Doping of graphene by a Au(111) substrate: Calculation strategy within the local density approximation and a semiempirical van der Waals approach

Abstract

We have performed a density functional study of graphene adsorbed on Au(111) surface using both a local density approximation and a semiempirical van der Waals approach proposed by Grimme, known as the DFT-D2 method. Graphene physisorbed on metal has the linear dispersion preserved in the band-structure, but the Fermi level of the system is shifted with respect to the conical points which results in a doping effect. We show that the type and amount of doping depends not only on the choice of the exchange-correlation functional used in the calculations, but also on the supercell geometry that models the physical system. We analyzed how the factors such as the in-plane cell parameter and interlayer spacing in gold influence the Fermi level shift and we found that even a small variation in these parameters may cause a transition from p-type to n-type doping. We have selected a reasonable set of model parameters and obtained that graphene is either undoped or at most slightly p-type doped on the clean Au(111) surface, which seems to be in line with experimental findings. On the other hand, modifications of the substrate lattice may induce larger doping up to 0.30-0.40 eV depending on the graphene-metal adsorption distance. The sensitivity of the graphene-gold interface to the structural parameters may allow to tune doping across the samples which could lead to possible applications in graphene-based electronic devices. We believe that the present remarks can be also useful for other studies based on the periodic DFT.

Electronic and Magnetic Properties of Zigzag Graphene Nanoribbons on the (111) Surface of Cu, Ag, and Au

“…This behavior is in contrast to the case of Au(111), where doping is essentially negligible. The doping of perfect monolayer graphene has also been shown to depend sensitively on the type of metal substrate, even in the weak bonding case [37][38][39][40] (see also the discussion in the Supplement).…”

Doping domains in graphene on gold substrates: First-principles and scanning tunneling spectroscopy studies

“…In our recent work, we have analyzed the correlation between the adsorption geometry and electronic properties of the graphene/Au(111) interface and we have shown the influence of the geometry parameters characterizing the modeled system 17 . We focused mainly on the aspects related to the strategy of the calculations, i.e.…”

“…It results in doping by the holes (electrons) transferred from a metal to graphene which becomes p-type (n-type) doped. According to most of the theoretical studies [12][13][14][15][16][17][18][19] , graphene on Al, Ag and Cu is n-type doped, while interaction with Au and Pt(111) surfaces seems to cause p-type doping. Although the particular DFT calculations can lead to different values of the doping level for the same metal, it is usually assumed that one type of substrate implies definite type and level of doping and any contradictions are related to the limitations of ab initio methods whose results depend on the choice of the exchange-correlation interaction and on the calculation strategy 17 …”

“…Furthermore, the adsorption distance which has the strongest influence on doping level (see Fig.3 in Ref. 17) can be, in practice, set arbitrarily, since the equilibrium position of the graphene sheet with respect to Au depends directly on the choice of one from many possible exchange-correlation functionals.…”

Probing Electronic Properties of Graphene on the Atomic Scale by Scanning Tunneling Microscopy and Spectroscopy

“…Fourth, dI/dV measurements indicate that the Dirac point of graphene on the Au(111) surface is located at ∼ E F [38], which indicates that no appreciable doping of graphene exists for graphene/Au. DFT calculations show small shifts of the Dirac point for graphene on Au [88,92,[115][116][117]. ARPES measurements show that an intercalated Au layer can electronically decouple graphene from the substrate for graphene on Ru(0001) [118], graphene on Ni(111) [119,120], and graphene on SiC [121].…”