Selective molecular transport through intrinsic defects in a single layer of CVD graphene.

We report graphene composite membranes with nominal areas more than 25 mm(2) fabricated by transfer of a single layer of CVD graphene onto a porous polycarbonate substrate. A combination of pressure-driven and diffusive transport measurements provides evidence of size-selective transport of molecules through the membrane, which is attributed to the low-frequency occurrence of intrinsic 1-15 nm diameter pores in the CVD graphene. Our results present the first step toward the realization of practical membranes that use graphene as the selective material.

Topographic and spectroscopic characterization of electronic edge states in CVD grown graphene nanoribbons.

We used scanning tunneling microscopy and spectroscopy (STM/S) techniques to analyze the relationships between the edge shapes and the electronic structures in as-grown chemical vapor deposition (CVD) graphene nanoribbons (GNRs). A rich variety of single-layered graphene nanoribbons exhibiting a width of several to 100 nm and up to 1 μm long were studied. High-resolution STM images highlight highly crystalline nanoribbon structures with well-defined and clean edges.

Role of kinetic factors in chemical vapor deposition synthesis of uniform large area graphene using copper catalyst.

In this article, the role of kinetics, in particular, the pressure of the reaction chamber in the chemical vapor deposition (CVD) synthesis of graphene using low carbon solid solubility catalysts (Cu), on both the large area thickness uniformity and the defect density are presented. Although the thermodynamics of the synthesis system remains the same, based on whether the process is performed at atmospheric pressure (AP), low pressure (LP) (0.1-1 Torr) or under ultrahigh vacuum (UHV) conditions, the kinetics of the growth phenomenon are different, leading to a variation in the uniformity of the resulting graphene growth over large areas (wafer scale).

Synthesis, characterization, and optical properties of ordered arrays of III-nitride nanocrystals.

A new approach involving self-assembling block copolymer micellar templates and gas-phase reactions to synthesize arrays of monodisperse III-nitrides nanocrystals in the size range of 1-5 nm with uniform spacings between the nanoparticles is demonstrated. The photoluminescence emission spectra revealed the GaN nanocrystals are in the quantum-confined regime. This method not only offers great promise for the controlled synthesis of arrays of ternary III-nitride nanocrystals but may also enable doping in binary nitrides.