Abstract: Graphene, the thinnest two-dimensional material in nature, has abundant distinctive properties, such as ultrahigh carrier mobility, superior thermal conductivity, and anomalous quantum Hall effect. In this talk, I will present a few recent work made in our group on growth mechanism and property exploration in graphene.
Synthesizing graphene nanoribbons (GNRs) with smooth edges and controllable widths is a prerequisite for many graphene applications. We proposed two efficient methods of making narrow GNRs: using a single transition metal atom to unzip single-walled carbon nanotubes (SWNTs) in H2 gas; and applying a uniaxial external strain to cut graphene sheet into GNRs on oxidation. The mechanism of directivity of transition metal nanoparticles catalytic cutting of graphene is theoretically well explained with ab initio method. We further explored the CVD growth mechanism and the defect healing mechanism and their kinetic dynamics behaviors.
On the property aspects, we designed a new class of quasi-one-dimensional graphene nanostructures, namely, the tri-wing graphene (TWG) nanoribbons, which it not only possesses significantly mechanical stability, but also own rich electronic and magnetic properties. We further revealed that the approaching hydrogen atoms from both sides of a few layer graphene induce a structural transition from a layered structure into a hydrogen passivated thin diamond film. The sealing of graphene as that in silicon microelectronic industry showed that single atomic thick graphene and GNR sealed between diamond layers maintain their intrinsic electronic properties. The imperfection (defects) can enhance the interaction between metal atom and graphene substrate and achieve tunable magnetic properties.

Date&Time: November 20, 2013 (Wednesday), 10:30-11:30 a.m.
Location: 606 Conference Room, No.3 Heqing Road, Haidian District