Evidence of the role of contacts on the observed electron-hole asymmetry in graphene
By N. Stander, B. Huard, J. Sulpizio, David Goldhaber-Gordon. 2008
361 citations recorded by the source corpus.
We perform electrical transport measurements in graphene with several sample geometries. In particular, we design ``invasive'' probes crossing the whole graphene sheet as well as ``external'' probes connected through graphene side arms. The four-probe conductance measured between external probes varies linearly with charge density and is symmetric between electron and hole types of carriers. In contrast measurements with invasive probes give a strong electron-hole asymmetry and a sublinear conductance as a function of density. By comparing various geometries and types of contact metal, we show that these two observations are due to transport properties of the metal/graphene interface. The asymmetry originates from the pinning of the charge density below the metal, which thereby forms a $p\text{\ensuremath{-}}n$ or $p\text{\ensuremath{-}}p$ junction, depending on the polarity of the carriers in the bulk graphene sheet. Our results also explain part of the sublinearity observed in conductance as a function of density in a large number of experiments on graphene, which has generally been attributed to short-range scattering only.
Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/a735998cce8ff6d650f5cee150437e67374ab827
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Citations in the corpus
- Resistivity of Graphene Nanoribbon Interconnects (2009, background): “The data from [2] and [12] are extracted at 200 and 4 K, respectively.”
- Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene. (2013, background): “al potential at the graphene/metal interface and the longranged - electrostatic effect of the nearby metal on graphene due to their different workfunctions[28], and (2) asymmetry in contact resistance[29]. The first effect is inevitable in our dissimilarmetal contacted - devices. Additional scatteri”
- Electronic transport in two-dimensional graphene (2010, background): “Although, it is not clear what role contact resistance (Blake et al., 2009; Blanter and Martin, 2007; Cayssol et al., 2009; Giovannetti et al., 2008; Golizadeh-Mojarad and Datta, 2009; Huard et al., 2008; Lee et al., 2008b) played in these 2-probe measurements.”
- Transport in inhomogeneous quantum critical fluids and in the Dirac fluid in graphene (2015, background): “However, some regions of the sample (notably close to the contacts on the edges [69], or regions very close to impurities) may have such large local values of μ0 that they are always in a Fermi liquid regime.”
- Electronic properties of mesoscopic graphene structures: Charge confinement and control of spin and charge transport (2011, neutral): “[181].”
- The origins and limits of metal-graphene junction resistance. (2011, methodology): “The graphene under the metal is doped by charge transfe”
- Colloquium: The transport properties of graphene: An introduction (2010, background): “Another source of electron-hole asymmetry of the conductivity is originated in the metal contacts of the transistor (Huard et al., 2008).”
- Water on graphene: review of recent progress (2018, background): “tions Experimentally, it was shown that the intrinsic doping level and mobility of field effect devices vary widely and their characteristics exhibit hysteretic behaviour under ambient conditions[68]–[70]. Studies concerned with the effect of ambient air exposure on the electronic properties of grap”