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Electrical properties of graphene adatoms

Electrical properties of graphene adatoms. Xing Liu. Motivation. Why attach adatoms onto graphene Open band gap Hydrogen storage Study charged-impurity scattering Graphene device … … Our goal : study the effect of light on their electrical properties

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Electrical properties of graphene adatoms

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  1. Electrical properties of grapheneadatoms Xing Liu

  2. Motivation • Why attach adatoms onto graphene • Open band gap • Hydrogen storage • Study charged-impurity scattering • Graphenedevice • … … • Our goal: study the effect of light on their electrical properties • 780nm laser will be used which near the D2 transition of Rb • Tuning the laser as precise knob to control the electrical properties of the adatoms

  3. Theoretical approach

  4. Rb-graphene: structural and energy properties From first-principles DFT the angle formed by the C–C–C bonds is 115.02o while the Li–C–C angle is 76.92o

  5. Electronic properties: • We expect similar behavior for Rb-graphene and Li-grapheneand will use this to confirm our doping.

  6. Raman spectroscopy: Graphene device Doped graphene device • G peak and 2D peak intensity decrease • No D and D’ peak.

  7. Our goal • Study the effect of light on their electrical properties • A 780 nm laser which turned near the D2 transition of Rubidium is expected to change its electronic density distribution. • Modified electrical properties is resulted from the change in charge density around the C-atoms. • The laser would serve as a precise knob to control the electrical properties of adatoms.

  8. Theoretical backgroud: • From first-principle DFT calculation, for group I adatoms, the density of states provided evidence for ionic bonding and charges transfer between the adsorbate and substrate. D2 transition :5s1/2 5p3/2 A laser will be used to trigger electron jump form 5s1/2to5s1/2 , which may enhance ionic bonding, hence induce more charge transfer. From wiki

  9. Theoretical backgroud(cont'd) Charged impurity scattering

  10. Experiment setup • A six-way flange cross will be used as a vacuum chamber.

  11. Reference: • KT Chan, JB Neaton, ML Cohen - Physical Review B, 2008 – APS • Shytov, Andrei V., Dmitry A. Abanin, and Leonid S. Levitov. “Long-Range Interaction between Adatoms in Graphene.” Physical Review Letters 103.1 (2009): 016806.(C) 2010 TheAmericanPhysical Society. • Phys. Rev. B 47, 13713–13721 (1993) • Paulo V C Medeiros et al 2010 Nanotechnology 21 115701 • Phys. Rev. B 69, 155422 (2004) • Appl. Phys. Lett. 96, 123112 (2010); doi:10.1063/1.3368704  • Phys. Rev. Lett. 98, 186806 (2007)  • Phys. Rev. B 77, 195434 (2008) • Nature Physics 4, 377 - 381 (2008)  • Appl. Phys. Lett. 94, 163115 (2009); doi:10.1063/1.3126008

  12. The end… Thank you!

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