potential) and ultrasonic force microscopy (UFM, stiffness) we investigate the electronic and nanomechanical properties of the as-grown and ex-situ intercalated graphene. Predominantly, monolayer graphene films were grown by CVD on the Si-face of 4H-SiC(0001), followed by ex-situ H2 intercalation. The samples were studied using AFM, KPFM, UFM and Raman spectroscopy.
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