Ultrathin Epitaxial Graphite:  2D Electron Gas Properties and a Route toward Graphene-based Nanoelectronics

Abstract

We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically 3 graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H-SiC, and characterized by surface-science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kΩ to 225 kΩ at 4 K, with positive magnetoconductance). Low resistance samples show characteristics of weak-localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 10 12 cm −2 per graphene sheet. The most highlyordered sample exhibits Shubnikov -de Haas oscillations which correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic techniques, and we demonstrate modulation of the film conductance using a top-gate electrode. These key elements suggest electronic device applications based on nano-patterned epitaxial graphene (NPEG), with the potential for large-scale integration.

The extended growth of graphene oxide flakes using ethanol CVD

“…From graphene it is known that it provides 2D electron gas properties, comparable with metal 60 surfaces. 19 From existing literature it is known that carbon cannot crystallize well by deposition from carburizing gases at low temperature without catalytic activation because of its strong C−C bonds and high melting temperature. To form good 65 crystalline carbon, the carbon atoms must dissolve, diffuse through metal particles, and crystallize on an appropriate facet that can act as a template to help the epitaxial growth of carbon crystals.…”

Raman Scattering from High-Frequency Phonons in Supported n-Graphene Layer Films

“…In one case, this was elegantly accomplished by mounting a small graphite crystal on a tip-less cantilever held in an atomic force microscope (AFM) 10 . Thin n~3 nGLs have also been fabricated by the preferential thermal evaporation of Si from the (0001) surface of SiC in ultrahigh vacuum and they have been shown to also exhibit oscillatory magnetoresistance 14 .…”

Transport Gap Opening and High On–Off Current Ratio in Trilayer Graphene with Self-Aligned Nanodomain Boundaries

“…1 Although mechanical exfoliation of graphene from graphite is an effective and successful sample preparation method for fundamental research, it is found that roughly 60% of trilayer samples prepared this way have a pure ABA stacking order, while the remainder exhibit mixed ABA-ABC stacking orders. Alternatively, chemical vapor deposition, 27,28 and vacuum synthesis on silicon carbide surfaces [29][30][31][32] are excellent ways to fabricate large-area few-layer and monolayer graphene. It is known that the graphene produced by these techniques typically contains domainboundaries, [30][31][32][33][34][35] which can considerably modify the electronic transport in the graphene.…”