AI Article Synopsis
- The study examines pristine and hydrogen-intercalated graphene on a 4H-SiC(0001) substrate using a specialized imaging technique called noncontact scanning nonlinear dielectric potentiometry (NC-SNDP).
- It finds that the pristine graphene-SiC interface has permanent dipole moments due to covalent bonds from the buffer layer, which are disrupted by hydrogen intercalation.
- While hydrogen intercalation converts the buffer layer into a second graphene layer, some silicon dangling bonds remain, potentially reducing carrier mobility in the hydrogen-intercalated graphene.
Article Abstract
We investigate pristine and hydrogen-intercalated graphene synthesized on a 4H-SiC(0001) substrate by using noncontact scanning nonlinear dielectric potentiometry (NC-SNDP). Permanent dipole moments are detected at the pristine graphene-SiC interface. These originate from the covalent bonds of carbon atoms of the so-called buffer layer to the substrate. Hydrogen intercalation at the interface eliminates these covalent bonds and the original quasi-(6×6) corrugation, which indicates the conversion of the buffer layer into a second graphene layer by the termination of Si bonds at the interface. NC-SNDP images suggest that a certain portion of the Si dangling bonds remains even after hydrogen intercalation. These bonds are thought to act as charged impurities reducing the carrier mobility in hydrogen-intercalated graphene on SiC.
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| http://dx.doi.org/10.1103/PhysRevLett.114.226103 | DOI Listing |
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