Mapping the Dirac point in gated bilayer graphene

Deshpande, A.; Bao, W.; Zhao, Z.; Lau, C. N.; LeRoy, B. J.
December 2009
Applied Physics Letters;12/14/2009, Vol. 95 Issue 24, p243502
Academic Journal
We have performed low temperature scanning tunneling spectroscopy measurements on exfoliated bilayer graphene on SiO2. By varying the back gate voltage we observed a linear shift of the Dirac point and an opening of a bandgap due to the perpendicular electric field. In addition to observing a shift in the Dirac point, we also measured its spatial dependence using spatially resolved scanning tunneling spectroscopy. The spatial variation of the Dirac point was not correlated with topographic features and therefore we attribute its shift to random charged impurities.


Related Articles

  • Measurement of the quantum capacitance of graphene. Xia, Jilin; Chen, Fang; Li, Jinghong; Tao, Nongjian // Nature Nanotechnology;Aug2009, Vol. 4 Issue 8, p505 

    Graphene has received widespread attention due to its unique electronic properties. Much of the research conducted so far has focused on electron mobility, which is determined by scattering from charged impurities and other inhomogeneities. However, another important quantity, the quantum...

  • Evolution of microscopic localization in graphene in a magnetic field from scattering resonances to quantum dots. Suyong Jung; Rutter, Gregory M.; Klimov, Nikolai N.; Newell, David B.; Calizo, Irene; Hight-Walker, Angela R.; Zhitenev, Nikolai B.; Stroscio, Joseph A. // Nature Physics;Mar2011, Vol. 7 Issue 3, p245 

    Graphene exhibits rich new physics and great promise for applications in electronics. The half-integer quantum Hall effect and high carrier mobility are critically dependent on interactions with impurities/substrates and localization of Dirac fermions in realistic devices. We microscopically...

  • Single-layer behavior and slow carrier density dynamic of twisted graphene bilayer. Meng, Lan; Zhang, Yanfeng; Yan, Wei; Feng, Lei; He, Lin; Dou, Rui-Fen; Nie, Jia-Cai // Applied Physics Letters;2/27/2012, Vol. 100 Issue 9, p091601 

    We report scanning tunneling microscopy and scanning tunneling spectroscopy (STS) of twisted graphene bilayer on SiC substrate. For twist angle ∼4.5°, the Dirac point ED is located about 0.40 eV below the Fermi level EF due to the electron doping at the graphene/SiC interface. We...

  • Microwave switching of graphene field effect transistor at and far from the Dirac point. Deligeorgis, G.; Dragoman, M.; Neculoiu, D.; Dragoman, D.; Konstantinidis, G.; Cismaru, A.; Plana, R. // Applied Physics Letters;3/8/2010, Vol. 96 Issue 10, p103105 

    The dc and microwave experiments on a top-gate field effect transistor based on graphene, at and far from the Dirac point, are reported. Far from the Dirac point the transistor behaves as an active device, while at the Dirac point the transistor becomes a passive device, its amplification being...

  • Dirac voltage tunability by Hf1-xLaxO gate dielectric composition modulation for graphene field effect devices. Gun Oh, Joong; Shin, Yunsang; Cheol Shin, Woo; Sul, Onejae; Jin Cho, Byung // Applied Physics Letters;11/7/2011, Vol. 99 Issue 19, p193503 

    We report that the Dirac voltage of graphene field effect transistors (FETs) can be tuned by controlling the composition of hafnium lanthanum oxide (HfLaO) gate dielectrics. As the lanthanum percentage is increased in the HfLaO film, the charge neutrality point of the graphene FET is gradually...

  • Mystery of the insoluble films solved.  // TCE: The Chemical Engineer;Feb2015, Issue 884, p20 

    The article discusses the critical role of the metal impurities in the water dissolving property of graphene oxide membranes according to a study conducted by scientists from the Northwestern University in the U.S.

  • Negative Quantum Capacitance Induced by Midgap States in Single-layer Graphene. Lin Wang; Yang Wang; Xiaolong Chen; Wei Zhu; Chao Zhu; Zefei Wu; Yu Han; Mingwei Zhang; Wei Li; Yuheng He; Wei Xiong; Kam Tuen Law; Dangsheng Su; Ning Wang // Scientific Reports;6/21/2013, p1 

    We demonstrate that single-layer graphene (SLG) decorated with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance. The Ag adatoms act as resonant impurities and form nearly dispersionless resonant impurity bands near the charge neutrality point...

  • The exchange interaction effect in the scanning tunneling spectroscopy of a two-orbital Anderson impurity on metallic surface. Ding, G.; Ye, F.; Dong, B. // European Physical Journal B -- Condensed Matter;Jun2011, Vol. 81 Issue 4, p467 

    We investigate the scanning tunneling spectroscopy (STS) of a two-orbital Anderson impurity adsorbed on a metallic surface by using the numerical renormalization group (NRG) method. The density of state of magnetic impurity and the local conduction electron are calculated. We obtain the Fano...

  • Spin-orbit coupling, edge states and quantum spin Hall criticality due to Dirac fermion confinement: the case study of graphene. Tkachova, G.; Hentschel, M. // European Physical Journal B -- Condensed Matter;Jun2009, Vol. 69 Issue 4, p499 

    We propose a generalized Dirac fermion description for the electronic state of graphene terminated by a zigzag edge. This description admits a specific spin-orbit coupling needed to preserve time-reversal invariance of the zigzag confinement, otherwise, for spinless particles, showing the parity...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics