Chemical Vapor Deposition of N-Doped Graphene and Carbon Films: The Role of Precursors and Gas Phase

Abstract

Thermally induced chemical vapor deposition (CVD) was used to study the formation of nitrogen doped graphene and carbon films on copper from aliphatic nitrogen containingprecursors consisting of C 1 -and C 2 -units and (hetero) The deposition of carbon films from the gas phase leads to materials of widely different structure and composition. The films can be i) crystalline, e.g. like graphene, graphite or diamond and consist ideally of a single type of either sp 2 or sp 3 -hybridized carbon atoms, ii) can contain domains of any of these phases in more or less ordered arrangements, or iii) can even incorporate a considerable amount of hydrogen or other heteroatoms. Within this manifold of carbon films, graphene, a two-dimensional allotrope of carbon has recently attained high interest due to its electronic and optical properties and chemical inertness. [1][2][3] Graphene with controllable electronic properties is expected to be a promising material for the development of new electronic devices, 4,5 such as e.g. field-effect transistors 6 or electrochemical sensors, 7,8 as well as for applications in energy storage 9,10 and conversion systems like super capacitors, 11 lithium batteries, 12 and fuel cells. 13 Furthermore, transparent conducting graphene films are considered for organic electronic devices such as OLED's and organic solar cells. 14 Graphene itself does not reveal a band gap and therefore has no intrinsic semiconducting properties. Thus, doping of graphene with heteroelements like boron (B) or nitrogen (N), which fit into the carbon lattice, is an important issue. Theoretical and experimental studies indicate that B-or N-doped graphenes reveal p-or n-type semiconductor characteristics [15][16][17] accompanied by a band gap opening [18][19][20] and thus doped 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 graphene and structurally related graphene nanoribbons are considered as promising materials with tunable electronic properties. 21,22 N-Doped graphene, and particularly B-doped graphene are still scarcely investigated experimentally as compared to graphene 23 and graphene oxide. 24 So far, few methods for generating N-doped graphene are described. Among these are thermal CVD of methane and ammonia gas, 25 CVD of molecular precursors like pyridine 26 or acetonitrile 27 on a Cu substrate or exposure of graphene to a nitrogen 28 or ammonia 29 containing plasma discharge.In these reactions, the presence of nitrogen was identified by XPS, whereas the mechanism for nitrogen incorporation at specific positions of the graphene lattice is still not understood. 15,16,30 Recently, the formation mechanism of graphene from molecular precursors has been investigated. From the decay it was reasoned that dicarbon (C 2 -) species, formed as reaction intermediates, can contribute significantly to the built-up of graphene. 31 Sin...

Superaerophobic graphene nano-hills for direct hydrazine fuel cells

“…Apart from the difference in morphology between FG and VGNH-45, their chemical nature remains the same, as evidenced from the X-ray photoelectron spectroscopy spectra of C 1s shown in Supplementary Figure S6. 26,27 The tail between 286 and 290 eV refers to C − O, C = O, and energyloss 'shake-up' features. 22 Furthermore, the X-ray photoelectron Figure S7) shows a strong C 1s peak at 285 eV, a Si 2p3 peak at 102 eV due to the SiO 2 /Si substrate, a small O 1s peak at 533 eV and a weak O KLL Auger band between 970 and 980 eV.…”

Graphene based metal and metal oxide nanocomposites: synthesis, properties and their applications

“…29 The bottom-up growth of graphene sheets is an alternative to the mechanical exfoliation of the bulk graphite. In bottom-up processes, graphene is synthesized by a variety of methods such as chemical vapor deposition (CVD), 45,46 arc discharge, 47 epitaxial growth on SiC, 48 chemical conversion, 49 reduction of CO, 50 unzipping carbon nanotubes 51,52 and self-assembly of surfactants. 53 The CVD approach to produce graphene relies on dissolving carbon into metal surfaces, such as Ni and Cu that act as catalysts 54,55 and then forcing it to separate by cooling the metal.…”

Efficient exfoliation N-doped graphene from N-containing bamboo-like carbon nanotubes for anode materials of Li-ion battery and Na-ion battery

“…5b). They were assigned to N atom substituted in five-membered C ring (pyrrolic-N) and N atom embedded in graphite sheets (graphitic-N), labeled as N1 and N2 [32,36,37]. Graphitic-N is the main composition of N-C specifics and accounts for 68.7 %.…”

“…5c). Besides sub-peaks of pyrrolic-N and graphitic-N, a sub-peak corresponding to pyridinic-N, which was N-substituted in a six-membered C ring (pyridinic-N) [32,36,37], and the sub-peaks corresponding to N and O bonding [38] were resolved from BCNT N1s peak, which were labeled as N0 and N3-N5, respectively.…”