Growth of Carbon Structures on Stepped (211)Co Surfaces

Abstract

Density functional theory is used to evaluate the adsorption of carbon on stepped (211) cobalt surfaces. It is found that the 4-fold step hollow sites on (100) planes are the most stable adsorption sites for carbon, followed by the 3-fold hcp sites located in (111) terraces where adsorption per carbon atom is 0.7-0.9 eV less stable than that on the step sites. When the carbon concentration over the surface increases, adsorption of carbon chains is also favorable, and at even higher carbon pressures, interaction of adsorbed chains may lead to the formation of graphene sheets parallel to the (100) plane or to the formation of horizontally aligned seminanotubes. Formation of these carbon structures is accompanied by oxidation of the cobalt atoms, especially those forming the 4-fold step hollow site, whereas cobalt terrace sites become negatively charged. We discuss the significance of our results in relation to the catalyzed growth of single-walled carbon nanotubes on cobalt nanoparticles.

Effect of K on carbon adsorption and deposition on the Co(111) surface

“…Kong et al [34] showed that carbon easily diffuses to the step position of forming p4g surface carbide, and this transition is favored over the growth of small graphene islands. These results are also in agreement with those reported by Ramírez‐caballero et al [37] and Corral et al [4].…”

Atomistic modelling of CVD synthesis of carbon nanotubes and graphene

“…90,91 The interaction of individual C atoms or dimers has been widely studied on different TMs (Ni, Co, Fe, Pd) and noble metals (Cu, Ag, Au), possibly relevant for nanotube growth. [92][93][94][95][96][97][98] Different surface or subsurface sites have been considered, and C adsorption or incorporation in metal is generally less favourable than C incorporation in an innite graphene layer. The stability difference is of the order of 1 eV per C atom for the adsorption of a C atom on Ni, Pd and Pt, and in the 2-4 eV per C atom range for Cu, Ag and Au.…”

Two-dimensional heterostructures: fabrication, characterization, and application

“…Hundreds of transistors on a single chip 26 were made by MIT researchers in 2009, with very high frequency transistors produced on monolayer graphene on SiC. 27 Alternatively, a large variety of metals (Ni, [28][29][30][31][32][33][34][35][36][37][38] Cu, 37,[39][40][41][42][43][44] Pt, [45][46][47][48] Co, 37,49,50 Ru, 51,52 Ir, 53,54 Pd, 55 Ag, 56 Au, 57 Ga, [58][59][60] Ge, 61,62 Mo, 63,64 W, 64 Ti, 64 Zr, 64 Hf, 64 V, 64 Nb, 64 Ta, 64 and In 65 ) and alloys (Cu-Ni, 66,…”