Qinghong Yuan

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Ground-state structures of supported C clusters, C(N) (N = 16, ..., 26), on four selected transition metal surfaces [Rh(111), Ru(0001), Ni(111), and Cu(111)] are systematically explored by ab initio calculations. It is found that the core-shell structured C(21), which is a fraction of C(60) possessing three isolated pentagons and C(3v) symmetry, is a very(More)
Hexagonal boron nitride (h-BN) has attracted significant attention because of its superior properties as well as its potential as an ideal dielectric layer for graphene-based devices. The h-BN films obtained via chemical vapour deposition in earlier reports are always polycrystalline with small grains because of high nucleation density on substrates. Here(More)
The energetics of topological defects (TDs) in carbon nanotubes (CNTs) and their kinetic healing during the catalytic growth are explored theoretically. Our study indicates that, with the assistance of a metal catalyst, TDs formed during the addition of C atoms can be efficiently healed at the CNT-catalyst interface. Theoretically, a TD-free CNT wall with(More)
Defects play significant roles in properties of graphene and related device performances. Most studies of defects in graphene focus on their influences on electronic or luminescent optical properties, while controlling infrared optoelectronic performance of graphene by defect engineering remains a challenge. In the meantime, pristine graphene has very low(More)
Open, sesame! Graphene nanoribbons (GNRs) with smooth edges and controllable widths are crucial for graphene electronic and spintronic applications. High-quality narrow GNRs can be synthesized from single-walled carbon nanotubes at 200-300 °C using a Cu-atom catalyst, which dramatically reduces the energy barrier of unzipping from 3.11 to 1.16 eV.
Wafer-scale single-crystalline graphene monolayers are highly sought after as an ideal platform for electronic and other applications. At present, state-of-the-art growth methods based on chemical vapour deposition allow the synthesis of one-centimetre-sized single-crystalline graphene domains in ∼12 h, by suppressing nucleation events on the growth(More)
Three key positions of graphene on a catalyst surface can be identified based on precise computations, namely as sunk (S), step-attached (SA), and on-terrace (OT). Surprisingly, the preferred modes are not all alike but vary from metal to metal, depending on the energies of graphene-edge "wetting" by the catalyst: on a catalyst surface of soft metal like(More)
Owing to the unique structure of zigzag (ZZ) carbon nanotubes (CNTs), their ring-by-ring growth behavior is different from that of chiral or armchair (AC) CNTs, on the rims of which kinks serve as active sites for carbon attachment. Through first-principle calculations, we found that, because of the high energy barrier of initiating a new carbon ring at the(More)
The unidirectional alignment of graphene islands is essential to the synthesis of wafer-scale single-crystal graphene on Ge(110) surface, but the underlying mechanism is not well-understood. Here we report that the necessary coalignment of the nucleating graphene islands on Ge(110) surface is caused by the presence of step-pattern; we show that on the(More)