Influence of ambient conditions on the electronic structure of graphene/copper interface

Abstract

Graphene films grown on the copper foils using chemical vapor deposition have been emphasized in the previous scientific studies and technical applications because of the high quality/cost ratio. However, no enough attention has been paid to the fundamentally important issue on the stability of graphene/copper interface compared with quality of the grown graphene films, though the properties of graphene/metal interface largely affect the Ohmic contacts in graphene-based electronics (e.g. highfrequency graphene transistors). Here, we investigated the electronic structure of graphene/copper interface which has been stored in the ambient conditions for different periods. Raman and photoelectron spectroscopic data indicated that the oxygen species do not prefer to adsorb on the graphene surface but insert into the graphene/copper interface. This results in the p-doping of graphene, formation of the surface positive dipole, and energy upshift of the graphene's Dirac point.

Patterning Large Free-Standing Reduced Graphene Oxide Films Assisted by Open-Area Copper Substrates for Graphene Drums

“…Qu et al verified the weak interaction between single-layer graphene films and copper substrates, and suggested that the main role of the Cu substrate in the graphene growth could be considered as a simple surface catalyst. 9 This procedure has been applied on metal surfaces, with different forms, by some groups, but the produced rGO film has always been analyzed over the substrate surface or after wet-etching procedures to remove the metal. 7−9 Open-area copper surfaces have been shown to be able to assist the growth of rGO films on its interstitial openings.…”

“…It can be used in several forms, usually as microflake powders or as thin films. The development of methodologies for its production is currently the focus of a plethora of publications. − …”

“…The strength of the interaction between graphene and the metal surface is a relevant parameter to consider. Qu et al verified the weak interaction between single-layer graphene films and copper substrates, and suggested that the main role of the Cu substrate in the graphene growth could be considered as a simple surface catalyst . This procedure has been applied on metal surfaces, with different forms, by some groups, but the produced rGO film has always been analyzed over the substrate surface or after wet-etching procedures to remove the metal. − …”

Adsorption of 1,3,5-Triphenylbenzene Molecules and Growth of Graphene Nanoflakes on Cu(100) Surface*

“…Peak 𝑔 is considered to be spectroscopic evidence for the hybridization of the C 𝜋 network with Cu 𝑑-orbitals; [55] peak ℎ is the GNFs C 2𝑝 𝜋 bands; peak 𝑖 is defined as the mixture of the GNFs C 2𝑝 𝜋 and 2𝑝 𝜎 bands; peak 𝑗 is the GNFs C 2𝑝 𝜎 bands; and peak 𝑘 is associated with the GNFs C 2𝑠 and 2𝑝 hybridized states. [56,57] The nominal coverages of the TPB film of each spectrum are 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0 ML near the secondary electron cutoff energy in Fig. 1(b…”