Tuning the Fermi Level of SiO₂-Supported Single-Layer Graphene by Thermal Annealing

Abstract

The effects of thermal annealing in inert Ar gas atmosphere of SiO2-supported, exfoliated single-layer graphene are investigated in this work. A systematic, reproducible change in the electronic properties of graphene is observed after annealing. The most prominent Raman features in graphene, the G and 2D peaks, change in accord to what is expected in the case of hole doping. The results of electrical characterization performed on annealed, back-gated field-effect graphene devices show that the neutrality point voltage V NP increases monotonically with the annealing temperature, confirming the occurrence of excess hole accumulation. No degradation of the structural properties of graphene is observed after annealing at temperatures as high as 400 °C. Thermal annealing of single-layer graphene in controlled Ar atmosphere can therefore be considered a technique to reproducibly modify the electronic structure of graphene by tuning its Fermi level.

Layer Dependent Wetting in Parahexaphenyl Thin Film Growth on Graphene

“…Electron doping increased the oxygen diffusion coefficient on Gr by nine orders of magnitude. This is a quite interesting fact, especially when considering that heating procedures can lead to Gr doping on SiO 2 [66,67] which may significantly alter the diffusion properties depending on the sample history.…”

Ultraclean freestanding graphene by platinum-metal catalysis

“…1(v)], i.e., well below the oxidation temperature of graphene in air. 14,23 III. RESULTS AND DISCUSSION Figure 2 illustrates the degradation of the PMMA capping due to the presence of the catalytic metal while it remains present on a noble metal, i.e., gold in this case.…”

“…4,9,10 The removal of the approximately 100 nm thick PMMA layer is a challenge and extensive efforts have been undertaken in the past few years to establish a reliable technique to retrieve the pristine graphene without PMMA residues. [3][4][5][11][12][13][14] Well-known chemical etchants for PMMA are acetone and chloroform. 15 Unfortunately, wet chemical treatment of the polymer leads to contaminated graphene layers with lots of residues left behind.…”

“…15 Unfortunately, wet chemical treatment of the polymer leads to contaminated graphene layers with lots of residues left behind. Thermal annealing at temperature in the range of 300-400 C in vacuum 14,15 or in an Ar/H 2 atmosphere 15 appears to help the cleaning process. However, besides the fact that these techniques are not easily available, they do not lead to ultraclean freestanding graphene free from hydrocarbon contaminations [16][17][18] or polymer residues.…”

Development and characterization of graphene-based electronic devices

“…As a result, sometimes burst regions arise that modify the device electrical properties. As the local temperature reaches values above a certain temperature (typically close to 300 • C), graphene interaction with the substrate is increased, leading to substrate-induced doping [84,140,141]. For the case depicted in Fig.…”